Dissertations / Theses: 'Cu2ZnSnS4'

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Kühnlein, Holger H. "Elektrochemische Legierungsabscheidung zur Herstellung von Cu2ZnSnS4 Dünnschichtsolarzellen." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2007. http://nbn-resolving.de/urn:nbn:de:swb:14-1194790522501-93202.

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Die als Absorbermaterial für Dünnschichtsolarzellen geeigneten Verbindungshalbleiter Cu2ZnSnS4 (CZTS) und Cu2ZnSnS(4-x)Sex (x<3, CZTSSe) konnten erfolgreich durch Kombination der elektrochemischen Legierungsabscheidung und der anschließenden Sulfurisierung in H2S-haltiger Atmosphäre hergestellt werden. In früheren Arbeiten wurden die viel versprechenden Eigenschaften von CZTS und Cu2ZnSnSe4 (CZTSe), als In und Ga freie und damit kostengünstige Alternativen, bereits ausführlich vorgestellt. Im Rahmen dieser Arbeit konnte anhand von kristallographischen Ergebnissen sowie durch Untersuchungen der Bandlückenenergien bestätigt werden, dass die Kesterite CZTS (1,46eV) und CZTSSe (1,32eV) erfolgreich mittels einer nasschemischen Vorstufe herstellbar sind. Weiterhin wurde erstmalig der Zusammenhang unterschiedlicher Stöchiometrien anhand ermittelter Halbleitereigenschaften (Na, Eg, EFB) gezeigt. Auf diesen Ergebnissen basierend wurde eine optimale Zusammensetzung zur Herstellung funktionaler Absorberschichten bestimmt. Dennoch zeigt sich, dass die Prozessparameter der Gasphasen-Sulfurisierung entscheidend die Bildung homogener Schichten beeinflusst. Die beobachtete große Kristallverteilung und die dabei auftretenden lokalen Löcher setzten die Funktionalität der hergestellten Solar Zellen (Al/ZnO:Al/CdS/CZTS/Mo/Glas) deutlich herab. Trotz der geringen Wirkungsgrade konnte aus einer Reihe unterschiedlicher Absorbermaterialien eine optimale Stöchiometrie (~Cu2Zn1.1Sn0.9S4) ermittelt werden. Die elektrochemische Coabscheidung von Se (~Cu2Zn1.2Sn0.9Se0.3) und die dadurch erfolgte partielle Substitution von S durch Se bewirkte, verglichen zur CZTS Morphologie, eine kompaktere und geschlossene Schichtstruktur. Der Einfluss des Selenanteils wurde dabei anhand detaillierter kristallographischer Untersuchungen und einer reduzierten Bandlückenenergie (1,32eV) bestätigt. Obwohl deutlich reproduzierbare Diodeneigenschaften über große Flächen beobachtet wurden, konnten keine Verbesserung des Wirkungsgrads erzielt werden. Cu2ZnSn (CZT) und Cu2ZnSnSe0.3 (CZTSe) Precursorschichten wurden mittels eines neu entwickelten alkalischen sowie zyanidfreien Elektrolyten auf Mo beschichteten Glassubstraten abgeschieden. Dieser alkalische Elektrolyt zeigte eine hohe Langzeitstabilität und die bisher unbekannte Möglichkeit der Abscheidung hoher Zinnanteile bei niedrigen Temperaturen. Aufgrund detaillierter elektrochemischer Untersuchungen konnte ein fundamentales Verständnis hinsichtlich der Einflüsse unterschiedlicher Additive, Konzentrationen und Temperaturen erzielt werden. Diese Ergebnisse konnten zur Interpretation der beobachteten potentialabhängigen Legierungsbildung herangezogen werden. Im Rahmen eines wesentlich fundamentalen Ansatzes erfolgte weiterhin die Charakterisierung der Legierungsbildung, ausgehend von unterschiedlicher Metallgehalte im Elektrolyten, anhand eines kürzlich publizierten kinetischen Modells zur elektrochemischen Legierungsabscheidung. Basierend auf diesen Untersuchungen konnte das vorgestellte Badsystem aufgrund einer genauen Einstellbarkeit und Nachdosierung erfolgreich zur ternären Abscheidung von Precursorschichten verwendet werden
Cu2ZnSnS4 (CZTS) and Cu2ZnSnS(4-x)Sex (x<0.3, CZTSSe) thin film solar cell absorber materials were successfully formed by combining a one step electrochemical precursor deposition followed by a vapour phase sulfurization process. CZTS and Cu2ZnSnSe4 (CZTSe) are known as promising candidates for thin film solar cell applications without using rare and thus expensive materials like In and Ga. This thesis confirmed by XRD and band gap energy data the potential to produce the kesterite type semiconductor materials CZTS (1,46eV) and CZTSSe (1,32eV) via a wet chemical precursor step. This paper presents for the first time the impact of different absorber compositions on semiconductor properties (NA, Eg, EFB) of the bulk material. Based on this data an optimum stoichiometry was identified to produce a functional absorber layer. However, sulfurization remained as the most critical process to achieve homogeneous thin films. In the most cases local pin holes and a large crystal size distribution diminished the conversion efficiency of produced solar cell samples (Al/ZnO:Al/CdS/CZTS/Mo/glass). Nevertheless an optimum performance was found for a slight excess of Zn (~Cu2Zn1.1Sn0.9S4). The electrochemical codeposition of Se (~Cu2Zn1.2Sn0.9Se0.3) at the precursor step enabled to do a partial substitution of S by Se which was identified to improve CZTS morphology into a homogeneous and dense layer. The expected impact of Se was also confirmed by detailed crystallographic and band gap energy (1.32eV) measurements. Although solar cell function was found for enlarged areas the low overall conversion efficiency could be not pushed to higher levels. Cu2ZnSn (CZT) and Cu2ZnSnSe0.3 (CZTSe) precursor layers were directly electrodeposited on Mo coated soda line glass substrates from a new developed alkaline cyanide free alloy bath system. The presented electrolyte showed high long term stability and an up to now unknown high rate of Sn codeposition at low electrolyte temperatures. Results of a detailed electrolyte characterization gave a fundamental understanding of additive, concentration and temperature effects. This knowledge was successfully linked to explain the potential depended alloy composition effects. As a more fundamental approach a new kinetic model of the electrochemical alloy deposition was used to characterize the impact of changed electrolyte metal contents on the resulting alloy composition. Based on this data the presented alloy bath system was successfully applied for precise adjustment and replenishment during the ternary precursor deposition

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Handwerg, Martin. "Thermische und elektrische Eigenschaften der funktionellen Halbleiter beta-Ga2O3, Cu2ZnSnS4 und Cu2ZnSnSe4." Doctoral thesis, Humboldt-Universität zu Berlin, 2019. http://dx.doi.org/10.18452/20384.

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Halbleitermaterialien sind in den elektrischen Anwendungen der heutigen Zeit unerlässlich geworden. In dieser Arbeit wird der Fokus auf die Untersuchung der elektrischen und thermischen Eigenschaften von zwei Halbleiterklassen gelegt. Zum einen wird mit -Ga2O3 ein Mitglied der Klasse der transparenten leitfähigen Oxide untersucht.Hier wurden die elektrischen Eigenschaften von dünnen Schichten (Dicke von 28nm-225nm) und Volumenkristallen temperaturabhängig untersucht.Dabei zeigt sich bei Volumenkristallen und mindestens 150nm dicken Schichten eine Steigerung der elektrischen Leitfähigkeit bis 100K durch die Streuung von Elektronen an Störstellen und bei Temperaturen über 100K wieder ein Abfall der elektrischen Leitfähigkeit durch Elektron-Phonon-Wechselwirkung. Die Untersuchung der thermische Leitfähigkeit von beta-Ga2O3 zeigt ein anisotropes Verhalten mit minimalen Werten in [100]-Richtung und maximalen Werten in [010]-Richtung. Die Temperaturabhängigkeit der thermischen Eigenschaften zeigt eine Verringerung der thermischen Leitfähigkeit und der thermischen Diffusivität mit steigender Temperatur. Eine zweite untersuchte Materialklasse ist die der Kesterite. Zu dieser Kristallstruktur wurden zwei Elementkonfigurationen untersucht, Kupfer-Zink-Zinn-Sulfid und Kupfer- Zink-Zinn-Selenid. Der Transport bei Raumtemperatur und darunter findet über verschiedene Tunnelprozesse lokalisierter Ladungsträger statt. Zusätzlich wird auf die Veränderung der elektrischen Eigenschaften durch die Kristallinität und Komposition eingegangen. Die thermischen Eigenschaften zeigen analog zum beta-Ga2O3 eine Dominanz der Phonon-Phonon-Umklapp-Streuung bei hohen Temperaturen, während bei niedrigen Temperaturen Streuung an Störstellen und Grenzflächen vorherrscht. Methodisch zeigt diese Arbeit unterschiedlichste Messmethoden zur Charakterisierung der elektrischen und thermischen Eigenschaften, welche die Standardmethoden sowohl nutzen, als auch sinnvoll erweitern.
Semiconductors are essential for electronic applications nowadays. Here, the electrical and thermal properties of two semiconductor classes with huge application potential are investigated. As a transparent conducting oxide beta-Ga2O3 is investigated. In this work, the temperature dependent electrical properties were investigated for bulk materials and thin films. An increase in the electrical conductivity until 100K is found through electron-impurity-scattering and a decrease at higher temperatures through electron-phonon-scattering for for films with a thickness of at least 150nm. The investigation of the thermal properties of -Ga2O3 show an anisotropy for the different crystal orientations with minimal primary axis values for the [100]-direction and maximal values for the [010]-direction. The temperature-dependence of the thermal properties shows a decease in conductivity and diffusivity for increasing temperature. For temperatures over 150K phonon-phonon-Umklapp-scattering can explain the measured values. For low temperatures phonon-impurity scattering is most likely the dominant scattering mechanism. A second investigated material class are kesterites. For this crystal structure two configurations were investigated, copper-zinc-tin-sulfide and copper-zinc-tin-selenide. The electrical properties show semiconducting characteristics with p-type conduction. The transport processes are defined through localised thermal activated tunneling within the band gap. Other reductions of the mobility are found by the crystalinity and the composition of the materials. The thermal properties show dominant phonon-phonon- Umklapp-scattering at higher temperatures and phonon-impurity-scattering for lower temperatures in a similar way as in beta-Ga2O3. This work shows new implemented measurement methods for investigating electrical and thermal properties as extentions to common methods.

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Qu, Yongtao. "Cu2ZnSn(S,Se)4 solar cells prepared from Cu2ZnSnS4 nanoparticle inks." Thesis, Northumbria University, 2015. http://nrl.northumbria.ac.uk/34222/.

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The selenisation of Cu2ZnSnS4 (CZTS) nanoparticle inks offers a potential low-cost route to the creation of Earth-abundant photovoltaic Cu2ZnSn(S,Se)4 (CZTSSe) thin film absorber layers. This work focuses on the properties of CZTS nanoparticles fabricated under different synthesis conditions, the selenisation kinetics and the performance of CZTSSe solar cell devices made using CZTS nanoparticle inks. Initially, CZTS nanoparticles were chemically synthesised via injection of sulphur into hot metallic precursors. Their composition, structural and optical properties were found to be sensitive to the reaction temperature, cooling rate and reaction time. For a reaction at 225 °C for 30 minutes followed by relatively slow cooling (~ 5 °C /min), it was possible to, facricate kesterite CZTS nanoparticles with an energy bandgap of 1.5 eV. CZTS nanoparticle inks have a strong effect on the performance of CZTSSe thin film solar cells. Specifically, longer reaction time of 60 minutes increased the device efficiency by increasing the concentration of acceptor levels to 5.3×1017 cm-3 in kesterite CZTSSe. Quenching the reaction rapidly (~ 20 °C/min) introduced wurtzite crystal structure and degraded the device efficiency from 5.4 % to 2.3 %. Increasing the reaction temperature to 255 °C resulted in the highest cell efficiency of 6.3 % despite the presence of secondary phase Cu2SnS3. In creating CZTSSe photovoltaic thin film absorber layers, high temperature selenisation of the CZTS nanoparticles plays a critical role in the formation of large grains. The results of a series of experiments indicate that the selenisation reaction is controlled by metal cation re-ordering and grain boundary migration (Avrami’s model), with a migration energy of 85.38 kJ/mol. Using a high selenium vapour pressure of 226 mbar during the selenisation process it was possible to achieve a device short circuit current density of 37.9 mA/cm2 resulting from increased carrier generation towards long wavelengths.

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Isotta, Eleonora. "Nanostructured thermoelectric kesterite Cu2ZnSnS4." Doctoral thesis, Università degli studi di Trento, 2021. http://hdl.handle.net/11572/315174.

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To support the growing global demand for energy, new sustainable solutions are needed both economically and environmentally. Thermoelectric waste heat recovery and energy harvesting could contribute by increasing industrial process efficiency, as well as powering stand-alone devices, microgenerators, and small body appliances.The structural complexity of quaternary chalcogenide materials provides an opportunity for engineering defects and disorder, to modify and possibly improve specific properties. Cu2ZnSnS4 (CZTS, often kesterite), valued for the abundance and non-toxicity of the raw materials, seems particularly suited to explore these possibilities, as it presents several structural defects and polymorphic phase transformations. The aim of this doctoral work is to systematically investigate the effects of structural polymorphism, disorder, and defects on the thermoelectric properties of CZTS, with particular emphasis to their physical origin. A remarkable case is the order-disorder transition of tetragonal CZTS, which is found responsible for a sharp enhancement in the Seebeck coefficient due to a flattening and degeneracy of the electronic energy bands. This effect, involving a randomization of Cu and Zn cations in certain crystallographic planes, is verified in bulk and thin film samples, and applications are proposed to exploit the reversible dependence of electronic properties on disorder. Low-temperature mechanical alloying is instead discovered stabilizing a novel polymorph of CZTS, which disordered cubic structure is studied in detail, and proposed deriving from sphalerite-ZnS. The total cation disorder in this compound provides an uncommon occurrence in thermoelectricity: a concurrent optimization of Seebeck coefficient, electrical and thermal conductivity. These findings, besides providing new and general understanding of CZTS, can cast light on profitable mechanisms to enhance the thermoelectric performance of semiconducting chalcogenides, as well as delineate alternative and fruitful applications.

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Isotta, Eleonora. "Nanostructured thermoelectric kesterite Cu2ZnSnS4." Doctoral thesis, Università degli studi di Trento, 2021. http://hdl.handle.net/11572/315174.

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To support the growing global demand for energy, new sustainable solutions are needed both economically and environmentally. Thermoelectric waste heat recovery and energy harvesting could contribute by increasing industrial process efficiency, as well as powering stand-alone devices, microgenerators, and small body appliances. The structural complexity of quaternary chalcogenide materials provides an opportunity for engineering defects and disorder, to modify and possibly improve specific properties. Cu2ZnSnS4 (CZTS, often kesterite), valued for the abundance and non-toxicity of the raw materials, seems particularly suited to explore these possibilities, as it presents several structural defects and polymorphic phase transformations. The aim of this doctoral work is to systematically investigate the effects of structural polymorphism, disorder, and defects on the thermoelectric properties of CZTS, with particular emphasis to their physical origin. A remarkable case is the order-disorder transition of tetragonal CZTS, which is found responsible for a sharp enhancement in the Seebeck coefficient due to a flattening and degeneracy of the electronic energy bands. This effect, involving a randomization of Cu and Zn cations in certain crystallographic planes, is verified in bulk and thin film samples, and applications are proposed to exploit the reversible dependence of electronic properties on disorder. Low-temperature mechanical alloying is instead discovered stabilizing a novel polymorph of CZTS, which disordered cubic structure is studied in detail, and proposed deriving from sphalerite-ZnS. The total cation disorder in this compound provides an uncommon occurrence in thermoelectricity: a concurrent optimization of Seebeck coefficient, electrical and thermal conductivity. These findings, besides providing new and general understanding of CZTS, can cast light on profitable mechanisms to enhance the thermoelectric performance of semiconducting chalcogenides, as well as delineate alternative and fruitful applications.

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Kattan, Nessrin. "Cu2ZnSnS4 nanoparticles : from structure to photovoltaic devices." Thesis, University of Bristol, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.702456.

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The need to resolve the energy shortage and environmental pollution leads to improving and exploiting thin films for photovoltaic (PV) applications. The current promising PV technologies are CdTe and CuInGaSe2 (CIGS), which have achieved high efficiencies and already reached the commercialisation stage. However, the scarcity of elements like indium and tellurium has limited the deployment of these technologies on a terawatt scale. A search for alternative materials has become crucial to replace and overcome current technology limitations. Copper zinc tin sulfide (Cu2ZnSnS4 or CZTS) has attracted a lot of attention as a potential alternative light-absorbing material that consists of abundant elements, non-toxic and inexpensive. Furthermore, CZTS has a direct band gap of 1.4-1.6 eV and high light absorption coefficient of 104 cm-1, which favourably matches the solar spectrum. CZTS material's have reached efficiencies up to 12.6%, as prepared by a hydrazine-based solution method. The danger of this reaction due to hydrazine auto-ignition temperature of 24°C and flash point of 38 °C makes this method unreliable for large-scale production. However, the efficiency gap between CZTS and CIGS is still large, with a conversion efficiency of around >22% for CIGS solar cells. CZTS shows lower open-circuit voltage, Voc, lower short-circuit current density, Jsc, and smaller minority-carrier lifetimes. These deficiencies could be related to the formation of defects in nanocrystals that cause trapping or recombination of carriers. This thesis aims to study the structure and defects in CZTS nanocrystals using transmission electron microscopy (TEM)-based techniques. The hot-injection method was used to synthesize CZTS due to the ability to produce large-scale and high-quality nanocrystals. In addition, CZTS nanoparticles growth was investigated after deposition on Molybdenum on glass substrate, providing annealing conditions that significantly improved grain growth to be suitable for PV applications. A detailed analysis of the CZTS crystal structure was undertaken, confirming a kesterite (tetragonal) structure of annealed CZTS nanocrystals. Furthermore, a fingerprint map for CZTS was obtained using selected area electron diffraction (SAED) and convergent beam electron diffraction (CBED). These techniques provide an approach enabling to distinguish CZTS from secondary phases such as ZnS that have a negative impact on the solar cell performance. Bright-field and dark-field were used to visualize the extended defects exhibited in nanocrystals. Nanocrystals showed that growth of defects in the form of lamellar twinning and dislocations occurred in the {112} planes, which are the preferential growth direction of annealed CZTS. The presence of these defects results in a local change to hexagonal phases in lamellar twinning boundaries. Moreover, high-angle annular dark field (HAADF) imaging was used to obtain high-resolution images of CZTS nanocrystals at a sub-O.l nm resolution that visualized the CZTS crystal unit cell, showing for the first time all atoms of Cu, Zn, Sn, and S are presented. These images allow to investigate the formation of antisite defects that have a significant impact on CZTS performance. These defects formed antisite domain boundaries that lie in different planes, causing disorder on the Cu, Zn, or Sn sites with some of the boundaries affecting local changes in stoichiometry. These studies can provide key information on the defects occurring at the atomic scale that have important consequences on CZTS devices' performance. The growth of nanocrystals 'on molybdenum substrates was also investigated to improve the grain size and the electronic properties of the material. An annealing condition is established that achieved a significant improvement in nanocrystals grain size from the initial average size of as-grown nanoparticles of ~7-12 nm up to 1 μm grain size. Annealing under hydrogen atmosphere with additional to SnS and S in a powder form was used to improve the nanoparticles growth. In addition to present a comparison of nanoparticles growth under other annealing conditions including nitrogen atmospheres and additional elements and binaries such as Na2S, SnS and S. The presence of hydrogen demonstrated an annealing atmosphere produces a significant improvement in nanocrystals growth compared with other annealing atmospheres. A promising efficiency is achieved for the CZTS solar cell of (0.8 %), Voc (253 mV), Jsc (6.84 mA/cm2), fill factor (FF) (45.9%), Rs (44.9 Ώ cm2), and Rsh (169.7 Ώ cm2) with a cell configuration (glass/Molybdenum/CZTS/CdS/intrinsic-ZnO)/Aluminum doped ZnO (AZO)/NiAl).

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Flammersberger, Hendrik. "Experimental study of Cu2ZnSnS4 thin films for solar cells." Thesis, Uppsala universitet, Fasta tillståndets elektronik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-139198.

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Cu2ZnSnS4 (CZTS) is a semiconductor with a direct band gap of about 1,5 eV and anabsorption coefficient of 10^4 cm^-1, and is for this reason a potential thin film solarcell material. Demonstrated efficiencies of up to 6,8% as well as use of cheap andabundant elements make CZTS a promising alternative to current solar cells.The aim of this study was to fabricate and characterize CZTS films and to evaluatetheir performance in complete solar cells. For the fabrication of CZTS we applied atwo-step process consisting of co-sputtering of the metal or metal-sulphurprecursors, and subsequent sulphurization by heating at 520°C in sulphur atmosphereusing sealed quartz ampoules.The work included a systematic comparison of the influence of composition on qualityand efficiency of CZTS solar cells. For this purpose films with various metallic ratioswere produced. The results show that the composition has a major impact on theefficiency of the solar cells in these experiments. Especially zinc-rich, copper-poor andtin-rich films proved to be suitable for good cells. The worst results were received forzinc-poor films. An increase in efficiency with zinc content has been reportedpreviously and was confirmed in this study. This can be explained by segregation ofdifferent secondary phases for off-stochiometric compositions. According to thephase diagram, zinc-poor films segregate mainly copper sulfide and copper tin sulfidecompounds which are conductive and therefore detrimental for the solar cell. Zincsulfide, that is supposed to be present in the other regions of the phase diagramexamined in this study, could be comparatively harmless as this secondary phase isonly isolating and by this ’just’ reduces the active area. This is less disadvantageousthan the shunting that can be caused by copper sulfides. Contrary to the efficiencyresults, metal composition had no major impact on the morphology.A comparison of the composition before and after the sulphurization revealed thatmetal precursors showed higher tin losses than sulphur containing precursors. Apossible explanations for this was given.Another central point of this work was the examination of the influence of sulphur inthe precursor. Less need of additional sulphur in the film might lead to better materialquality. This is based on the assumption that the film is subjected to less diffusion ofthe elements and so to less dramatic changes within the film, which might result infewer voids and defects. However, our experiments could find only a weak trend thatsulphur in the precursor increases the performance of the solar cells; concerningmorphology it was observed that more compact films with smaller grains developfrom metal-sulphur-precursors.The best efficiency measured within this work was 3,2%.

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Bais, Pierre. "Investigation cristallochimique avancée des composés photovoltaïques dérivés de Cu2ZnSnS4." Thesis, Nantes, 2017. http://www.theses.fr/2017NANT4046/document.

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Dans le domaine des cellules solaires de type couches minces, les composés dérivés de Cu2ZnSnS4 (CZTS) suscitent un intérêt croissant au fil des années. Grâce à un composé CZTS pauvre en Cu et pour lequel une partie du sélénium est substituée par du soufre, le rendement photovoltaïque maximal obtenu est de 12.6%. Plusieurs études suggèrent que des défauts de type Cu/Zn produisent un changement de la structure cristallographique la faisant passer de kësterite (groupe d’espace I4) à kësterite désordonnée (groupe d’espace I42m). Le désordre Cu/Zn ainsi que la distribution S/Se peuvent agir sur les performances des cellules solaires. L'objectif de cette thèse est l'étude approfondie de la structure des composés Cu2ZnSn(S,Se)4 (CZTSSe). Les échantillons étudiés ont été synthétisés par voie céramique et ont été caractérisés par les différentes techniques disponibles au laboratoire ainsi que par diffraction haute résolution et diffraction anomale sur monocristal au synchrotron SOLEIL. La combinaison de la diffraction des rayons-X, l’analyse élémentaire par dispersion d’énergie et la spectroscopie RMN ont permis d’en apprendre plus sur la structure et l’agencement des atomes en fonction du rapport S/(S+Se) ou de l’écart à la stoechiométrie CZTSSe. Les résultats principaux sont les suivants : les composés forment une solution solide de CZTSe à CZTS décrite dans la structure kësterite. De plus, bien qu’il soit possible d’observer des différences d’ordre à l’échelle locale, à longue distance, les anions et les atomes de cuivre et de zinc sont distribués aléatoirement, quelque soit le traitement thermique subi par l’échantillon ou l’écart à la stoechiométrie
Cu2ZnSnS4-derived compounds (CZTS) show an increasing interest in the field of low-cost thin film solar cells. The best solar energy conversion efficiencies of CZTS-based devices, up to 12.6%, are obtained for both copper-poor and mixed S/Se compounds. Several studies suggest that Cu/Zn antisite defects can occur, leading to the modification of the kësterite structure (space group I4) to the so-called disordered kesterite which is of higher symmetry (space group I42m). In the mixed S/Se compounds, the question of the cationic and anionic disorder is of high importance for solar cells efficiency and as not been already addressed through a crystal structure point of view. This study is dealing with a thorough chemical crystallographic investigation of Cu2ZnSn(S,Se)4 compounds. The studied compounds have been synthesized via a ceramic route and have been characterized by the use of different techniques available in the laboratory and also with the use of the high resolution powder diffraction as well as the anomalous single crystal diffraction at the Synchrotron SOLEIL. Thanks to the combination of X-ray diffraction, energy dispersive X-ray spectroscopy and NMR spectroscopy, transmission electronic microscopy, precise information about the structure and the microstructure as a function of S/(S+Se) ratio or the actual deviation from the 2:1:1:4 stoichiometry is provided. The existence of a full solid solution between CZTSe and CZTS with the full disordered kesterite structure is definitely demonstrated. However, at the local scale, there is a difference of order between compounds according to the cooling or to the stoichiometric deviation

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Teixeira, Jennifer Cláudia Passos. "Influência de parâmetros de crescimento nas propriedades de Cu2ZnSnS4." Master's thesis, Universidade de Aveiro, 2012. http://hdl.handle.net/10773/10131.

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Mestrado em Engenharia Física
Neste trabalho estudam-se filmes finos de Cu2ZnSnS4 (CZTS) no sentido de avaliar a influência dos parâmetros de crescimento na morfologia e nas propriedades estruturais e óticas destes filmes de forma a otimizar a sua utilização como camada absorvente em células solares. O número de períodos de precursores metálicos foi variado (1, 2, 4) e a sulfurização foi realizada em caixa de grafite ou em fluxo de enxofre. Os estudos realizados consistiram em análises morfológica, estrutural e ótica com base nas técnicas de SEM, EDS, XRD, espetroscopia de Raman e fotoluminescência. Verificou-se que as amostras sulfurizadas em fluxo de enxofre apresentavam um tamanho de grão médio superior ao observado para as amostras sulfurizadas em caixa de grafite. Adicionalmente, para este último conjunto de amostras, a intensidade da luminescência medida é claramente inferior à obtida para as amostras sulfurizadas em fluxo de enxofre. Por outro lado, o incremento do número de períodos de precursores revelou-se vantajoso tanto do ponto de vista do tamanho de grão como do incremento da razão sinal/ruído da luminescência. A análise estrutural permitiu verificar que a fase de CZTS é dominante em todas as amostras estudadas. Para a amostra com quatro períodos e sulfurizada em fluxo de enxofre, as dependências na potência de excitação e na temperatura permitiram estabelecer um modelo de transições radiativas entre um eletrão na banda de condução e um buraco ligado a um nível aceitador sob a influência de flutuações de potencial na banda de valência. A profundidade das flutuações de potencial na banda de valência foi avaliada, obtendo-se o valor de 104,7 0,4 meV. Foi estimada uma energia de ionização do nível aceitador de 78 3 meV e um valor para a energia de hiato do CZTS a 17 K na gama 1,467-1,507 eV. Os mecanismos de desexcitação não radiativa foram investigados tendo-se estabelecido dois canais envolvendo, um nível discreto ou uma banda. Os resultados deste trabalho revelaram-se importantes no processo de otimização das técnicas de crescimento em filmes finos de CZTS.
In this work we study Cu2ZnSnS4 (CZTS) thin films in order to evaluate the influence of the growth parameters on their morphology and structural and optical properties to optimize the application as absorbent layer in solar cells. The number of periods of metallic precursors was changed (1, 2, 4) and the sulphurization was done in a graphite box or under sulphur flux. The studies consisted of morphological, structural and optical analysis based on SEM, EDS, XRD, Raman spectroscopy and photoluminescence. It was found that the samples sulphurized in sulphur flux had an average grain size higher than that observed for the samples sulphurized in the graphite box. Additionally, the luminescence intensity for the last set of samples is clearly lower than the observed for the samples sulphurized in sulphur flux. Moreover, the increment in the number of periods of metallic precursors proved advantageous both from the viewpoint of grain size as the increase of signal/noise ratio of the luminescence. Structural analysis showed that the CZTS phase is dominant in all studied samples. For the sample with four periods and sulphurized on sulphur flux, the dependences of the emission on the excitation power and temperature allowed to establish a model of radiative recombination between an electron in the conduction band and a hole bound to an acceptor level under the influence of potential fluctuations of the valence band. The depth of the potential fluctuations in the valence band was evaluated, obtaining the value of 104,7 0,4 meV. An ionization energy for the acceptor level of 78 3 meV and a band gap at 17 K in the range 1,467-1,507 eV, were estimated. Two nonradiative channels involving, a discrete level or a band, were established. The results of this study have proved relevant in the optimization process of the growth of CZTS thin films.

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Fernandes, Paulo Alexandre Franco Ponte. "Células solares de Cu2ZnSnS4 por sulfurização de camadas metálicas." Doctoral thesis, Universidade de Aveiro, 2012. http://hdl.handle.net/10773/9755.

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Doutoramento em Física
As energias renováveis têm estado em destaque desde o fi nal do século XX. São vários os motivos para que isto esteja a acontecer. As previsões apontam para problemas de depleção das reservas de combustíveis fósseis, nomeadamente o petróleo e gás natural, durante o presente século. O carvão, ainda abundante, apresenta problemas ambientais signi cativos. Os perigos associados à energia nuclear estão fazer com que os governos de vários países repensem as suas políticas energéticas . Todas estas tecnologias têm fortes impactos ambientais. Considerando o conjunto das energias renováveis, a energia solar fotovoltaica tem ainda um peso menor no panorama da produção energética actual. A explicação para este facto deve-se ao custo, ainda elevado, dos sistemas fotovoltaicos. Várias iniciativas governamentais estão em curso, a SET for 2020 (UE) e a Sunshot (EUA), para o desenvolvimento de tecnologias que façam frente a este problema. A fatia de mercado que a tecnologia de filmes fi nos representa ainda é pequena, mas tem vindo a aumentar nos últimos anos. As vantagens relativamente à tecnologia tradicional baseada em Si são várias, como por ex. os custos energéticos e materiais para a fabricação das células. Esta dissertação apresenta um processo de fabricação de células solares em fi lmes finos usando como camada absorvente um novo composto semicondutor, o Cu2ZnSnS4, que apresenta como grande argumento, relativamente aos seus predecessores, o facto de ser constituído por elementos abundantes e de toxicidade reduzidas. Foi realizado um estudo sobre as condições termodinâmicas de crescimento deste composto, bem como a sua caracterização e das células solares finais. Este trabalho inclui um estudo dos compostos ternários, CuxSnSx+1 e compostos binários SnxSy, justi cado pelo facto de surgirem como fases secundárias no crescimento do Cu2ZnSnS4. Em seguida são descritos resumidamente os vários capítulos que constituem esta tese. No capítulo 1 é abordada de forma resumida a motivação e o enquadramento da tecnologia no panorama energético global. A estrutura da célula solar adoptada neste trabalho é também descrita. O capítulo 2 é reservado para uma descrição mais detalhada do composto Cu2ZnSnS4, nomeadamente as propriedades estruturais e opto-electrónicas. Estas últimas são usadas para explicar as composições não estequiométricas aplicadas no crescimento deste composto. São também descritas as várias técnicas de crescimento apresentadas na literatura. A última secção deste capítulo apresenta os resultados da caracterização publicados pelos vários grupos que estudam este composto. O método que foi implementado para crescer a camada absorvente, bem como os efeitos que a variação dos vários parâmetros têm neste processo são abordados no capítulo 3. Neste é também incluída uma descrição detalhada dos equipamentos usados na caraterização da camada absorvente e das células solares finais. As fases calcogêneas binária e ternárias são estudadas no capítulo 4. É apresentada uma descrição do método de crescimento, quer para as fases do tipo CuxSnSx+1, quer para as fases do tipo SnxSy e a sua caracterização básica, nomeadamente a sua composição e as propriedades estruturais, ópticas e eléctricas. No caso dos compostos binários são também apresentados os resultados de uma célula solar. No capítulo 5 são reportados os resultados da caracterização dos fi lmes de Cu2ZnSnS4. Técnicas como a dispersão Raman, a fotoluminescência, a efi ciência quântica externa e a espectroscopia de admitância são usadas para analisar as propriedades quer da camada absorvente quer da célula solar. No capítulo 6 é apresentada uma conclusão geral do trabalho desenvolvido e são referidas sugestões para melhorar e complementar os estudos feitos.
Renewable energy sources have been highlighted since the late twentieth century. There are several reasons why this is happening. Forecasts point to problems of depletion of fossil fuels, particularly oil and natural gas during the present century. Coal, still abundant, has a signi cant environmental problem. The dangers associated with nuclear power are making the governments of several countries to rethink their energy policies. All these technologies have strong environmental impacts. Considering the total renewable energy, photovoltaic is still a small player in the panorama of current energy production. The explanation is due to the fact that the cost of photovoltaic systems is still high. Several government initiatives are underway, like for instance the SET for 2020 (EU) and Sunshot (USA), for the development of technologies that solve this problem. The share of thin film technology is still small, but has increased in recent years. The advantages over traditional technology based on Si are various, eg. lower energy and materials costs to manufacture the cells. This dissertation presents a fabrication process of thin fi lm solar cells using as absorber layer a new semiconductor compound, Cu2ZnSnS4, which shows as major advantage compared with their predecessors, the fact that it consists of abundant elements with low toxicity. It is also presented a study on the growth conditions as well as the characterization of the absorber layer and fi nal solar cells. This work also include a study of ternary compounds, CuxSnSx+1 and binary compounds, SnxSy, justi ed by the fact that these phases arise as secondary phases in the growth of Cu2ZnSnS4. Next, the various chapters of this thesis are described brie y. In Chapter 1 is discussed brie y the motivation and framework technology in the global energy scenario. The solar cell structure adopted in this work is also described. Chapter 2 is allocated to a more detailed description of the compound Cu2ZnSnS4, namely, the structural and opto-electronic properties. The last ones are used to explain the non-stoichiometric compositions applied in the compound growth. It is also described the various growth techniques presented in the literature. The last section of this chapter shows the experimental results published by several groups studying this compound. The method implemented to grow the absorber layer, and the variation effects of the growth parameters are discussed in chapter 3. It is also included a detailed description of equipment used in characterization the absorber layer and the fi nal solar cells. The binary and ternary chalcogenide phases are studied in Chapter 4. It is presented a description of the growth method, for phases of the type CuxSnSx+1 and SnxSy and their basic characterization, namely the elemental composition, structural, optical and electrical properties. In the case of binary compounds is also shown the results of a solar cell. In the chapter 5 is reported the characterization results of the fi lms of Cu2ZnSnS4. Techniques such as Raman scattering, photoluminescence, the external quantum e ficiency and admittance spectroscopy are used to analyze the properties of both the absorber layer and the solar cell. In the chapter 6 is presented a general conclusion of the work developed during the project and some suggestions are also referred in order to complete and complement some of the studies.

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11

Malerba, Claudia. "Cu2ZnSnS4 thin films solar cells: material and device characterization." Doctoral thesis, Università degli studi di Trento, 2014. https://hdl.handle.net/11572/368186.

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Cu2ZnSnS4 (CZTS) quaternary compound has attracted much attention in the last years as new abundant, low cost and non-toxic material, with desirable properties for thin film photovoltaic (PV) applications. In this work, CZTS thin films were grown using two different processes, based on vacuum deposition of precursors, followed by a heat treatment in sulphur atmosphere. The precursors were deposited using two different approaches: (i) electron-beam evaporation of multiple stacks made of ZnS, Sn and Cu and (ii) co-sputtering deposition of the three binary sulphides CuS, SnS and ZnS. All the materials were characterized both as isolated films and as absorber layer in solar cells, produced using the typical structure Mo/CZTS/CdS/i:Zno/AZO. Both growth processes were found to give good quality kesterite films, showing CZTS as the main phase, large grains and suitable properties for PV application, but higher homogeneity and stoichiometry control were achieved using the co-sputtering route. A detailed investigation on CZTS optical properties, microstructure, intrinsic defect density and their correlation with the material composition is presented. A strong effect of the tin content on the bandgap energy, sub-gap absorption coefficient, crystalline domain and grain size is shown and a model based on the increase of the intrinsic defect density induced by a reduced tin content is proposed. These studies suggested a correlation between the increase of the bandgap energy and the improvement of the material quality, which was also confirmed by the performances of the final devices. CZTS thin films were then assembled into the solar cells and their properties as absorber layer were optimized by varying both composition and thickness. CZTS samples produced from stacked evaporated precursors allowed achieving a maximum efficiency of 3.2%, but reproducibility limits of the evaporation process made difficult to obtain further and rapid efficiency improvements. The co-sputtering route was demonstrated to be a more successful strategy, assuring a fine-control of the film composition with good process reproducibility. A fast improvement of solar cell efficiency was obtained using this approach and a maximum efficiency of 5.7% was achieved. The relationship between the absorber layer stoichiometry and the device performances was investigated: the effect of the Zn enrichment and a possible influence of the Cu/Sn ratio on the device performances are discussed. Investigation on CZTS/CdS and CZTS/MoS2 interfaces revealed that the optimization of both buffer-layer and back-contact technology is a primary need for further improvement of CZTS solar cells.

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12

Malerba, Claudia. "Cu2ZnSnS4 thin films solar cells: material and device characterization." Doctoral thesis, University of Trento, 2014. http://eprints-phd.biblio.unitn.it/1307/1/PhDThesis_C.Malerba.pdf.

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Cu2ZnSnS4 (CZTS) quaternary compound has attracted much attention in the last years as new abundant, low cost and non-toxic material, with desirable properties for thin film photovoltaic (PV) applications. In this work, CZTS thin films were grown using two different processes, based on vacuum deposition of precursors, followed by a heat treatment in sulphur atmosphere. The precursors were deposited using two different approaches: (i) electron-beam evaporation of multiple stacks made of ZnS, Sn and Cu and (ii) co-sputtering deposition of the three binary sulphides CuS, SnS and ZnS. All the materials were characterized both as isolated films and as absorber layer in solar cells, produced using the typical structure Mo/CZTS/CdS/i:Zno/AZO. Both growth processes were found to give good quality kesterite films, showing CZTS as the main phase, large grains and suitable properties for PV application, but higher homogeneity and stoichiometry control were achieved using the co-sputtering route. A detailed investigation on CZTS optical properties, microstructure, intrinsic defect density and their correlation with the material composition is presented. A strong effect of the tin content on the bandgap energy, sub-gap absorption coefficient, crystalline domain and grain size is shown and a model based on the increase of the intrinsic defect density induced by a reduced tin content is proposed. These studies suggested a correlation between the increase of the bandgap energy and the improvement of the material quality, which was also confirmed by the performances of the final devices. CZTS thin films were then assembled into the solar cells and their properties as absorber layer were optimized by varying both composition and thickness. CZTS samples produced from stacked evaporated precursors allowed achieving a maximum efficiency of 3.2%, but reproducibility limits of the evaporation process made difficult to obtain further and rapid efficiency improvements. The co-sputtering route was demonstrated to be a more successful strategy, assuring a fine-control of the film composition with good process reproducibility. A fast improvement of solar cell efficiency was obtained using this approach and a maximum efficiency of 5.7% was achieved. The relationship between the absorber layer stoichiometry and the device performances was investigated: the effect of the Zn enrichment and a possible influence of the Cu/Sn ratio on the device performances are discussed. Investigation on CZTS/CdS and CZTS/MoS2 interfaces revealed that the optimization of both buffer-layer and back-contact technology is a primary need for further improvement of CZTS solar cells.

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13

Handwerg, Martin [Verfasser], Saskia F. [Gutachter] Fischer, Susan [Gutachter] Schorr, and Marius [Gutachter] Grundmann. "Thermische und elektrische Eigenschaften der funktionellen Halbleiter beta-Ga2O3, Cu2ZnSnS4 und Cu2ZnSnSe4 / Martin Handwerg ; Gutachter: Saskia F. Fischer, Susan Schorr, Marius Grundmann." Berlin : Humboldt-Universität zu Berlin, 2019. http://d-nb.info/1195524439/34.

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14

Scragg, Jonathan James. "Studies of Cu2ZnSnS4 films prepared by sulfurisation of electrodeposited precursors." Thesis, University of Bath, 2010. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527514.

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Cu2ZnSnS4 (CZTS), being related to the highly successful Cu(In,Ga)(S,Se)2, and CuInS2 materials, is a promising candidate for thin film photovoltaic devices. It has the advantage that it contains no rare or expensive elements, and therefore has cost-reduction potential for commercial systems. A two-stage process for fabrication of CZTS films is presented, which consists of sequential electrodeposition of Cu, Sn and Zn layers followed by a heat treatment in the presence of S vapour (‘sulfurisation’). Electrodeposition conditions are developed to give uniform Cu|Sn|Cu|Zn precursors of controlled morphology and composition, by the use of a rotating disc electrode system. Precursors are converted to CZTS by sulfurisation in the presence of elemental S, using a rapid thermal processing system (RTP). The sulfurisation reaction is studied by XRD and Raman spectroscopy as a function of temperature and at short time intervals, and a sequence of reactions is derived for the formation of CZTS. It is shown that the sulfurisation reaction occurs within minutes above 500°C. A model is presented for film formation when rapid heating rates are employed. The effects of sulfurisation time, background pressure and precursor composition on the morphological and structural properties of the CZTS films are investigated. Observations of grain size changes and compositional modification are made and explained in terms of the likely secondary phases present. The opto-electronic properties of the CZTS films are measured using a photoelectrochemical technique. Changes in the external quantum efficiency and band gap are studied as a function of sulfurisation parameters and precursor composition. After crystallisation of the CZTS phase during sulfurisation, the photocurrent obtained from the films continued to rise upon heating in the absence of S, which is explained by changes in acceptor concentration. Large shifts in the band gap are seen, and some proposals are made to explain the behaviour. The observations are discussed in the context of the particular compositions and sulfurisation conditions routinely used in the CZTS literature, and recommendations are made for further work.

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15

Choubrac, Léo. "Cristallochimie de composés dérivés de Cu2ZnSnS4 pour des applications photovoltaïques." Nantes, 2014. https://archive.bu.univ-nantes.fr/pollux/show/show?id=67905501-3436-41fa-8cc8-7fbe0e136902.

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Les performances des dispositifs photovoltaïques en couches minces utilisant les dérivés de Cu2ZnSnS4 (CZTS) comme absorbeur sont fortement dépendantes des propriétés cristallochimiques de ce matériau. En particulier les composés plus pauvres en cuivre et plus riches en zinc sont connus pour être les plus efficaces, et le désordre structural comme un frein à l’obtention de hauts rendements. L’étude de ces composés préparés par voie solide a permis d’établir un diagramme de phases qui révèle deux types de substitution distincts. La structure de ces composés a ensuite été étudiée à l’échelle de la maille par des méthodes cristallographiques (diffraction des rayons X sur poudre, monocristal, en conditions conventionnelles et anomales), et à celle de l’atome par RMN du solide (65Cu, 67Zn, 119Sn). La combinaison de ces techniques permet de décrire ces mécanismes de substitution et d’établir une corrélation entre composition, conditions de synthèse et désordre structural. Ensuite, la spectroscopie Raman - largement répandue et utilisable avec des matériaux déposés en couches minces- a été utilisée comme outil de caractérisation. Enfin, une large partie de ces résultats ont pu être étendus aux composés homologues séléniés (dérivés de Cu2ZnSnSe4)
The photovoltaic performances of Cu2ZnSnS4 derivatives (CZTS)-based thin film solar cells are strongly dependant of the crystallochemistry properties of this material. Particularly, the copper-poor zinc-rich compounds are widely known to be the most efficient, and the structural disorder as a brake on growth of the efficiencies. A large set of CZTS compounds have been synthesized by solid state route. The study of these compounds permits us to determine a phase diagram which reveals two distinct type of substitution. Then we lead a structural investigation, at the scale of the cell with XRD methods (on powders and single crystals, and on classical as well as on resonant conditions), and at the atomic scale with solid state NMR of 65Cu, 67Zn and 119Sn. The combination of these techniques allows describing these substitution mechanisms and finally a relationship between composition, synthesis conditions and structural disorder. Then, Raman spectroscopy – as a common and thin-film suitable method – has been use as a characterization tool. Finally, a large part of these results have been extended to the homologue selenide compounds (Cu2ZnSnSe4 derivatives)

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Malaquias, João Corujo Branco. "Cu2ZnSnS4 thin films for PV: comparison of two growth methods." Master's thesis, Universidade de Aveiro, 2010. http://hdl.handle.net/10773/3498.

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Mestrado em Engenharia Física
This work focuses on a comparison between Cu2ZnSnS4 thin films with precursors grown exclusively by evaporation or by evaporation and RF Magnetron Sputtering. On the films which were grown using the second method was either sputtered ZnS or elemental Zinc. The morphology and composition of the samples was studied by SEM/EDS and their structure by XRD. Both methods were successful in producing thin films containing Cu2ZnSnS4. The samples which had their precursors grown exclusively through evaporation exhibited the most compact morphology but also were the ones that had more undesirable crystalline phases. Regarding the remaining samples, in the case where elemental Zinc was sputtered no diffusion issues were observed, whereas the ones with ZnS presented a layer of this material on the surface. This report is divided into six chapters which contain the introduction, information relative to semiconductors, Cu2ZnSnS4 solar cells, the growth and characterization techniques, the experimental procedure, results and their analysis and ends with the conclusion.
Com o presente trabalho pretende-se efectuar uma comparação entre filmes finos de Cu2ZnSnS4 cujos precursores foram crescidos exclusivamente por evaporação ou por evaporação e pulverização catódica RF com magnetrão. A morfologia e composição das amostras foram estudadas por SEM/EDS e a sua estrutura por DRX. Com ambos os métodos conseguiu-se crescer filmes finos de Cu2ZnSnS4. As amostras cujos precursores foram crescidos exclusivamente através de evaporação apresentavam uma morfologia mais compacta, contudo eram as que apresentavam maior número de fases cristalinas indesejadas. Relativamente às restantes amostras, no caso em que Zinco foi depositado por pulverização catódica, não foram observados problemas de difusão, contudo o mesmo não se verificou para as que continham ZnS, sendo que estas apresentavam uma camada deste material na superfície dos filmes. Este documento encontra-se dividido em seis capítulos que incluem a introdução, informação relativa a semicondutores, células solares de Cu2ZnSnS4, as técnicas de crescimento e caracterização, o procedimento experimental, os resultados e a sua análise e termina com a conclusão.

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Sousa, Marco António Neves de. "Estudo de Cu2ZnSnS4 obtido através de precursores metálicos e binários." Master's thesis, Universidade de Aveiro, 2012. http://hdl.handle.net/10773/11002.

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Mestrado em Engenharia Física
presente dissertação tem como objetivo o estudo, de filmes finos de (CZTS) a partir de precursores elementares e binários. O trabalho aqui apresentado encontra-se dividido em duas partes. Na primeira parte foram crescidos nas mesmas condições dois filmes de CZTS com precursores elementares (cobre, , zinco, e estanho, ) e sulfurizados num forno tubular. Posteriormente foram analisados, morfológica e estruturalmente, tendo-se verificado a existência de CZTS e de fases secundarias. Concluiu-se que os filmes são idênticos pelo que o processo de produção é reprodutível. Na segunda parte foram crescidos dois filmes de CZTS com precursores binários (sulfureto de cobre, , sulfureto de estanho e zinco elementar) e sulfurizados num forno tubular, onde no primeiro filme apenas se fez uma análise de concentrações de composição e no segundo foi feito um ajuste das condições de deposição com base na primeira. Nesta parte apenas se fez a análise estrutural do segundo filme revelando a presença de CZTS e de fases secundárias de CTS. Este último foi dividido em 3 partes que foram sujeitas a tratamentos químicos diferentes: um com cianeto de potássio (KCN), um com ácido clorídrico (HCl) e outro com ambos os tratamentos. Seguidamente com estes foram preparadas células fotovoltaicas. A caracterização elétrica mostrou que apenas a célula feita com base no CZTS sujeito ao tratamento com HCl apresentou uma eficiência significativa de 0,4%. Por fim foi crescido um novo filme através de precursores binários e sulfurizado por processamento térmico rápido (RTP). Este último foi dividido em duas partes em que uma das partes foi sujeita a um tratamento de HCl. De seguida foram preparadas duas células fotovoltaicas. A caracterização elétrica mostrou que apenas a célula com o tratamento de HCl apresentou uma eficiência de 2,5%. Esta dissertação está dividida em oito capítulos: Introdução, Princípios básicos de uma célula solar, , Técnicas de crescimento e caracterização do CZTS, Crescimento dos filmes finos de CZTS, Caracterização e discussão dos resultados, Conclusões e Bibliografia.
The present dissertation, aims for the study of (CZTS) thin films from elemental and binary precursors. The work here presented is divided into two parts. In the first part, were grown, under the same conditions, two CZTS films with elemental precursors (copper, , zinc and tin, ) and sulfurized in a tubular furnace. Subsequently analysed, morphologic and structurally, having verified the existence of CZTS and secondary phases. It was concluded that the films are identical so that the production process is reproducible. In the second part, were grown two CZTS films of binary precursors (copper sulphide, and tin sulphide, and elemental zinc), and sulfurized in a tubular furnace, where in the first film only had a compositional analysis of concentrations and in the second one an adjustment was made based on the first deposition. In this part only structural analysis for second film was made revealing the presence of CZTS and secondary phases of CTS. The latter was divided into 3 parts which have been subjected to different chemical treatments: one with potassium cyanide (KCN), hydrochloric acid (HCl) and another with both treatments. Next with these, photovoltaic cells were prepared. The electric characterization showed that only the cell made based on CZTS subjected to treatment with HCl showed a significant efficiency of 0,4%. Finally a new film was grown by binary precursors and sulphurised by rapid thermal processing (RTP). Next two photovoltaic cells were prepared. The electric characterization showed that only the cell with the HCl treatment showed an efficiency of 2,5%. This dissertation is divided into eight chapters: Introduction, Basic principles of a solar cell, , Growth techniques and Characterization of CZTS, Growth of CZTS thin films, Characterization and discussion of results, Conclusions and Bibliography

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18

Carlhamn, Rasmussen Liv. "Evaluation of Cu2ZnSnS4 Absorber Films Sputtered from a Single, Quaternary Target." Thesis, Uppsala universitet, Institutionen för kemi - Ångström, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-199838.

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Cu2ZnSnS4 (CZTS) is a promising absorber material for thin-film solar cells since it contains no rare or toxic elements, has a high absorption coefficient and a near ideal bandgap energy. It does, however, present some challenges due to the limited single-phase region of the desired kesterite phase and its instability towards decomposition. Sputtering of CZTS from quaternary, compound targets using RF magnetron sputtering is known. In this thesis work CZTS absorbers were made using pulsed DC magnetron sputtering on stainless steel substrates. The effects of varying substrate temperature and adding seed layers to promote grain growth were investigated, as well as the effects of a rapid thermal anneal in a S-rich atmosphere. Film compositions determined by X-ray fluorescence were found to be inside or close to the kesterite single-phase region in the phase diagram, but were generally too Cu-rich and Zn-poor to yield good results. The kesterite phase was confirmed with X-ray crystallography and Raman spectroscopy, indicating that it is possible to sputter CZTS from a single target with a high deposition rate. It was found that Cu2S seed layers could induce a significant increase in grain size, and preliminary experiments showed no evidence of the seed layer remaining after deposition of the absorber. Higher substrate temperatures also lead to increased grain size, but excessive heating caused the decomposition of the CZTS. Annealing induced grain growth, relaxed internal stress in the material and improved the electrical properties of the CZTS films, primarily by the removal of shunts.

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19

Fontané, Sánchez Xavier. "Caracterización por espectroscopia Raman de semiconductores Cu2ZnSnS4 para nuevas tecnologías fotovoltaicas." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/134930.

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El trabajo se ha centrado en el análisis del compuesto Cu2ZnSnS4 (CZTS) mediante la técnica de espectroscopia de dispersión Raman, para una mayor optimización de los procesos de crecimiento de capas absorbedoras y la fabricación de celdas fotovoltaicas. Inicialmente, se da una visión del panorama actual del mercado de la energía fotovoltaica, con especial énfasis en destacar las diferentes tecnologías utilizadas en la fabricación de celdas solares. Dentro de estas tecnologías, el estudio se centra en el uso del compuesto CZTS, ya que se trata de un semiconductor con interesantes propiedades optoelectrónicas que está constituido por elementos muy abundantes en la corteza terrestre y de nula toxicidad, lo que lo convierte en un candidato especialmente adecuado para el desarrollo de tecnologías fotovoltaicas sostenibles y de producción a gran escala. Dado que la gran mayoría de experimentos presentados en este trabajo son de espectroscopia Raman, también hay una breve introducción a la teoría de dispersión inelástica de la luz y al efecto Raman en sí. También se describen las diferentes configuraciones experimentales llevadas a cabo durante la tesis, se muestra el equipamiento utilizado en los experimentos y se introduce el concepto de la espectroscopia Raman-Auger, presentando un primer experimento efectuado sobre una capa de CIGSe. En un intento de profundizar en el conocimiento de las propiedades vibracionales del Cu2ZnSnS4 como paso previo a la caracterización del compuesto, se ha recopilado la información disponible en las referencias bibliográficas actuales sobre la estructura cristalina del material y se ha realizado una serie de análisis de espectroscopia Raman: en primer lugar se ha analizado una capa de referencia de CZTS con diferentes configuraciones de polarización para establecer los modos de simetría, y posteriormente se ha procedido a la identificación de los picos Raman. Dicha identificación se ha realizado mediante diferentes longitudes de onda de excitación para activar de forma más o menos efectiva los distintos modos de vibración. Por último se han estudiado los efectos debidos al desorden y los defectos estructurales. Como consecuencia de la cantidad de elementos involucrados en el compuesto de CZTS y la complejidad de las reacciones de formación implicadas, es esperable la aparición de fases secundarias binarias de Cu/Zn/Sn-S y ternarias de Cu-Sn-S. Dada la gran relevancia que tienen dichas fases secundarias en las propiedades optoelectrónicas de los dispositivos, se ha desarrollado una metodología para su determinación, haciendo especial hincapié en la identificación de estas fases secundarias mediante la excitación selectiva en condiciones de pre-resonancia y argumentando el uso de la espectroscopia Raman por encima de otras técnicas de caracterización más comunes como la difracción de rayos X (XRD). Por último, se ha implementado todo lo estudiado anterior para una serie de capas de CZTS ricas en Zn de grado fotovoltaico, que han sido preparadas por sulfurización de stacks metálicos y analizadas mediante combinación de técnicas de XRD y espectroscopias Raman y Auger. A partir de los resultados obtenidos del análisis en profundidad de las capas para diferentes valores de tiempo y temperatura de recocido, se ha propuesto una reacción de formación del CZTS.
The present work has been focused on the analysis of Cu2ZnSnS4 compound (CZTS) using Raman scattering spectroscopy, for further optimization of the processes and manufacturing absorber layers for solar cells. After a brief overview of the current market landscape in photovoltaics, the study focuses on the use of CZTS compound, an earth-abundant and non-toxic semiconductor. There is also a brief introduction to the theory of inelastic scattering of light and Raman effect, the description of the different experimental configurations performed during the thesis and the equipment used. A series of Raman spectroscopy analysis of Cu2ZnSnS4 compound have been performed: first, a reference CZTS layer has been analyzed with different polarization configurations to establish the symmetry modes, followed by Raman peak identification. Such identification was carried out by different excitation wavelengths to activate the different vibrational modes. Finally, it has been studied the effects due to disorder and structural defects. As a consequence of the number of elements involved in the CZTS compound and the complex forming reactions involved, it is expected the presence of secondary binary phases (Cu / Zn / Sn-S) and ternary Cu-Sn-S. Due to the high relevance that these secondary phases have in the optoelectronic properties of the devices, it has been developed a methodology for determining these phases, with particular emphasis on their identification by selective excitation in pre-resonance conditions. Finally, a series of Zn-rich CZTS photovoltaic grade layers have been implemented by sulfurization of metal stacks, and analyzed by XRD, Raman spectroscopy and Raman/Auger combined technique. The formation reaction of CZTS compound has been proposed from the results of the in-depth analysis of the layers for different values of annealing time and temperature.

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Опанасюк, Анатолій Сергійович, Анатолий Сергеевич Опанасюк, Anatolii Serhiiovych Opanasiuk, Олександр Ігорович Гузенко, Александр Игоревич Гузенко, Oleksandr Ihorovych Huzenko, Олександр Анатолійович Доброжан, et al. "Чорнила на основі наночасток Ag, ZnO, Cu2ZnSnS4 для друку електронних схем." Thesis, Сумський державний університет, 2018. http://essuir.sumdu.edu.ua/handle/123456789/67837.

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Останнім часом виготовлення елементів побуту переходить від адитивного методу виробництва до формування цілісного об’єкта методом 3D друку. Це пов’язано з тим, що цей метод дає змогу здешевити і пришвидшити виробництво, а в подальшому перенести виготовлення нескладних предметів побуту безпосередньо в людські домівки. Технологія друку чорнилами на основі наночастинок металів та напівпровідників дає змогу швидко та дешево створювати електричну розводку і напівпровідникові елементи приладів сенсорики, прозорої електроніки та геліоенергетики.

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Tiong, Vincent Tiing. "Hydrothermal synthesis and characterisation of Cu2ZnSnS4 light absorbers for solar cells." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/78636/1/Vincent%20Tiing_Tiong_Thesis.pdf.

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This project has extended the knowledge in the hydrothermal synthesis of copper zinc tin sulphide (CZTS) semiconductor material which is regarded as one of the most promising light absorbing material for PV technologies. The investigation of various reaction parameters on the controlled synthesis of CZTS compound has provided important insight into the formation mechanism as well as the crystal growth behaviour of the material. CZTS nanocrystals with different crystal structure and particle size were synthesised throughout this project. The growth mechanism of CZTS crystals through a high temperature annealing treatment was also explored.

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Доброжан, Олександр Анатолійович, Александр Анатольевич Доброжан, Oleksandr Anatoliiovych Dobrozhan, Анатолій Сергійович Опанасюк, Анатолий Сергеевич Опанасюк, Anatolii Serhiiovych Opanasiuk, H. Cheong, and D. Nam. "Raman spectroscopy of nanocrystalline Cu2ZnSnS4 thin films obtained by pulsed spray pyrolysis." Thesis, Львівський національний університет ім. Івана Франка, 2015. http://essuir.sumdu.edu.ua/handle/123456789/46447.

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The sprayed CZTS thin films were deposited using an aqueous solution containing CuCl2·2H2O (0.02 M), ZnCl2 (0.01 M), SnCl2·2H2O (0.015 M) and SC(NH2)2 (0.1 M) at the temperature substrate of 400 0C with the different values of starting solution volume per sample (2 ml, 3 ml, 4 ml, 5 ml).

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Monahan, Bradley Michael. "Synthesis and Characterization of Phase-pure Copper Zinc Tin Sulfide (Cu2ZnSnS4) Nanoparticles." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1404732007.

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24

Ericson, Tove. "Reactive sputtering and composition measurements of precursors for Cu2ZnSnS4 thin film solar cells." Licentiate thesis, Uppsala universitet, Fasta tillståndets elektronik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-208543.

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Cu2ZnSnS4 (CZTS) is a thin film solar cell material that only contains abundant elements and for which promising conversion efficiencies of 9.2 % have been shown. In this thesis composition measurements and reactive sputtering of precursors for CZTS films have been studied. These precursors can be annealed to create high quality CZTS films. Accurate control and measurement of composition are important for the synthesis process. The composition of a reference sample was determined using Rutherford backscattering spectroscopy. This sample was thereafter used to find the composition of unknown samples with x-ray fluorescence measurements. Pros and cons with this approach were discussed. The reactive sputtering process, and the resulting thin films, from a CuSn- and a Zn-target sputtered in H2S-atmosphere were investigated and described. A process curve of the system was presented and the influence of sputtering pressure and substrate temperature were examined. The pressures tested had little influence on the film properties but the substrate temperature affected both composition and morphology, giving less Zn, Sn and S and a more oriented film with increasingly facetted surface for higher temperatures. The precursors produced with this method are suggested to have a disordered phase with randomized cations, giving a CZTS-like response from Raman spectroscopy but a ZnS-pattern from x-ray diffraction measurements. The films have an excellent homogeneity and it is possible to achieve stoichiometric sulfur content. The complete steps from precursors, to annealed films, to finished solar cells were investigated for three controlled compositions and three substrate temperatures. The films sputtered at room temperature cracked when annealed and thus gave shunted solar cells. For the samples sputtered at higher temperatures the trend was an increased grain size for higher copper content and increased temperature. However, no connection between this and the electrical properties of the solar cells could be found.

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Доброжан, Олександр Анатолійович, Александр Анатольевич Доброжан, Oleksandr Anatoliiovych Dobrozhan, Петро Сергійович Данильченко, Петр Сергеевич Данильченко, Petro Serhiiovych Danylchenko, Анатолій Сергійович Опанасюк, Анатолий Сергеевич Опанасюк, Anatolii Serhiiovych Opanasiuk, and H. Cheong. "Structural and optical features of Cu2ZnSnS4 films deposited by pulsed spray pyrolysis technique." Thesis, Vasyl Stefanyk Precarpathian National University, 2017. http://essuir.sumdu.edu.ua/handle/123456789/65509.

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The goal of work – the investigation of morphological, structural, optical properties and elemental composition of CZTS thin films obtained by pulsed spray pyrolysis at a different volume of a sprayed initial precursor.

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26

Stroyuk, Oleksandr, Alexandra Raevskaya, Oleksandr Selyshchev, Volodymyr Dzhagan, Nikolai Gaponik, Dietrich R. T. Zahn, and Alexander Eychmüller. "“Green” Aqueous Synthesis and Advanced Spectral Characterization of Size-Selected Cu2ZnSnS4 Nanocrystal Inks." Macmillan Publishers Limited, 2018. https://tud.qucosa.de/id/qucosa%3A33825.

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Structure, composition, and optical properties of colloidal mercaptoacetate-stabilized Cu2ZnSnS4 (CZTS) nanocrystal inks produced by a “green” method directly in aqueous solutions were characterized. A size-selective precipitation procedure using 2-propanol as a non-solvent allows separating a series of fractions of CZTS nanocrystals with an average size (bandgap) varying from 3 nm (1.72 eV) to 2 nm (2.04 eV). The size-selected CZTS nanocrystals revealed also phonon confinement, with the main phonon mode frequency varying by about 4 cm−1 between 2 nm and 3 nm NCs.

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Frisk, Christopher. "Modeling and electrical characterization of Cu(In,Ga)Se2 and Cu2ZnSnS4 solar cells." Doctoral thesis, Uppsala universitet, Fasta tillståndets elektronik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-320308.

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In this thesis, modeling and electrical characterization have been performed on Cu(In,Ga)Se2 (CIGS) and Cu2ZnSnS4 (CZTS) thin film solar cells, with the aim to investigate potential improvements to power conversion efficiency for respective technology. The modeling was primarily done in SCAPS, and current-voltage (J-V), quantum efficiency (QE) and capacitance-voltage (C-V) were the primary characterization methods. In CIGS, models of a 19.2 % efficient reference device were created by fitting simulations of J-V and QE to corresponding experimental data. Within the models, single and double GGI = Ga/(Ga+In) gradients through the absorber layer were optimized yielding up to 2 % absolute increase in efficiency, compared to the reference models. For CIGS solar cells of this performance level, electron diffusion length (Ln) is comparable to absorber thickness. Thus, increasing GGI towards the back contact acts as passivation and constitutes largest part of the efficiency increase. For further efficiency increase, majority bottlenecks to improve are optical losses and electron lifetime in the CIGS. In a CZTS model of a 6.7 % reference device, bandgap (Eg) fluctuations and interface recombination were shown to be the majority limit to open circuit voltage (Voc), and Shockley-Read-Hall (SRH) recombination limiting Ln and thus being the majority limit to short-circuit current and fill-factor. Combined, Eg fluctuations and interface recombination cause about 10 % absolute loss in efficiency, and SRH recombination about 9 % loss, compared to an ideal system. Part of the Voc-deficit originates from a cliff-type conduction band offset (CBO) between CZTS and the standard CdS buffer layer, and the energy of the dominant recombination path (EA) is around 1 eV, well below Eg for CZTS. However, it was shown that the CBO could be adjusted and improved with Zn1-xSnxOy buffer layers. Best results gave EA = 1.36 eV, close to Eg = 1.3-1.35 eV for CZTS as given by photoluminescence, and the Voc-deficit decreased almost 100 mV. Experimentally by varying the absorber layer thickness in CZTS devices, the efficiency saturated at <1 μm, due to short Ln, expected to be 250-500 nm, and narrow depletion width, commonly of the order 100 nm in in-house CZTS. Doping concentration (NA) determines depletion width, but is critical to device performance in general. To better estimate NA with C-V, ZnS and CZTS sandwich structures were created, and in conjunction with simulations it was seen that the capacitance extracted from CZTS is heavily frequency dependent. Moreover, it was shown that C-V characterization of full solar cells may underestimate NA greatly, meaning that the simple sandwich structure might be preferable in this type of analysis. Finally, a model of the Cu2ZnSn(S,Se)4 was created to study the effect of S/(S+Se) gradients, in a similar manner to the GGI gradients in CIGS. With lower Eg and higher mobility for pure selenides, compared to pure sulfides, it was seen that increasing S/(S+Se) towards the back contact improves efficiency with about 1 % absolute, compared to the best ungraded model where S/(S+Se) = 0.25. Minimizing Eg fluctuation in CZTS in conjunction with suitable buffer layers, and improving Ln in all sulfo-selenides, are needed to bring these technologies into the commercial realm.

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Hreid, Tubshin. "Co-electrodeposition of Cu-Zn-Sn film and synthesis of Cu2ZnSnS4 photovoltaic material." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/94160/12/Tubshin%20Hreid%20Thesis.pdf.

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This work contributes to electrochemical fabrication of Cu-Zn-Sn alloy thin film and synthesis of kesterite Cu2ZnSnS4 film which is a promising new material for sustainable photovoltaic devices. Co-electrodeposition provides a low-cost, time-saving and environmentally friendly approach to fabricate Cu-Zn-Sn film and has a potential application in large scale and high throughput production of Cu2ZnSnS4 material. This work includes identification of critical parameters controlling the formation of homogeneous Cu-Zn-Sn film, investigation of its growth mechanism, precisely controlled synthesis of kesterite Cu2ZnSnS4 film and effects of metal ions concentration on formation of Cu-Zn-Sn film and its application in kesterite Cu2ZnSnS4 solar cells.

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Khoshsirat, Nima. "Investigation of the doping effect on Cu2ZnSnS4 thin film properties for photovoltaic applications." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/130700/1/Nima_Khoshsirat_Thesis.pdf.

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The aim of this research is to increase the efficiency of thin film solar cells made by Copper, Zinc, Tin and Sulfur (CZTS). By including a small amount of chromium in the absorber layer has improved dramatically the light absorption of CZTS films in the infrared region, making use of a portion of solar spectrum never accessed before. This study revealed that a 4% Cr concentration produced a 90% increase in the efficiency, due to a double step absorption of low energy photons. These findings open the way to highly efficient CZTS solar cells.

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Quennet, Marcel [Verfasser]. "First Principles Calculations for the Semiconductor Material Kesterite Cu2ZnSnS4 and Se-containing Derivatives / Marcel Quennet." Berlin : Freie Universität Berlin, 2016. http://d-nb.info/1122438850/34.

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Zhang, Shengli. "Study the growth process and interface properties of Cu2ZnSnS4 solar cells fabricated by magnetron sputtering." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/123667/1/Shengli_Zhang_Thesis.pdf.

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In this project, solar cells made from earth abundant materials, Copper-Zinc-Tin-Sulfide were fabricated. Several new strategies were developed to boost the energy conversion efficiency, including a high conductive and transparent ITO window layer prepared at low temperature for CZTS solar cells, a novel precursor stacking and optimised sulphurisation process, and interface engineering by introducing ultra-violet generated ozone treatment. With all these efforts, efficiency of above 5.5% for pure CZTS was achieved.

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32

Tablaoui, Meftah. "Développement de matériaux massifs appartenant au système chalcopyrite pour des applications photovoltaïques." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10073/document.

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Dans le domaine du photovoltaïque, le composé Cu2ZnSnS4 (CZTS) serait une solution alternative aux composés classiques en couches minces qui sont à base d'éléments chers ou toxiques. Mise à part un gap de 1.5 eV et un coefficient d'absorption de 10-4 cm-1, il est constitué d'éléments bénins et abondants, ce qui réduira le coût de revient de la cellule finale. Il connaît un intérêt particulier et bien qu'il ait atteint un rendement de 12.6%, il demeure méconnu quant à l'effet de ses propriétés intrinsèques sur ses performances photovoltaïques. En raison de la volatilité du soufre, des déviations à la stoechiométrie peuvent être enregistrées rendant la synthèse d'un monophasé très difficile. Les phases secondaires sont difficilement inévitables, elles constituent une barrière à la formation de la phase CZTS, ce qui rend difficile la fixation du gap et augmente le taux de recombinaison des porteurs de charges. Dans le cadre de cette thèse, une série de composés CZTS a été synthétisée par réaction à l'état solide et liquide avec des excès en soufre pour compenser les pertes liées à la décomposition chimique et l'évolution de la composition dans le diagramme de phase Cu-Zn-Sn-S. L'effet du souffre sur la cristallinité, la pureté et l'ordre dans la maille a été mis en évidence. Le domaine monophasé a été déterminé et il a été montré qu'il est possible d'obtenir des composés de grande pureté. La morphologie par microscopie optique a révélé des polycristaux granulaires avec rejet des phases secondaires dans les joints de grains. Le composé Cu2ZnGeS4 (CZGS) pourrait trouver des applications dans le photovoltaïque et l'optoélectronique. L'ajout de l'étain pourrait sensiblement améliorer la cinétique réactionnelle et la cristallinité d'où l'intérêt d'étudier le composé Cu2ZnGexSn(1-x)S4 ( x=0 à 1). L'analyse cristallographique par DRX a montré une transition structurale d'une kesterite pour CZTS vers une orthorhombique pour CZGS. Le composé Cu2Zn(Ge,Sn)S4 est une solution solide avec gap de miscibilité entre 0 et 20% de germanium
In the photovoltaic field, Cu2ZnSnS4 (CZTS) compound is an alternative solution to substitute solar thin film based on toxically and expensive conventional materials. The gap of this material is around 1.5eV and absorption coefficient 10-4 cm-1, in addition this material is composed of abundant and harmless elements which will strongly decrease the price of the final cell. This material present a particular interest and in spite of the efficiency which reached 12.6%, till now this material is not well known especially the effect of its intrinsic properties on its photovoltaic performances. Because of the sulfur volatility, it is difficult to prepare single phase compound. Also, it is difficult to surmount the formation of secondary phases which are a barrier to CZTS complete reaction allowing difficulties to fix the gap and increase the recombination of carrier. In the frame of this PhD thesis, a serial of CZTS compounds has been synthetized from solid and liquid state using an excess of sulfur to compensate its volatility and the composition change in the Cu-Zn-Sn-S equilibrium diagram. We have determined the monophased field and we have shown that it is possible to obtain a compound with high purity. By optical microscopy we have observed a granular morphology composed of polycrystalline grains and the secondary phases were rejected in the grains boundary. The Cu2ZnGeS4 (CZGS) compound can be used for photovoltaic and optoelectronic applications. The addition of tin can be a good way to improve the kinetic reaction and the crystallinity of this materials, So, it is interesting to study Cu2ZnGexSn(1-x)S4 ( x=0 to 1) compound . By X ray diffraction we have shown a structure transition from Kesterite (CZTS) to orthorhombic (CZGS). The Cu2Zn(Ge,Sn)S4 compound is a solid solution with a gap miscibility between 0 and 20% of germanium

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Hutchings, K. D. "High throughput combinatorial screening of Cu-Zn-Sn-S thin film libraries for the application of Cu2ZnSnS4 photovoltaic cells." Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/8771.

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The naturally occurring mineral of Cu2ZnSnS4 (CZTS) is a promising alternative absorber layer for thin film based photovoltaic devices. It has the remarkable advantage that it consists of abundant, inexpensive and non-toxic elements compared to its crystallographically related and highly successful counterparts: the Cu(In,Ga)(S,Se)2 (CIGSSe) and CuIn(S, Se)2 (CISSe) material systems. Therefore, there is real commercial potential for reduced material costs and improved device efficiencies. A two-stage high throughput combinatorial process for the fabrication of Cu-Zn-Sn-S thin film libraries is presented, which consists of either sequentially stacking or co-depositing Cu,Sn and Zn precursor layers by DC magnetron sputtering followed by a sulphurisation process. Sputtering conditions and target-substrate geometry are developed to give compositionally graded Cu-Zn-Sn precursor layers spanning a wide spatial region around the point of stoichiometry. Conversion into Cu-Zn-Sn-S libraries is achieved by thermally evaporating a uniform layer of sulphur directly onto the metal alloy and annealing the sample at 500 °C in a furnace. Effects of the precursor composition on the structural properties of the films prior to the incorporation of sulphur are investigated. The sulphurised libraries are then studied by Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy as a function of composition, to assess the effects on morphology and phase formation. Observations of changes in lattice parameters and crystallinity are clear. The opto-electronic and electrical properties of the CZTS film libraries are measured using photoconductivity and hot point probe techniques, respectively. Changes in the band gap and conductivity type are studied as a function of atomic ratios. Based on high performing compositions, devices have been fabricated with the highest achieving cell at 1.26 %. The observations are discussed in the context of the particular compositions and synthesis conditions, and recommendations are made for further work.

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Bourlier, Yoan. "Etude de films minces de CuInS2, CuIn1-xGaxS2, et Cu2ZnSnS4, élaborés par voie sol-gel, destinés aux applications photovoltaïques." Thesis, Lille 1, 2013. http://www.theses.fr/2013LIL10004/document.

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Ce travail de recherche porte sur l’élaboration et la caractérisation de films minces photo-absorbants de CuInS2, CuIn1-xGaxS2, et de Cu2ZnSnS4 destinés aux applications photovoltaïques. Les films minces ont été préparés par voie sol-gel puis déposés par enduction centrifuge sur substrat de silicium ou de verre. Les sols, formés à partir d’acétates métalliques et d’alcanolamines, ont été étudiés par spectroscopie IR, viscosimétrie et ATD-ATG. Les paramètres de dépôts des sols, et les traitements de calcination, ont ensuite été optimisés. Des films d’oxydes multi-couches, sans fissuration, et de faibles rugosités ont ainsi été élaborés. Une dernière étape de sulfuration des films d’oxydes a été effectuée afin de former les composés souhaités. Les films sulfurés ont fait l’objet d’une étude approfondie par DRX, EDX, MEB, AFM, spectroscopie UV-VIS-nIR et mesures par effet Hall. Leurs structures, leurs morphologies, mais aussi leurs propriétés optiques et électriques ont ainsi pu être étudiées. L’interface des films de CuInS2 avec le film de Mo, utilisé comme contact ohmique arrière de la cellule solaire, a également été étudiée par micro-EDX à l’aide d’analyses MET. Les résultats obtenus montrent que le procédé sol-gel, bien que très peu développé dans le domaine des cellules photovoltaïques, est une voie de synthèse bien adaptée à l’élaboration de films minces à structure chalcopyrite et kësterite. Ces résultats sont très prometteurs pour la réalisation d’une cellule solaire par voie sol-gel
This research activity concerns the elaboration and characterization of photo-absorbing thin films of CuInS2, CuIn1-xGaxS2, and Cu2ZnSnS4 devoted to photovoltaic applications. The thin films were prepared by sol-gel process and deposited by spin-coating technique on silicon and glass substrates. The sols, synthesized from metallic acetates and alcanolamines, were studied by IR-spectroscopy, viscosimetry, and TDA-TGA. The deposition parameters of the sols, and the calcination treatments were then optimized. The multi-layers oxides films produced were obtained without cracks and with low roughness. The last step was to produce the desired compounds through the sulfurization of the oxides films. The sulfurized films were studied by XRD, EDX, SEM, AFM, UV-VIS-nIR spectroscopy, and Hall Effect measurements. Their structures, morphologies, as well as their optical and electrical properties have been investigated. The interface between CuInS2 films and Mo film, defined as a back-contact of the solar cell, was also studied by micro-EDX with TEM analysis. Despite the fact that sol-gel process is not well-developed in the photovoltaic field, the obtained results show that sol-gel process is a well-adapted technique for elaboration of thin films with chalcopyrite and kesterite structures. These results are very promising for the achievement of a sol-gel solar cell

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Schutz, Priscila. "Obtenção por electrospinning e tratamento térmico em ar de sulfeto de cobre, zinco e estanho (CZTS) e sua caracterização microestrutural e de propriedades fotofísicas." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/101196.

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O objetivo deste estudo foi a síntese de Cu2ZnSnS4 (CZTS) por electrospinning, sem a etapa de sulfurização e com tratamento térmico em atmosfera ambiente. A solução precursora consistiu na dissolução dos sais dos metais de interesse: tiourea como fonte de enxofre e polivinil butiral (PVB) em etanol como polímero condutor. Esta solução foi submetida ao processo de electrospinning com uma tensão elétrica de 16 kV e uma distância entre coletor e capilar de 120 mm e fluxo de 3 mL/h. O efeito da temperatura de tratamento térmico sobre a formação do CZTS foi investigada. Para isso, o material resultante do processo de electrospinning foi tratado termicamente em diferentes temperaturas: 150°C durante 72h, 150°C durante 24h mais 300°C durante 24h, 300°C durante 48h, 400°C durante 1h, 450°C durante 1h, 500°C durante 1h e 550°C durante 1h. A taxa de aquecimento foi de 0,5°C/mim. A Influência do agente complexante dietanolamina (DEA) sobre as propriedades do material formado, quando adicionado à dolução precursora, foi também investigada. As amostras resultantes destes tratamentos térmicos foram caracterizadas através de análises térmicas (ATG), difração de raios X (DRX), espectroscopia Raman, microscopia eletrônica de varredura (MEV/EDS), microscopia eletrônica de transmissão (MET) e, por medidas ópticas (UV-Vis) e espectroscopia de reflectância difusa (ERD). Foram obtidos filmes homogêneos e compactos com uma espessura de aproximadamente 10 nm. Os resultados indicaram que foi obtida fase CZTS a 400°C, com as razões S/(Cu+Zn+Sn) = 1,1, Cu/(Zn+Sn) = 0,8 e Zn/Sn = 1,26. No entanto, a presença de algumas fases secundárias elevou o band gap para aproximadamente 2,2 eV. Além disso, foi verificado que a adição de DEA na solução precursora não aumenta a qualidade do CZTS formado por electrospinning.
The aim of this work was to study the production of CZTS by electrospinning method without sulfurization process and in-air heat treatment. The precursor solution was prepared by dissolving metal salts, tiourea as a sulfur source and PVB as conductive polymer. The resulting solution was electrospun onto a cylindrical target with an electric voltage of 16 kV at a 120 mm distance and flow rate of 3 mL/h. The effect of in-air heat treatment in the phase formation and morphology of electrospun CZTS fibers were investigated by the following conditions, 150°C for 72h, 150°C for 24h plus 300°C for 24h, 300°C for 48h, 400°C for 1h, 450°C for 1h, 500°C for 1h e 550°C for 1h, with a used a heating rate of 0.5°C.min-1 The Influence of the addition of complexing agent diethanolamine (DEA) on the properties of the final material was investigated. The samples were characterized by thermal analysis (TGA), R-X diffraction, scanning electron microscopy (SEM/EDS), transmission electron microscopy and optical measurements (UV-Vis). The results show the obtainment of a well crystallized CZTS phase with the heat treatment of 400°C with ratios S/(Cu+Zn+Sn) =1.1, Cu/(Zn+Sn) = 0.8 e Zn/Sn = 1.26. Homogeneous and compact films with the morphology of 10 nm spheres were found in this study. However, the presence of some secondary phases increases the band gap to approximately, 2.2 eV. Furthermore, it was found that the addition of DEA in the precursor solution does not increase the quality of CZTS formed by electrospinning.

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Gillorin, Arnaud. "Synthèse et caractéristiques de nanoparticules de Cu2MSnS4 (M = Co, Zn, Fe,. . ) pour application photovoltaïque." Toulouse 3, 2010. http://www.theses.fr/2010TOU30183.

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Les matériaux Cu2MSnS4 (M= Co, Zn, Fe,. . ) à largeur de bande interdite d'environ 1. 5 eV et constitués d'éléments abondants et peu onéreux dans la nature présentent une forte potentialité comme films minces absorbants de cellules photovoltaïques. Parmi les voies proposées pour la fabrication de films minces d'épaisseur d'environ 3 µm, la voie encres de nanoparticules a récemment été validée avec la fabrication de cellules possédant des rendements de conversion de l'ordre de 10%. Cette thèse décrit la synthèse et la caractérisation de trois générations de nanoparticules de Cu2MSnS4 (M= Co, Zn, Fe,. . ). La première génération de nanoparticules a été obtenue par une approche synthèse solvothermale mettant en œuvre des précurseurs variés. Les conditions d'obtention de particule de taille nanométrique ont été définies après rationalisation des conditions de formation de la structure Cu2MSnS4, effectuée dans divers solvants. Une seconde génération de nanoparticules, à haut degré de cristallisation est proposée, mettant en œuvre un procédé à haute température. Enfin la troisième génération concernant des nanoparticules de très faible taille, inférieure à 4 nm et possédant des propriétés optoélectroniques de confinement quantique a été explorée via un procédé de peptisation
In the context of the potential large scale deployment of terrestrial photovoltaic, it is important to address the issue of sustainability and costs of raw materials for device manufacture. A promising candidate for low cost absorber layer is the quaternary compound Cu2ZnSnS4 (Czts) which is an analogue of Cuins2 obtained by replacing In(II) by Zn(II) and Sn(IV). Czts is one of the promising materials for low cost thin film solar cell, because of a suitable band gap energy of 1. 4-1. 5 ev and the large absorption coefficient over 10'4 CM-1. To replace potentially more expensive vaccum based techniques, "ink"-based approach has been developed. A family of nano-crystals inks was developed (Cu2CoSnS4, Cu2ZnSnS4, Cu2FeSnS4. . . ) displaying various primary crystallite sizes and morphologies and involving three different process routes performed at different temperatures. Benefits of the high temperature route (T=500°C) compared to the low temperature route (T=200°C) are illustrated from tem, xrd and raman spectroscopy results. Three generations of Cu2CoSnS4 nanoparticles were designed possessing various mean sizes (3 Nm, 150 Nm and 200 Nm) and different degree of crystallization

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Доброжан, Олександр Анатолійович, Александр Анатольевич Доброжан, Oleksandr Anatoliiovych Dobrozhan, Станіслав Ігорович Кахерський, Станислав Игоревич Кахерский, Stanislav Igorevich Kakherskyi, Анатолій Сергійович Опанасюк, Анатолий Сергеевич Опанасюк, and Anatolii Serhiiovych Opanasiuk. "The effect of low-temperature annealing treatments on the structure and chemical composition of CU2ZNSNS4 films deposited onto flexible polyimide substrates." Thesis, Ivan Franko National University of Lviv, 2020. https://essuir.sumdu.edu.ua/handle/123456789/80969.

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38

Oftinger, Frédéric. "Mise en forme et frittage de couches minces Cu2ZnSnS4 pour la conversion photovoltaïque à partir de nanoparticules déposées par voie liquide." Toulouse 3, 2013. http://www.theses.fr/2013TOU30184.

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Un matériau prometteur à base d'éléments matériaux abondants dans la nature et peu toxiques, le Cu2ZnSnS4 (CZTS) a récemment fait l'objet d'une attention particulière. Parallèlement, un nouveau procédé de mise en forme mettant en œuvre des dispersions de nanoparticules (impression de nanoparticules) couplé à une cuisson de type céramique. Avec comme objectif le développement de cellules solaires bas cout, nous avons proposé un procédé de fabrication de nanoparticules de Cu2ZnSnS4 (CZTS) re-dispersable en milieu solvant, sans surfactant mettant en œuvre une source de sulfure commerciale, la thiourée. Cette source de sulfure présente l'avantage d'agir comme i) agent complexant limitant la croissance des cristallites de CZTS ii) agent de surface permettant l'obtention de dispersions en milieu de faible force ionique et en solvant polaire iii) complexant transitoire facilement substituable par un agent de surface exempt de carbone. Des dispersions fortement concentrées (c > 100 g·l-1 en CZTS) stables dans l'éthanol ont ainsi été obtenues après échange par des anions S2-. Des films de nanoparticules de CZTS ont été élaborées par trempé. Une procédure permettant l'obtention de films sans fissuration d'épaisseur 3 µm, épaisseur requise pour l'obtention de films de CZTS de haute performance, a été mise au point mettant en œuvre. Le frittage de ces films a été réalisé sous pression partielle de sélénium dans des technologies de frittage conventionnelles ou en technologie frittage ultra-rapide. Un frittage convenable a été obtenu à 550 °C pendant 15 minutes avec conversion presque complète du CZTS en CZTSe montrée par diffraction des rayons X ou par spectroscopie Raman. La faible concentration en défauts optoélectroniques de ces films frittés a été mise en évidence par photoluminescence. Une cellule solaire Mo/CZTSe/CdS/ZnO a été fabriquée
Copper-Zinc-Tin chalcogenide (Cu2ZnSnS4, CZTS) materials have attracted increasing attention for solar cell absorber layers. In contrast to well-known solar absorber materials for thin films chalcogenide-based solar cells such as Cu(In,Ga)(S,Se)2 and CdTe, CZTS is composed of abundant and non-toxic elements. Alternately, nanoparticles ink printing route process has been recently developed to address the issue of fabrication costs, replacing potentially more expensive vacuum based techniques. With the objective to develop low cost solar cells, we have designed a process route for the fabrication of solvent-redispersible, surfactant-free Cu2ZnSnS4 (CZTS) nanoparticles with the objective to take benefit of a simple sulfide source (thiourea) which advantageously act as (i) a complexing agent inhibiting crystallite growth (ii) a surface additive providing redispersion in low ionic strength polar solvents (iii) a transient ligand easily replaced by an carbon-free surface additive. Highly concentrated (c > 100 g·l-1), stable, ethanolic CZTS dispersions were achieved after S2- surface exchange. CZTS nanoparticle films on Mo Glass substrate were fabricated using dip coating as a film forming process route. A procedure yielding crack-free films of 3 µm required for enhanced photovoltaic performances was defined involving a multi-step deposition. Sintering of these nanoparticle films under selenium partial pressure was carried out by conventional and rapid thermal processing sintering. A reasonable sintering of the films was achieved at 550 °C during 15 min with nearly complete conversion of the CZTS into CZTSe as shown by XRD and Raman spectroscopy. The good electronic properties and low defect concentration of the sintered, crack-free CZTSe films resulting from these building blocks was shown by photoluminescence investigation, making these CZTS building blocks interesting for low-cost, high performance CZTSe solar cells. A solar cell (Mo/ CZTSe/CdS/ZnO) was fabricated

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39

Dufton, Jesse T. R. "Computational studies of sulphide-based semiconductor materials for inorganic thin-film photovoltaics." Thesis, University of Bath, 2013. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607142.

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New thin-film solar cell materials and a greater understanding of their properties are needed to meet the urgent demand for sustainable, lower-cost and scalable photovoltaics. Computational techniques have been used to investigate Cu2ZnSnS4, CuSbS2 and CuBiS2 , which are potential absorber layer materials in thin-film photovoltaics. Their low cost, low toxicity and their constituent’s relative abundance make them suitable replacements for current thin-film absorbers, which are CdTe or Cu(In, Ga)(S, Se)2 based systems. Firstly, we have used hybrid Density Functional Theory (DFT) calculations to study CuSbS2 and CuBiS2. We calculate band gaps of 1.69 eV and 1.55 eV respectively, placing CuBiS2 within the optimal range for a viable absorber material. The density of states for both these materials indicate that formation of electron hole charge carriers will occur in the Cu d10 band. Consequently, photoexcitation leads to the oxidation of Cu(I). Secondly, we have derived interatomic potentials which describe the complex structure of Cu2ZnSnS4 accurately. We find that the Cu/Zn antisite defect represents the lowest energy form of intrinsic defect disorder. For these antisite defects, we find a preference for small neutral defect clusters, which suggests a degree of self-passivation exists. Investigations of Cu-ion transport find VCu migration is possible via a vacancy hopping mechanism. There are pathways which can be connected to give 3D long-range diffusion. Investigations of the Cu/Zn site disorder in Cu2ZnSnS4 find that configurations which are kesterite-like will dominate synthetic samples. However, perfectly ordered kesterite will not be formed due to entropic effects. The simulations indicate the stannite and stannite-like polymorphs are less favourable, and can only account for ≈2.5% of a sample. Investigations of the surfaces of Cu2ZnSnS4, suggest that the vast majority of the low index surfaces are dipolar and that only the (1 1 2), (0 1 0) and (1 0 1) surfaces have low surface energies.

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40

Sagna, Alphousseyni. "Etude et élaboration par Close-Spaced Vapor Transport (CSVT), d’absorbeurs Cu2ZnSnS4 en couches minces polycristallines destinées à la réalisation de photopiles à faible coût." Thesis, Perpignan, 2016. http://www.theses.fr/2016PERP0035/document.

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Le kësterite Cu 2 ZnSnS 4 (CZTS) est un semi-conducteur de type p composé d'éléments abondants et non toxiques. Ces atouts, en plus d’un gap direct, compris entre 1,45 et 1,5 eV, en font un excellent candidat pour remplacer les matériaux Cu(In,Ga)Se 2 et CdTe utilisés dans les photopiles en couches minces. Il a cependant été mis en évidence que les performances des photopiles utilisant CZTS comme absorbeur souffrent de la présence de phases secondaires dans les couches minces. Ainsi le travail présenté dans cette thèse décrit le dépôt de couches minces de CZTS par un procédé simple et à faible coût appelé Close SpacedVapor Transport(CSVT). Son objectif essentiel est de réaliser un composé CZTS dépourvu de toute phase secondaire en vue d’améliorer les rendements de conversion des cellules photovoltaïques à base de CZTS. Pour cela, le matériau massif a d’abord été synthétisé sous forme de lingot par le refroidissement lent et programmé d’un bain fondu obtenu à partir d'éléments purs. Les caractérisations réalisées sur le massif montrent qu’il s’agit d’un composé monophasé Cu 2 ZnSnS 4 , de composition quasi-stœchiométrique, dans la structure kësterite. Le lingot broyé et mis sous forme de pastille, est utilisé par la suite comme source à évaporer dans un réacteurCSVT utilisant de l’iode comme agent de transport, pour la formation de couches minces CZTS. L'optimisation des paramètres clés de dépôt des couches minces que sont la température du substrat et la pression d'iode a été effectuée. Les résultats d'analyses menées sur les couches de CZTS déposées à des températures de substrat comprises entre 460 à 500 °C, sous des pressions d'iode de 2 Kpa à 4 kPa, ont révélés d’excellentes propriétés physico-chimiques
The kësterite Cu 2 ZnSnS 4 (CZTS) is a p-type semiconductor material made from abundant and nontoxic chemical elements. These advantages in addition to a direct band gap, with energy between 1.45eV and 1.5 eV, make it an excellent candidate for replacement of Cu(In, Ga)Se 2 and CdTe absorber layers currently used in thin film solar cells. It has although been highlighted that photovoltaic devices based on thin CZTS absorber layers are highly suffering from the presence of secondary phases in the thin films. So the work presented in this thesis describes thin CZTS layers deposition by a simple and low-cost process called Close Spaced Vapor Transport (CSVT). Its main objective is to realize a CZTS compound free of any secondary phase with the aim of improving conversion efficiencies of CZTS thin films based photovoltaic solar cells. For this purpose, the bulk CZTS material was first synthesized in the form of ingot by a slow cooling of a molten stoichiometric mixture of pure elements. Characterizations realized on this bulk material showed that it relates to a single phase, quasi-stoichiometric Cu 2 ZnSnS 4 compound in the kësterite structure. The ingot was milled into powders and pressed to give 1 mm thick pellets. These pellets were therefore used as evaporating sources in a CSVT reactor with iodine as transport agent, for the thin CZTS layers deposition. Optimizations of the key deposition parameters that are substrate temperature and iodine pressure were performed. The Results of the investigations conducted on the CZTS layersdeposited at substrate temperature in the range 460 °C-500 °C, under iodine pressure in the order of 2 kPa to 4 kPa, revealed excellent physico-chemical properties

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41

Chen, Hsuan-Fu, and 陳宣甫. "Synthesis and Characterizations of Cu2ZnSnS4 and Au/Cu2ZnSnS4 Nanocrystals." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/15752217288817879945.

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碩士
輔仁大學
化學系
101
Quaternary chalcogenides, such as Cu(In,Ga)Se2, Cu(In,Ga)S2, Cu2ZnSnSe4, and Cu2ZnSnS4 have recently spurred broad interest owing to their unique properties, namely large extinction coefficient (> 104 cm-1)and ideal band gap energy (~ 1.5 eV) for photovoltaic devices, thus showing great potential in solar energy converting devices, e.g., solar cells and photodetectors. Among the aforementioned materials, Cu2ZnSnS4 (CZTS), comparing with other quaternary semiconductors, holds the advantages of earth-abundant (Zn, Sn versus In, Ga ) and non-toxic (S versus Se) elements, hence making Cu2ZnSnS4 one of the most prominent candidates in manufacturing cost-effective as well as environmentally benign devices. Herein we report the synthesis and structural investigation of core-shell type Au@CZTS nanocrystal. The presence of metal core could help both the formation of CZTS shell and the photoelectric properties of the core-shell nanocomposites. The obtained nanocrystals show enhanced conductivity under illumination of light, indicating the promising applicability in the field of solar energy converting devices.

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42

JIANG, GUAN-TING, and 江冠霆. "Preparation of Cu2ZnSnS4 Target for RF Sputtering Deposition of Cu2ZnSnS4 Solar Cell Materials." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/47441565661055115009.

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碩士
國立高雄海洋科技大學
微電子工程研究所
105
In recent years, global warming and the depletion of fossil fuels have made green energy more and more important. Solar energy is one of the important green energy sources. It is clean and inexhaustible making it being a promising alternative energy source. In this study, Cu2ZnSnS4 (CZTS) was chosen as the theme. It is a kind of P-type direct energy gap semiconductor. Zinc and tin are abundant in the Earth making CZTS a low-cost material. Sulfur is non-toxic and high absorption coefficient. CZTS has an energy gap of 1.4~1.6 eV which is suitable for use as solar cell absorbent layers with high efficiency of solar conversion. In this study, CZTS target powder was prepared by sol-gel method. The CZTS powder was sulfurized to enhance its quality. A high quality CZTS sputtering target was prepared by pressing the CZTS powder into bulk. Sputtering method has following advantages: (1) strong adhesion, (2) suitable for high melting point substances, (3) large area deposition, and (4) reactive deposition. Higher quality CZTS solar cell thin films can be prepared by RF sputtering by exactly controlling RF power and pressure. Therefore, this study combined with the advantages of sol-gel for synthesizing CZTS powder and RF plasma sputtering method for depositing CZTS solar cell film. The properties of CZTS such as crystal structure, surface morphology, element composition, energy gap, electrical analysis, etc., were analyzed by X-ray diffract-meter (XRD), Raman spectra, field emission gun scanning electron microscope (FE-SEM), energy dispersive spectrometer (EDS), α-step, UV-visible spectroscopy (N & K) and Hall measurement. In this study, the CZTS powder with Kesterite structures was confirmed by XRD analysis. As CZTS films were deposited at 35 W and 20 mtorr, a significant Raman shift of CZTS was confirmed at 336 cm-1. Its resistance coefficient is 7.69×10-2 ohm-cm, and absorption coefficient is over than 104 cm-1. Its energy gap is ~1.34 eV which makes it suitable for using as solar cell absorption layers.

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43

Yang, Jyun-rong, and 楊濬嵘. "Preparation of Cu2ZnSnS4 nanofibers by Electrospinning." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/69708495415678622097.

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碩士
國立臺南大學
綠色能源科技研究所碩士班
101
Quaternary kesterite-type Cu2ZnSnS4 (CZTS) nanofibers for low-cost thin film solar cells were successfully synthesized by a relatively simple electrospinning process. Semiconductor CZTS nanofibers were obtained from CA/CZTS precursor after annealing treatment at 450℃ for 3h. CZTS nanofibers were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). The optical properties of the CZTS nanofibers were also recorded by UV-vis absorption spectroscopy. The results showed that the synthesized CZTS nanofibers had a single phase, good crystallinity and a stoichiometric composition. Moreover, the prepared nanofibers had a size ranging from 200-500 nm and a band gap of 1.46 eV, which demonstrates that they are suitable for use in a thin film solar cell light absorption material.

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44

Chen, Kuan-Yuan, and 陳冠沅. "Preparation of CZTS (Cu2ZnSnS4) solar cell nanomaterials." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/t56jsv.

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碩士
國立高雄海洋科技大學
微電子工程研究所
103
In recent years, the effect of gradually exhausted resources make people gradually aware of environmental protection and green energy development. Many countries actively search for renewable energy to reduce the environmental damage. Therefore, solar energes with inexhaustible and clean characteristics become the most potential of green energy. Therefore in this thesis, the study on Cu2ZnSnS4 (CZTS) solar cell material will be presented. Cu2ZnSnS4 is a p-type direct band gap semiconductor material. Its band gap value is suitable as absorption layers in thin film solar cells. Its constituent element of zinc and tin has higher content in the earth, and sulfur is relatively non-toxic. These make it suitable for thin-film solar cells. In this work, CuZnSn (CZT) thin film was prepared by DC sputtering and then via sulfurization process to synthesis CZTS thin film. Sputtering method has advantage of good adhesion, high efficiency and low pollution. Sputtering power, working pressure and sulfurization period were adopted for the CZTS analysis parameters. The results show that the CZTS film has better crystalline characteristics with increase of sputter pressure and sulfurization time. Better crystalline CZT were obtained at the optima processes of sputtering power of 60W, process pressure of 12mtorr and sulfurization for 30 min. The sulfurization CZTS exhibits Kesterite crystal structure with energy gap of 1.4 ~ 1.6eV, and its chemical constituent are closer to the stoichiometry value. In addition to sputtering preparation of CZTS , we also prepare CZTS nanopowder by microwave hydrothermal. The obtained CZTS nanopowder was used for co-catalyst of NaTaO3 to increase photocatalyst properties. Finally, this study presents a sol-gel process of Cu2ZnSnS4 solar cell and its I-V characteristics.

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Huang, Cheng-Fu, and 黃丞甫. "Synthesis and Reaction Mechanism of Cu2ZnSnS4 Powders." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/94660431561479346539.

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碩士
國立中興大學
材料科學與工程學系所
100
Cu2ZnSnS4 (CZTS) powders have been synthesized from aqueous solutions consisting of copper (II) chloride, zinc (II) chloride, stannic (IV) chloride, and thioacetamide (TAA) dissolved in mixtures of deionized water and ethanol. The CZTS powders were obtained when the precursor solutions were held isothermally at 65 oC followed by annealing at 550 oC in Ar atmosphere. When the reaction temperature was held at 35 to 55 oC, a pronounced formation of intermediate Cu3(TAA)3Cl3 prisms resulted which produced Cu2S at elevated temperatures as an impurity. In addition, rounded particles were obtained from the CZTS precursor solutions by filtering removal of the Cu3(TAA)3Cl3 prisms. Since Zn was present as Zn2+ ions in the reaction solution, Cu2SnS3 (CTS) resulted rather than the formation of CZTS when the rounded particles were annealed at 450 ¬oC. Therefore, a successful synthesis of the CZTS powders requires annealing of the solution containing Zn2+ and the precipitate in the same pot. From thermal analyses, crystalline CZTS powders began to form as the annealing temperature was raised above 210 oC. XRD pattern revealed that the CZTS diffraction peaks appeared when the annealing temperature was raised to 250 oC and no other phases were observed. We have also conducted separate experiments involving CuCl2, ZnCl2, SnCl4, CuCl2+ZnCl2, CuCl2+SnCl4 mixture with the TAA respectively and reacted isothermally at 65 oC for 1 h. After the reaction, the solutions were annealed at 190 oC and 250 oC, respectively. When the annealing temperature was increased, following reaction steps resulted: (1) Cu2+ ions were firstly reduced to Cu+ which facilitated Cu2S formation；(2) (NH4)2ZnCl4 → ZnS；(3) (NH4)2SnCl6 → SnS2. The Cu2S reacted with SnS2 to form CTS first, and then CTS reacted with ZnS to form the CZTS powders.

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46

Lin, Tsungi, and 林宗義. "A Study of Cu2ZnSnS4 (CZTS) Thin Films." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/26608162022594312730.

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碩士
國立高雄海洋科技大學
微電子工程研究所
100
Since the industrial revolution, people relies the energy living the lives of both rich and comfortable, nothing more than oil, coal, natural gas, but these are limited fossil energy. When using fossil energy in the human from head to foot, along with air pollution, environmental damage, and even serious ecological changes and other issues, so starting alternative energy sources (such as nuclear, wind, hydro, solar, etc.) studies, in which solar energy everywhere available, the most popular non-polluting natural energy. Compared to the high-cost of high-efficiency solar cells, the use of compound semiconductor solar cells, light weight and low cost to achieve the effect of copper and zinc tin sulfide (Cu2ZnSnS4, CZTS) film as a p-type direct bandgap semiconductor, has a non-toxic materials adequate sources of such advantages, so this paper focuses on the CZTS thin-film production. The CZTS thin-film prepared by sol-gel method, and for different process conditions which are different crystallized temperatures (160℃~260℃) and different sulfured temperatures (300℃~400℃). Finally, we discuss the CZTS thin-film's material properties and composition analyses such as XRD, Raman, EDX, SEM etc. It's with the strong XRD peaks when CZTS crystallization temperature at 260 ℃ and sulfured temperature at 350 ℃, in XRD peaks (112) 28.5 °, (220) 47.3 °, (312) 56.1 °. And Raman measurement is about 315.77 (cm-1) performances.

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CHEN, CHUN-YU, and 陳俊宇. "Synthesis and Characterization of Solution-Processed Cu2ZnSnS4 Absorber." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/81536662799363979809.

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碩士
大葉大學
電機工程學系
102
In this study, sol-gel the preparation of copper zinc tin sulfide (Cu2ZnSnS4, CZTS) coating solution, then spin-coating deposited on molybdenum glass substrate as thin film solar cell absorber layer, and pass into hydrogen sulfide gas mixture (5% H2S in Nitrogen) thermal annealing to reduce the lattice structure CZTS sulfur film defects. The buffer layer by chemical bath deposition (CBD) of CdS thin film, and finally a transparent conductive layer (ZnO: Al) by sputtering, the production of thin film solar cell CZTS. This study focused on: (1) different cadmium/sulfur ratio and the mixed solvent (ethanol) to explore the different processes for CdS buffer layer film properties affected; (2) changing the Sulfurization temperature for CZTS and collecting impact layer characteristics; (3) optimum Sulfurization temperature, the sol-gel process to explore different solvent composition for CZTS absorber layer characteristics and effects of thin film solar cells prepared photovoltaic efficiency. The experimental results showed that: (1) cadmium/sulfur ratio of film 1/5, the homogeneous nucleation reaction prone to make large particles in solution among, the cadmium/sulfur ratio of the film 1/10, the significantly less homogeneous nucleation reaction, deposition film greater detail and smooth; in chemical bath in mixed ethanol solvent found mixed with 10% ethanol deposited films over the flat, reducing homogeneous nucleation reaction, when mixed 20% ethanol solvent, the film generated holes, and homogeneous nucleation reaction upgrade , produce more Cd(OH)2; (2) CZTS absorbing layer through experimental analysis, the Sulfurization temperature of 350oC to 500oC, 450oC CZTS film produced at an average grain size smaller than the film formation, and can nip best energy gap 1.5eV; (3) using CZTS thin films with different sol-gel reaction of the solvent, methanol, ethanol and ethylene glycol compared to the average grain smaller than the film formation, the optical absorption coefficient of 104cm-1 also on (2.7x104cm-1); (4) with ethanol as the solvent for preparing CZTS absorbing layer, a buffer layer of cadmium/sulfur ratio of 1/10, the deposition time was 10min, the vulcanization temperature 350oC to 500oC in the battery element will have different conversion efficiency. ηe generated by the Sulfurization temperature of 350oC efficiency unable to cure a slight increase in the temperature of 450oC, FF along with the Sulfurization temperature rises; under different sol-gel solvent, ethanol had a better efficiency.

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48

Hui-JuChen and 陳惠茹. "Study of Cu2ZnSnS4 thin films for photovoltaic applications." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/34657477103878149965.

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49

Chen, Huiling, and 陳慧玲. "Preparation of Cu2ZnSnS4 Thin Filmsby Wet Chemical Method." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/34389867567130376407.

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Abstract:

碩士
亞洲大學
光電與通訊學系碩士班
100
Cu2ZnSnS4 (CZTS) films were synthesized by wet chemical processes and then annealed under controlled argon atmosphere. This study was conducted in two stages. In the first stage, the precursor solutions were prepared in three levels of sulfur content. These films were deposited from the precursor solutions and annealed at 250 ℃ for 1 hour. The results showed that the CZTS film deposited from the sulfur content S3.0 had the better optoelectronic properties as compared to its counterparts. The optical energy gap value was 1.52 eV, and the absorption coefficient was greater than 104 cm-1, while it had the smallest resistivity of 4.68 Ω cm. In the second stage, the annealing temperature was set at 300 and 350 ℃ to identify how it would affect these film’s structures and optoelectronic properties. The film annealed at 250 ℃ was introduced for the purpose of comparison. It was found that when the annealing temperature increased from 250 to 350 ℃, all the films were of the Kesterite structure, and no secondary phase was observed. As demonstrated, the thermal compressive stress generated as the annealing temperature increased could change the appearances of the films. More particularly, the crackled surface was changed to one with hillocks. The films optical direct energy gap values were increased from 1.52 to 1.68 eV and the resistivities were increased from 4.68 to 124.49 Ω cm. Each of the CZTS films had absorption coefficients greater than 104 cm-1.

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50

Ansari, Mohd Zubair. "Cu2ZnSnS4 nanoparticles and thin films : characterizations and applications." Thesis, 2017. http://localhost:8080/iit/handle/2074/7508.

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