Dissertations / Theses on the topic 'Organic-inorganic perovskites'
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Niu, Wendy Wanru. "Excitons in 2D organic-inorganic lead iodide perovskites." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708847.
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Heller, Kyle Jeffrey. "CRYSTALLOGRAPHY OF TITANIUM BASED ORGANIC-INORGANIC HALIDE PEROVSKITES." OpenSIUC, 2020. https://opensiuc.lib.siu.edu/theses/2798.
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Kyle Heller, for the Master of Science degree in Mechanical Engineering, presented on October 2020, at Southern Illinois University Carbondale.MAJOR PROFESSOR: Dr. Kanchan Mondal Using powder X-ray diffraction, a material can have its crystalline structure identified. Powder X-ray diffraction alone is not enough if a material is unknown. Usually the exact chemical formula of the material is known, or a secondary analytical method is used to extract additional data in order to analyze the crystalline structure using Bragg’s law and the interplanar relationships. Secondary analytical methods are not as easy or inexpensive though. Generic values could be placed into the more basic structure types to obtain a rough idea of potential crystal types including space groups for the material based on its diffraction peaks. However, with a material that has an unknown spacing between its atoms (d-spacing) this is harder to implement. Thus, the use of a secondary software was employed to further analyze the possibilities. In this thesis, the software used for data extraction and refining were Expo 2014 and CrystalMaker X paired with CrystalDiffract and the final visualization was achieved using Endeavor. Two different titanium based organic inorganic halide perovskites (Dye 3 and Dye 4) prepared at different temperatures were evaluated to identify the crystallographic structure using only x-ray data available. The crystal parameters were calculated, and potential unit cells were visualized. Both the materials were found to be 4 (ABX3) type perovskites. The organic component for Dye 3 was methyl ammonium ion and that of Dye 4 was formamidinium ion. These perovskites have shown potential for use as sensitizers in visible light photovoltaic cells. It was concluded that Dye 4 was orthorhombic with a space grouping of C m c a (space group 64). The associated values were a = b =7.94 Å and c =11.55 Å. Dye 3 was also found to be orthorhombic with space grouping of P c c n (space group 56) being a better fit than C m c a. The associated values were a=b=16 Å and c=11 Å.
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Lee, Michael M. "Organic-inorganic hybrid photovoltaics based on organometal halide perovskites." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:9384fc54-30de-4f0d-86fc-71c22d350102.
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This thesis details the development of a novel photovoltaic device based on organometal halide perovskites. The initial focus of this thesis begins with the study of lighttrapping strategies in solid-state dye-sensitised solar cells (detailed in chapter 3). While I report enhancement in device performance through the application of near and far-field light-trapping techniques, I find that improvements remain step-wise due to fundamental limitations currently employed in dye-sensitised solar cell technology— notably, the available light-sensitising materials. I found a promising yet under researched family of materials in the methyl ammonium tri-halide plumbate perovskite (detailed in chapter 4). The perovskite light-sensitiser was applied to the traditional mesoscopic sensitised solar cell device architecture as a replacement to conventional dye yielding world-record breaking photo-conversion e!ciencies for solid-state sensitised solar cells as high as 8.5%. The system was further developed leading to the conception of a novel device architecture, termed the mesoporous superstructured solar cell (MSSC), this new architecture replaces the conventional mesoporous titanium dioxide semiconductor with a porous insulating oxide in aluminium oxide, resulting in very low fundamental losses evidenced through high photo-generated open-circuit voltages of over 1.1 V. This development has delivered striking photo-conversion ef- ficiencies of 10.9% (detailed in chapter 6).
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Azarhoosh, Pooya. "The optical and electronic properties of organic-inorganic hybrid perovskites." Thesis, King's College London (University of London), 2018. https://kclpure.kcl.ac.uk/portal/en/theses/the-optical-and-electronic-properties-of-organicinorganic-hybrid-perovskites(7ee3095e-05fa-49b9-9404-d481147c67b4).html.
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The primary focus of this thesis is the study of a novel family of materials known as organicinorganic hybrid Perovskites (OIHP), which have recently demonstrated to possess remarkable photovoltaic efficiency. The fundamental properties of these materials related to photovoltaic (PV) applications are studied to characterise electronic and optical behaviours. An all-electron implementation of the Quasi-particle Self-consistent GW (QSGW) is used to perform first principles calculations. The quasi-particle energy bands are analysed for a number of Perovskites, to identify trends and characteristics within this family of materials, and to understand the dielectric response. The dielectric function and refractive index were studied for 4 OIHP and compared to experimental work carried out collaboratively with Leguy et al. [1]. It is found that the relativistic effects are extremely important in characterisation of these materials. The presence of strong spin-orbit interaction combined with significant internal electric fields yields anomalously large Rashba splitting of both valence and conduction states near the band edges. This significantly perturbs the electronic and optical properties of these materials. Such effects have not been previously investigated in the context of photovoltaic materials. The effect of the Rashba splitting on the radiative recombination lifetime of charge carriers is investigated. A model for reciprocal space trapping mechanism of carriers was developed and implemented within the Questaal package. The slightly indirect gap induced by Rashba splitting results in a strongly suppressed photoluminescence when compared to conventional III-V direct-gap semiconductors with an otherwise approximately similar band structure. Such suppression of the radiative recombination enhances the diffusion length and can significantly increase the power conversion efficiency of a solar cell.
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Zu, Fengshuo. "Electronic properties of organic-inorganic halide perovskites and their interfaces." Doctoral thesis, Humboldt-Universität zu Berlin, 2019. http://dx.doi.org/10.18452/20396.
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Über die besonders hohe Effizienz von Halid-Perowskit (HaP)-basierten optoelektronischen Bauteilen wurde bereits in der Literatur berichtet. Um die Entwicklung dieser Bauteile voranzutreiben, ist ein umfassendes und verlässliches Verständnis derer elektronischen Struktur, sowie der Energielevelanordnung (ELA) an HaP Grenzflächen von größter Bedeutung. Demzufolge beschäftigt sich die vorliegende Arbeit mit der Untersuchung i) der Bandstruktur von Perowskit-Einkristallen, um ein solides Fundament für die Darlegung der elektronischen Eigenschaften von polykristallinen Dünnschichten zu erarbeiten, und mit ii) den Einflüssen von Oberflächenzuständen auf die elektronische Struktur der Oberfläche, sowie deren Rolle bei der Kontrolle von ELA an HaP Grenzflächen. Die Charakterisierung erfolgt überwiegend mithilfe von Photoelektronenspektroskopie (PES) und ergänzenden Messmethoden wie Beugung niederenergetischer Elektronen an Oberflächen, UV-VIS-Spektroskopie, Rasterkraftmikroskopie und Kelvin-Sonde.
Erstens weist die Banddispersion von zwei prototypischen Perowskit-Einkristallen eine starke Dispersion des jeweiligen oberen Valenzbandes (VB) auf, dessen globales Maximum in beiden Fällen am R-Punkt in der Brillouin-Zone liegt. Dabei wird eine effektive Lochmasse von 0.25 m0 für CH3NH3PbBr3, bzw. von ~0.50 m0 für CH3NH3PbI3 bestimmt. Basierend auf diesen Ergebnissen werden die elektronischen Spektren von polykristallinen Dünnschichten konstruiert und es wird dadurch aufgezeigt, dass eine Bestimmung der Valenzbandkantenposition ausgehend von einer logarithmischen Intensitätsskala aufgrund von geringer Zustandsdichte am VB Maximum vorzuziehen ist.
Zweitens stellt sich bei der Untersuchung der elektronischen Struktur von frisch präparierten Perowskit-Oberflächen heraus, dass die n-Typ Eigenschaft eine Folge der Bandverbiegung ist, welche durch donatorartige Oberflächenzustände hervorgerufen wird. Des Weiteren weisen die PES-Messungen an Perowskiten mit unterschiedlichen Zusammensetzungen aufgrund von Oberflächenphotospannung eine Anregungslichtintensitätsabhängigkeit der Energieniveaus von bis zu 0.7 eV auf. Darüber hinaus wird die Kontrolle von ELA durch gezielte Variation der Oberflächenzustandsdichte gezeigt, wodurch sich unterschiedliche ELA-Lagen (mit Abweichungen von über 0.5 eV) an den Grenzflächen mit organischen Akzeptormolekülen erklären lassen. Die vorliegenden Ergebnisse verhelfen dazu, die starke Abweichung der in der Literatur berichteten Energieniveaus zu erklären und somit ein verfeinertes Verständnis des Funktionsprinzips von perowskit-basierten Bauteilen zu erlangen.Optoelectronic devices based on halide perovskites (HaPs) and possessing remarkably high performance have been reported. To push the development of such devices even further, a comprehensive and reliable understanding of their electronic structure, including the energy level alignment (ELA) at HaPs interfaces, is essential but presently not available. In an attempt to get a deep insight into the electronic properties of HaPs and the related interfaces, the work presented in this thesis investigates i) the fundamental band structure of perovskite single crystals, in order to establish solid foundations for a better understanding the electronic properties of polycrystalline thin films and ii) the effects of surface states on the surface electronic structure and their role in controlling the ELA at HaPs interfaces. The characterization is mostly performed using photoelectron spectroscopy, together with complementary techniques including low-energy electron diffraction, UV-vis absorption spectroscopy, atomic force microscopy and Kelvin probe measurements. Firstly, the band structure of two prototypical perovskite single crystals is unraveled, featuring widely dispersing top valence bands (VB) with the global valence band maximum at R point of the Brillouin zone. The hole effective masses there are determined to be ~0.25 m0 for CH3NH3PbBr3 and ~0.50 m0 for CH3NH3PbI3. Based on these results, the energy distribution curves of polycrystalline thin films are constructed, revealing the fact that using a logarithmic intensity scale to determine the VB onset is preferable due to the low density of states at the VB maximum. Secondly, investigations on the surface electronic structure of pristine perovskite surfaces conclude that the n-type behavior is a result of surface band bending due to the presence of donor-type surface states. Furthermore, due to surface photovoltage effect, photoemission measurements on different perovskite compositions exhibit excitation-intensity dependent energy levels with a shift of up to 0.7 eV. Eventually, control over the ELA by manipulating the density of surface states is demonstrated, from which very different ELA situations (variation over 0.5 eV) at interfaces with organic electron acceptor molecules are rationalized. Our findings further help to explain the rather dissimilar reported energy levels at perovskite surfaces and interfaces, refining our understanding of the operational principles in perovskite related devices.
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Kovalsky, Anton. "PHOTOVOLTAIC AND THERMAL PROPERTIES OF HYBRID ORGANIC-INORGANIC METAL HALIDE PEROVSKITES." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1500584556606705.
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Akbarian-Tefaghi, Sara. "Microwave-Assisted Topochemical Manipulation of Layered Oxide Perovskites: From Inorganic Layered Oxides to Inorganic-Organic Hybrid Perovskites and Functionalized Metal-Oxide Nanosheets." ScholarWorks@UNO, 2017. http://scholarworks.uno.edu/td/2287.
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Developing new materials with desired properties is a vital component of emerging technologies. Functional hybrid compounds make an important class of advanced materials that let us synergistically utilize the key features of the organic and inorganic counterparts in a single composite, providing a very strong tool to develop new materials with ”engineered” properties. The research presented here, summarizes efforts in the development of facile and efficient methods for the fabrication of three- and two-dimensional inorganic-organic hybrids based on layered oxide perovskites. Microwave radiation was exploited to rapidly fabricate and modify new and known materials. Despite the extensive utilization of microwaves in organic syntheses as well as the fabrication of the inorganic solids, the work herein was among the first reported that used microwaves in topochemical modification of the layered oxide perovskites. Our group specifically was the first to perform rapid microwave-assisted reactions in all of the modification steps including proton exchange, grafting, intercalation, and exfoliation, which decreased the duration of multi-step modification procedures from weeks to only a few hours. Microwave-assisted grafting and intercalation reactions with n-alkyl alcohols and n-alkylamines, respectively, were successfully applied on double-layered Dion-Jacobson and Ruddlesden-Popper phases (HLaNb2O7, HPrNb2O7, and H2CaTa2O7), and with somewhat more limited reactivity, applied to triple-layered perovskites (HCa2Nb3O10 and H2La2Ti3O10). Performing neutron diffraction on n-propoxy-LaNb2O7, structure refinement of a layered hybrid oxide perovskite was then tried for the first time. Furthermore, two-dimensional hybrid oxides were efficiently prepared from HLnNb2O7 (Ln = La, Pr), HCa2Nb3O10, HCa2Nb2FeO9, and HLaCaNb2MnO10, employing facile microwave-assisted exfoliation and post-exfoliation surface-modification reactions for the first time. A variety of surface groups, saturated or unsaturated linear and cyclic organics, were successfully anchored onto these oxide nanosheets. Properties of various functionalized metal-oxide nanosheets, as well as the polymerization of some monomer-grafted nanosheets, were then investigated for the two-dimensional hybrid systems.
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Sun, Shijing. "Synthesis, characterization and properties of hybrid organic-inorganic perovskites for photovaltaic applications." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/267739.
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The hybrid organic-inorganic perovskites (HOIPs), e.g. methylammonium and formamidinium lead halide (MA/FAPbX3, X = I, Br or Cl), are a class of materials that has recently achieved remarkable performances in photovoltaic applications. This thesis describes the synthesis, structure and properties of this class of perovskites, with particular focus on their crystal chemistry, mechanical responses and structural diversity. Understanding the unique crystal chemistry of HOIPs is crucial for device design. While MA-based perovskites have been widely studied, there are still many open questions on the crystal chemistry of FA-based perovskites. In this work, FAPbX3 (X= Br or I) was shown to undergo a cubic (Pm3 ̅m) to tetragonal (P4/mbm) transition on cooling. Studies on the high-pressure crystallography of FAPbI3 exhibited a similar trend and further illustrated band gap tuning via external stimuli. In addition, the cubic lattice of FAPbBr3 was found to be more strained than its MA counterpart. The observed intrinsic strain was modelled with anisotropic line broadening and < 100 > was found to be the least strained direction. To explore potential applications in flexible devices, crystals of single (Pb-based) and double (Bi-based) perovskites were probed by nanoindentation and their mechanical properties, such as Young’s moduli (E) (10 – 20 GPa) and hardnesses (H) (0.2 -0.5 GPa), were determined. The mechanical responses of MA- and FA-based hybrid perovskites correlated well with the chemical and structural variations in these analogues, showing a general trend of ECl > EBr > EI and EPb > EBi. By analogy with classical inorganic perovskites, the hybrid phases can crystallise in both three-dimensional (3D) and low dimensional perovskite-like forms. To improve the stability and remove the toxicity in the current prototypical hybrid perovskites, compositional engineering was applied, focusing on non-toxic bismuth (Bi) as a viable alternative to lead (Pb) in future photovoltaic materials. We report a new layered perovskite, (NH4)3Bi2I9, which exhibits a band gap of 2.0 eV, comparable to MAPbBr3 and FAPbBr3. This work contributes to the materials design goal of more stable and eco-friendly perovskite devices.
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Vega, Fleitas Erica. "Study and Characterization of Hybrid Organic-Inorganic Perovskites for Solar Cells Applications." Doctoral thesis, Universitat Politècnica de València, 2018. http://hdl.handle.net/10251/113402.
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[ES] Las perovskitas orgánicas-inorgánicas de haluros de metilamonio y plomo y sus mezclas han mostrado propiedades optoelectrónicas óptimas como absorbente ideal para aplicaciones fotovoltaicas. Los dispositivos solares basados en perovskita han evolucionado rápidamente, desde una eficiencia del 3.9% en 2009, al 22.7% en 2017 y con un coste de fabricación más bajo que las células solares de silicio. Una desventaja del uso de absorbentes de perovskita en dispositivos fotovoltaicos es su baja estabilidad. Las células con un alto rendimiento, pierden su eficiencia y se degradan rápidamente. Para poder producir estos materiales industrialmente es necesario realizar estudios en profundidad que mejoren la eficiencia y estabilidad. Una vía de mejora es la ingeniería composicional, estrategia que hemos empleado en la elaboración de esta tesis y que consiste en la investigación y mejora de las propiedades optoelectrónicas y morfológicas, derivadas de la sustitución y/o combinación de cationes y aniones, que constituyen el material de perovskita. Se sintetizaron polvos puros de perovskita de I, Br, Cl, a partir de los cuales se prepararon capas puras y mixtas MAPbX3-xYx, con el objetivo de mejorar sus propiedades optoelectrónicas y estructurales. Los análisis de difracción de rayos X mostraron las propiedades estructurales de los polvos cristalinos y capas puras y mixtas. Los análisis de UV-vis y fotoluminiscencia mostraron que el rango de absorción varía a lo largo del espectro visible en función del contenido del haluro en las capas. Los análisis de fotoluminiscencia y calorimetría diferencial de barrido muestran los cambios de fase de las perovskitas puras a distintas temperaturas, coincidiendo dichos cambios en ambos análisis. El análisis FESEM de las perovskitas puras mostró las diferencias morfológicas entre los polvos y capas. Siguiendo esta línea de investigación, se estudiaron con más detalle las perovskitas mixtas de yodo-bromo, con un contenido de bromo de hasta el 33%, consiguiendo ajustar el bandgap para evitar pérdidas en la absorción y mejorar las propiedades optoelectrónicas, estructurales y morfológicas. A pesar de las buenas propiedades optoelectrónicas de las perovskitas de metilamonio, el catión orgánico disminuye su estabilidad, lo que llevó a investigar otros cationes inorgánicos. Las perovskitas de cesio son una alternativa prometedora, y por esta razón hemos sintetizado capas finas de perovskitas de cesio mixtas, CsPbBr3-xIx, para determinar los efectos que produce la sustitución parcial del yodo en las propiedades físicas y la estabilidad. Se obtuvieron capas con una buena resistencia a la humedad y temperatura, favoreciendo su aplicación en el campo fotovoltaico. Se ha estudiado la sustitución parcial del catión de metilamonio con otros cationes orgánicos, como el guanidinio e imidiazolio. Se demostró que pequeñas cantidades de guanidinio mejoran la estabilidad de las capas y su morfología. Se estableció el límite de solubilidad del guanidinio en el 20%, aproximadamente, y se determinó la estructura cristalina de las mezclas. La intensidad del pico de fotoluminiscencia aumentó para mezclas por debajo del límite de solubilidad. Se obtuvieron resultados similares para la sustitución del metilamonio con pequeñas cantidades de imidazolio. Los análisis de rayos X establecieron el límite de solubilidad en aproximadamente el 10% y una mejora en la cristalinidad. Los resultados de fotoluminiscencia sugieren que pequeñas cantidades de imidazolio reducen significativamente las recombinaciones no radiativas, actuando como un pasivador efectivo. Finalmente, se muestra el proceso de fabricación de dispositivos basados en MAPbI3 y sintetizados en función de las condiciones ambientales y empleando el dietil éter como anti-solvente. Los dispositivos mostraron una eficiencia máxima del 14.73%. Se ha probado que la oxidación del spiro-OMeTAD, bajo condiciones cont[FR] Les perovskites orgàniques-inorgàniques de halurs de metilamoni i plom i les seues mescles han mostrat propietats optoelectròniques òptimes com a absorbent ideal per a aplicacions fotovoltaiques. Els dispositius solars basats en perovskita han evolucionat ràpidament, passant d'una eficiència del 3.9% en 2009, fins al 22.7% en 2017, i amb un cost de fabricació més baix que les cèl·lules solars de silici. No obstant això, un dels desavantatges de l'ús de absorbents de perovskita és la baixa estabilitat. En general, les cèl·lules que mostren un alt rendiment, perden la seua eficiència i es degraden ràpidament. Per a que aquestos materials puguen ser produits industrialment a gran escala és necessari estudiar-los en profunditat per millorar la eficiència i estabilitat. Una de les vies de millora és l'enginyeria composicional, estratègia que hem emprat en l'elaboració d'aquesta tesi i que consisteix en la investigació i la millora de les propietats optoelectròniques i morfològiques, derivades de la substitució i/o combinació de cations i anions, que constitueixen el material de perovskita. S'han sintetitzat pols purs de perovskita per a I, Br, Cl, a partir d'els quals es van preparar capes pures i mixtes MAPbX3-xYx per a millorar les propietats optoelectròniques i estructurals. Mitjançant anàlisi de difracció de raigs X, s'estudiaren les propietats estructurals del pols cristalins i capes pures i mixtes. Els anàlisis d'UV-vis i fotoluminiscència, mostren que el rang d'absorció varia al llarg de l'espectre visible en funció del contingut de l'halur. Les anàlisis de fotoluminiscència i calorimetria diferencial mostren els canvis de fase de les perovskites pures a diferents temperatures, coincidint aquestos canvis en totes dues anàlisis. L'anàlisi FESEM de les perovskites pures, mostra les diferències morfològiques entre els pols i capes. Seguint aquesta línia d'investigació, s'estudiaren les perovskites mixtes de iode-brom, amb un contingut de brom de fins el 33%, ajustant el bandgap per a evitar pèrdues en l'absorció i millorar les propietats optoelectròniques, estructurals i morfològiques. Malgrat les bones propietats optoelectròniques de les perovskites de metilamoni, el catió orgànic disminueix la estabilitat, la qual cosa ha portat a investigar l'ús d'altres cations inorgànics. Les perovskites de cesi són una alternativa prometedora, i per aquesta raó hem sintetitzat capes fines de perovskites de cesi mixtes, CsPbBr3-xIx, per tal de determinar els efectes de la substitució parcial del iode en les propietats físiques i l'estabilitat. Es van obtenir capes amb una bona resistència a la humitat i a la temperatura, afavorint la seua aplicació en el camp fotovoltaic. S'ha estudiat també la substitució parcial del catió de metilamoni amb altres cations orgànics, com el guanidini i imidiazoli. S'ha demostrat que petites quantitats de guanidini milloren l'estabilitat i la morfologia de les capes. S'ha establert que el límit de solubilitat del guanidini es del 20%, aproximadament, i s'ha determinat l'estructura cristal·lina de les mescles. S'ha observat un augment en la intensitat del pic de fotoluminiscència per a mescles per sota del límit de solubilitat. Es van obtenir resultats similars per a la substitució del metilamoni amb petites quantitats de imidazoli. Les anàlisis de difracció de raigs X van establir el límit de solubilitat en aproximadament el 10% i una millora en la cristalinitat. Els resultats de fotoluminiscència suggereixen que petites quantitats de imidazoli redueixen les recombinacions no radiatives, actuant com un pasivador efectiu. Finalment, es mostra el procés de fabricació de dispositius basats en MAPbI3 i sintetitzats en funció de les condicions ambientals, especialment la humitat relativa i utilitzant el dietil èter com anti-solvent. Els dispositius van mostrar una eficiència màx
[EN] Organic-inorganic methylammonium lead halides perovskites and their mixtures have shown optimal optoelectronic properties as an ideal absorber for photovoltaic applications. In the last decade, solar devices based on perovskite have evolved rapidly, going from an initial efficiency of only 3.9% in 2009, to an efficiency of 22.7% in 2017 and being, at the same time, more cost-effective than silicon solar cells. However, one of the main disadvantages when using perovskite absorbents in photovoltaic devices is their low stability. In general, cells that show high performance lose their efficiency and degrade rapidly. For these materials to be scalable it is necessary to carry out in-depth studies aiming at improved efficiency and stability. One of the main sources to improve stability and efficiency is compositional engineering, a strategy employed in the elaboration of this thesis, consisting of the investigation and improvement of the optoelectronic and morphological properties, derived from the substitution and / or combination of cations and anions, which constitute the perovskite material. Pure powders of perovskite were synthesized, for I, Br, Cl, from which pure and mixed MAPbX3-xYx films were prepared in order to improve their optoelectronic and structural properties. By means of X-ray diffraction analysis, the structural properties of crystalline powders and pure and mixed films were studied. Employing UV-vis and photoluminescence analysis, it was observed that the absorption range varied along the visible spectrum as a function of the halide content in the thin films. Both, photoluminescence and differential scanning calorimetry analysis showed the changes of phase of the pure perovskites at different temperatures. FESEM characterization of the pure perovskites showed the morphological differences between the powders and the films. Following this line of research, mixed perovskites of iodine-bromine with a bromine content of up to 33% were studied in more detail. The bandgap was tuned to avoid significant losses in absorption and improve the optoelectronic, structural and morphological properties. Despite the excellent optoelectronic properties of the methylammonium perovskite, the presence of the organic cation decreases its stability, which prompted research into the use of other inorganic cations. Cesium perovskites, are a very promising alternative, and for this reason we synthesized thin films of mixed cesium perovskites, CsPbBr3-xIx, to determine the effects of the partial substitution of iodine on physical properties and stability. Films with a very good resistance to moisture and temperature were obtained, which will favor the application of this type of perovskites in the photovoltaic field. The partial replacement of the methylammonium cation with other organic cations, such as guanidinium and imidiazolium, was also studied, showing that small amounts of guanidinium significantly improve the stability of the films and their morphology. It was established that the solubility limit of guanidinium is approximately 20%, and the crystalline structure of the mixtures was determined. An increase in the intensity of the photoluminescence peak for mixtures below the solubility limit was observed. Similar results were obtained for the substitution of methylammonium with small amounts of imidazolium. X-ray diffraction analyzes established the solubility limit at approximately 10% and an improvement in crystallinity. Photoluminescence results suggest that small amounts of imidazolium significantly reduce nonradiative recombinations, acting as an effective passivator. Finally, the manufacturing process of devices based on MAPbI3 and synthesized according to environmental conditions, especially relative humidity and using diethyl ether as anti-solvent is shown. The devices presented a maximum efficiency of 14.73%, proving that the oxidation of spiro-OMeTAD, under controlled humidity conditions, can improve efficiency.
Vega Fleitas, E. (2018). Study and Characterization of Hybrid Organic-Inorganic Perovskites for Solar Cells Applications [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/113402
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Ghanavi, Saman. "Organic-inorganic hybrid perovskites as light absorbing/hole conducting material in solar cells." Thesis, Uppsala universitet, Fysikalisk kemi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-205605.
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Solar cells involving two different perovskites were manufactured and analyzed. The perovskites were (CH3NH3)PbI3 and (CH3NH3)SnI3. Both perovskites have a shared methyl ammonium group (MA) and are used as both light absorbing material and hole conducting material (HTM) in this project. The preparation procedures for the complete device were according to previous attempts to make stable organic-inorganic hybrid perovskites and involved different layers and procedures. Both perovskites were manufactured by mixing methyl ammonium iodide with either lead iodide or tin iodide in different concentrations. This was then deposited on a 600nm thick mesoporous TiO2 layer. Deposition of the hole-transporting material (HTM) was done by spin-coating 2,2´,7,7´-tetrakis-(N,N-dip-methoxyphenylamine) 9,9´-spirobifluorene, also called spiro-OMeTAD. Lastly thermal evaporation was used to deposit a silver electrode. Different measurements were done on the light absorbing materials. The lead perovskite solar cell device was subjected to illumination with Air Mass 1.5 sunlight (100mW/cm2) which produced an open circuit voltage Voc of 0.645 V, a short circuit photocurrent Jsc of about 7 mA/cm2, and a fill factor FF of 0.445. This resulted in a power conversion efficiency (PCE) of about 2% and an incident photon to current efficiency (IPCE) of up to 60%. The tin perovskite has not been used in solar cells before and the initial results presented here shows low performance using the same device construction as for the lead perovskite. However, the incident photon to electron conversion affirms that there is a current in the visible region, and IPCE of 12.5 % was observed at 375nm. UV-visible NIR measurement was used to analyze the light absorption of the perovskite structures and a broader light absorption was observed for the lead perovskite compared to the tin perovskite. X-ray diffraction (XRD) analyzing was done on both perovskite materials using different concentrations and both with and without nanoporous TiO2 film. Both perovskites demonstrate very similar peaks with some exceptions. Photo-induced absorption (PIA) measurement was used for the purpose of showing the magnitude of charge separation or hole transfer in the light absorbing material, both when using the perovskites as a light absorber and a hole conductor. This is measured by analyzing the hole injection from the excited light absorber into the HTM. Hole transfer was observed for the lead perovskite (when used as light absorber) and tin perovskite (when used as hole conductor).
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Wei, Yi. "Synthesis and optical properties of self-assembled 2D layered organic-inorganic perovskites for optoelectronics." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2012. http://tel.archives-ouvertes.fr/tel-00905415.
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The innovation of advanced technology and the requirement of electronic market are always focusing on low cost electronics, presenting an easy processing and having enhanced performance. Organic-inorganic hybrid perovskites, which combine the properties of organic and inorganic semiconductors, are hopeful candidates for future opto-electronic devices. The exciton binding energies and oscillator strengths are very large in these systems making the applications at room temperature possible. In this thesis, we study the flexibility and photostability of self-assembled two-dimensional layered perovskites (R-NH3)2PbX4. By modifying the R structure, perovskites with optimized photoluminescence efficiency, surface roughness and photostability are discovered. We develop also some methodologies to fabricate crystal bulks and nanoparticles of perovskites, and we create new mixed perovskite crystals: (RNH3)2PbYxX4-x and AB-(NH3)2PbX4. Vertical microcavities containing these new materials and working in the strong coupling regime at room temperature have been realized, the emission of the lower energy polariton is observed.
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Lini, Matilde. "Optoelectronic characterization of hybrid organic-inorganic halide perovskites for solar cell and X-ray detector applications." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23213/.
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In the last 10 years, the research interest has been drawn towards the hybrid organic-inorganic halide perovskites, an innovative material characterized by remarkable optoelectronic properties and by its simplicity of fabrication; hybrid halide perovskites are currently being employed as active material in solar cells, X-ray photodetectors and light emitting devices.
The following thesis presents the characterization of two perovskite-based materials. The first is a methylammonium lead iodide (MAPbI3) thin film solar cell, which has been
fabricated and characterized at the University of Konstanz (Germany), with the aim to optimize the deposition procedure. The second material is a methylammonium lead bromide (MAPbBr3) single crystal that have been characterized at the University of
Bologna with surface photovoltage and photocurrent spectroscopies, as a function of the deposited dose of X-rays in order to monitor the induced effects of radiation.
After the exposure to X-rays, the exciton binding energy, calculated from the surface photovoltage spectra, has been found to increase by 20 meV with respect to the not irradiated sample. A similar result has been found with the photocurrent spectroscopy. The reasons for the increase in binding energy is discussed and attributed to a change in polarizability of the single crystal. The recovery of the crystals has been registered as well and has shown that the material is able to return to the initial condition after just few hours from the last X-ray's deposition.
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Watthage, Suneth C. "Solution-Processed Fabrication of Hybrid Organic-Inorganic Perovskites & Back Interface Engineering of Cadmium Telluride Solar Cells." University of Toledo / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1512390043951256.
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Zu, Fengshuo [Verfasser], Norbert [Gutachter] Koch, Christoph T. [Gutachter] Koch, and Derck [Gutachter] Schlettwein. "Electronic properties of organic-inorganic halide perovskites and their interfaces / Fengshuo Zu ; Gutachter: Norbert Koch, Christoph T. Koch, Derck Schlettwein." Berlin : Humboldt-Universität zu Berlin, 2019. http://d-nb.info/1193489768/34.
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Omondi, Celline Awino [Verfasser], Bernd [Gutachter] Rech, Roland [Gutachter] Scheer, and Thomas [Gutachter] Dittrich. "Investigation of hybrid organic-inorganic lead halide perovskites by modulated surface photovoltage spectroscopy / Celline Awino Omondi ; Gutachter: Bernd Rech, Roland Scheer, Thomas Dittrich." Berlin : Technische Universität Berlin, 2018. http://d-nb.info/1164498150/34.
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Aversa, Pierfrancesco. "Primary Defects in Halide Perovskites : Effect on Stability and Performance for Photovoltaic Applications Effect of organic PCBM Electron transport Layers on natural and post-irradiation ageing of optical absorption and emission in methyl ammonium lead triiodide spin –coated on p-i-n Solar Sell Substrates Effect of organic PCBM Electron transport Layers on natural and post-irradiation ageing of optical absorption and emission in triple cation lead mixed halide perovskite spin –coated on p-i-n Solar Sell Substrates Electron Irradiation Induced Ageing Effects on Radiative Recombination Properties of methylammonium lead triiodide layers on p-i-n solar cell substrates Electron Irradiation Induced Ageing Effects on Methylammonium Lead Triiodide Based p-i-n Solar Cells Electron Irradiation Induced Ageing Effects on Radiative Recombination Properties of Quadruple Cation Organic-Inorganic Perovskite Layers." Thesis, Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAX050.
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Ces onze dernières années ont vu apparaitre les pérovskites organiques inorganiques hybrides (HOIPs) comme un passionnant domaine de recherche pour leur application potentielle dans les technologies du photovoltaïque (PV) en raison de leurs exceptionnelles propriétés optoélectroniques et de leur facilité de mise en oeuvre. Cependant, les matériaux HOIPs ont plusieurs inconvénients dont leur manque de stabilité en conditions opérationnelles. Améliorer celle-ci est l'un des plus grands défis à relever avant commercialisation. La formule générale est (A1,A2,A3,A4)Pb(X1,X2)3, où les sites A occupés par une distribution de 1 à 4 cations métalliques/organiques et les sites X par celle d’anions halogénures. Les défauts lacunaires natifs sont considérés comme une cause possible de dégradation des cellules solaires HOIPs. L'objectif de ce travail est de comprendre le rôle des défauts dans la stabilité à long terme des matériaux PV HOIPs. A cette fin, des défauts primaires ont été introduits de manière contrôlée par irradiation avec des électrons de haute énergie (1MeV) dans des lots de couches et cellules solaires (SCs) à base de divers composés HOIPs. Il s'agit notamment du prototype PV HOIPs, MAPbI3 (A1PbX13), et de nouveaux composés mixtes d’halogénures à triple ou quadruple cations, (CsMAFA)Pb(I1-xBrx)3 (A3PbX23) ou (GACsMAFA)Pb(I1-yBry)3 (A4PbX23). Les couches sont fabriquées selon la même procédure que les couches actives SCs et, ensuite, traitées dans des conditions similaires. Pour A1PbX13/A3PbX23, la structure SC est de type p-i-n avec des couches organiques pour le transport des trous et des électrons (HTL/ETL). Les couches sont déposées sur le substrat verre/ITO/HTL (PEDOT:PSS) sans ou avec couche supérieure ETL (PCBM). Pour A4PbX23, la structure SC est de type n-i-p avec des couches ETL inorganiques (TiO2) et HTL organiques (Spiro-OMeTAD). Les couches sont directement déposées sur du verre.La spectroscopie d'annihilation de positons donne une évidence directe de l'existence de défauts lacunaires natifs et induits par irradiation dans chaque composé. Les spectres d’absorbance en fonction de l’énergie montrent que le vieillissement naturel et après irradiation génère différentes populations de défauts dans chaque composé. De plus, celles-ci pour A1PbX13 et A3PbX23 diffèrent selon l'absence ou la présence de la couche supérieure ETL. Les populations de défauts évoluent pendant au moins 3 mois. Le vieillissement modifie (i) la bande interdite, (ii) les queues de bande de conduction/valence et (iii) l'absorption optique via des niveaux électroniques profonds. Les effets d’illumination sous laser varient aussi en fonction du vieillissement. L’asymétrie des pics de photoluminescence (PL) dans chaque composé sous illumination laser continue reflète une superposition de raies d’émission gaussiennes à énergie, FWHM et hauteur évoluant avec le temps d'illumination. Les transitions d'émission impliquent des niveaux électroniques localisés peu profonds dans A3PbX23/A4PbX23 et résonnants dans A1PbX13. De tels effets durent au moins 3 mois dans A4PbX23. Ces niveaux électroniques sont attribués à des populations de défauts spécifiquement induits par illumination. Le vieillissement naturel et après irradiation donne des spectres PL à décroissance temporelle résolue en une ou deux exponentielles. Le nombre et la durée de vie sont fortement influencés par l’irradiation initiale et la composition. Une amélioration frappante du fonctionnement PV pour le type SC p-i-n est induite par le vieillissement dû à l'irradiation. Le rendement quantique externe et les performances PVs ont des valeurs plus élevées pour l’état irradié que de référence durant 6 à 12 mois de vieillissement. Cela prouve que l'ingénierie des défauts par irradiation d'électrons à haute énergie a le potentiel de fournir des voies de traitement innovantes pour améliorer la stabilité à long terme des performances photovoltaïques HOIPsDuring the last eleven years, Hybrid Organic Inorganic Perovskites (HOIPs) materials have emerged as an exciting topic of research for potential application in solar cell technologies due to their outstanding optoelectronic properties and processing advantages. However, HOIPs materials suffer from several drawbacks with, in peculiar, their lack of stability under operational conditions (light, bias, environment…). To improve this stability is one of the biggest challenges to be addressed before commercialization. The general formula for HOIPs is (A1,A2,A3,A4)Pb(X1,X2)3, where the A sites can be occupied by a distribution of 1 to 4 metallic/organic cations and X sites with halide anions. The role of native vacancy defects has been questioned as a possible cause for HOIPs solar cells degradation. The aim of this work is to understand the defect role in long term stability of HOIPs materials for photovoltaics. For this reason, primary defects were introduced in a controlled way via high energy electron irradiation (1MeV) in sets of layers and solar cells (SCs) fabricated using various HOIPs compounds. Those include the photovoltaic HOIPs prototype, MAPbI3 (A1PbX13), and emergent triple or quadruple cation mixed halide HOIPs, (CsMAFA)Pb(I1-xBrx)3 (A3PbX23) or (GACsMAFA)Pb(I1-yBry)3 (A4PbX23). The HOIPs layers are fabricated according to the same procedure as the HOIPs active SC layers and, subsequently, treated in similar conditions. For A1PbX13 and A3PbX23, the solar cells are of the p-i-n structure with organic hole and electron transport layer (HTL/ETL). The HOIPs layers are deposited on the glass/ITO/HTL (PEDOT:PSS) substrate without or with the top ETL layer (PCBM). For A4PbX23, the solar cells are of the n-i-p type with inorganic ETL (TiO2) and organic HTL (Spiro-OMeTAD) layers. The layers are directly deposited on glass without the ETL layer.Positron Annihilation Spectroscopy (PAS) gives direct evidence for native vacancy-type defects and irradiation induced ones in layers of each HOIP compound. The energy dependence of absorbance shows that natural and after irradiation ageing generates different defect populations in each HOIP compound. These populations strikingly also differ depending on the absence or presence of the top ETL layer for the A1PbX13 and A3PbX23 compounds. The defect populations evolve over ageing duration as long as 3 months. The prominent effects of ageing include (i) band gap modification, (ii) tailing of conduction/valence band extrema and (iii) optical absorption via deep subgap electronic levels. Illumination effects under laser also vary with ageing for each HOIP compound. Asymmetric photoluminescence (PL) peaks in each compound under continuous laser illumination reflect that radiative emission involves Gaussian emission rays with energy, FWHM and height evolving with illumination time. The emission transitions involve shallow localized electronic levels in A3PbX23 and A4PbX23 and resonant ones in A1PbX13. These electronic levels are attributed to specifically illumination-induced defect populations. Natural and after irradiation ageing result in PL decay lifetime spectra resolved into one or two exponential decay components. The decay components number and lifetime are strongly affected by the initial production of irradiation defects and HOIPs composition. Such effects last over 3 months at least in A4PbX23. The p-i-n solar cells exhibit most striking irradiation ageing induced photovoltaics performance. The External Quantum Efficiency (EQE versus photon energy) and the photovoltaic performance (I-V under illumination) of the irradiated solar cells have higher values than those in the reference SCs after 6 to 12 months of ageing. This gives evidence that defect engineering via high energy electron irradiation has a potential for providing innovative processing pathways to enhance the long-term stability of HOIPs photovoltaic performance
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Sarvari, Hojjatollah. "FABRICATION AND CHARACTERIZATION OF ORGANIC-INORGANIC HYBRID PEROVSKITE SOLAR CELLS." UKnowledge, 2018. https://uknowledge.uky.edu/ece_etds/123.
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Solar energy as the most abundant source of energy is clean, non-pollutant, and completely renewable, which provides energy security, independence, and reliability. Organic-inorganic hybrid perovskite solar cells (PSCs) revolutionized the photovoltaics field not only by showing high efficiency of above 22% in just a few years but also by providing cheap and facile fabrication methods.
In this dissertation, fabrication of PSCs in both ambient air conditions and environmentally controlled N2-filled glove-box are studied. Several characterization methods such as SEM, XRD, EDS, Profilometry, four-point probe measurement, EQE, and current-voltage measurements were employed to examine the quality of thin films and the performance of the PSCs. A few issues with the use of equipment for the fabrication of thin films are addressed, and the solutions are provided.
It is suggested to fabricate PSCs in ambient air conditions entirely, to reduce the production cost. So, in this part, the preparation of the solutions, the fabrication of thin films, and the storage of materials were performed in ambient air conditions regardless of their humidity sensitivity. Thus, for the first part, the fabrication of PSCs in ambient air conditions with relative humidity above ~36% with and without moisture sensitive material, i.e., Li-TFSI are provided. Perovskite materials including MAPbI3 and mixed cation MAyFA(1-y)PbIxBr(1-x) compositions are investigated. Many solution-process parameters such as the spin-coating speed for deposition of the hole transporting layer (HTL), preparation of the HTL solution, impact of air and light on the HTL conductivity, and the effect of repetitive measurement of PSCs are investigated. The results show that the higher spin speed of PbI2 is critical for high-quality PbI2 film formation. The author also found that exposure of samples to air and light are both crucial for fabrication of solar cells with larger current density and better fill factor. The aging characteristics of the PSCs in air and vacuum environments are also investigated. Each performance parameter of air-stored samples shows a drastic change compared with that of the vacuum-stored samples, and both moisture and oxygen in air are found to influence the PSCs performances. These results are essential towards the fabrication of low-cost, high-efficiency PSCs in ambient air conditions.
In the second part, the research is focused on the fabrication of high-efficiency PSCs using the glove-box. Both single-step and two-step spin-coating methods with perovskite precursors such as MAyFA(1-y)PbIxBr(1-x) and Cesium-doped mixed cation perovskite with a final formula of Cs0.07MA0.1581FA0.7719Pb1I2.49Br0.51 were considered. The effect of several materials and process parameters on the performance of PSCs are investigated. A new solution which consists of titanium dioxide (TiO2), hydrochloric acid (HCl), and anhydrous ethanol is introduced and optimized for fabrication of quick, pinhole-free, and efficient hole-blocking layer using the spin-coating method. Highly reproducible PSCs with an average power conversion efficiency (PCE) of 15.4% are fabricated using this solution by spin-coating method compared to the conventional solution utilizing both spin-coating with an average PCE of 10.6% and spray pyrolysis with an average PCE of 13.78%. Moreover, a thin layer of silver is introduced as an interlayer between the HTL and the back contact. Interestingly, it improved the current density and, finally the PCEs of devices by improving the adhesion of the back electrode onto the organic HTL and increasing the light reflection in the PSC. Finally, a highly reproducible fabrication procedure for cesium-doped PSCs using the anti-solvent method with an average PCE of 16.5%, and a maximum PCE of ~17.5% is provided.
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Pham, Ngoc Duy. "Efficiency enhancement in solution-processed organic-inorganic perovskite solar cells." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/133985/1/Ngoc%20Duy_Pham_Thesis.pdf.
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Organic-inorganic lead halide perovskite is a promising candidate in the photovoltaic field due to the combined merits of impressive power conversion efficiencies and relatively cost-effective solution processes. Despite its remarkable success, there is still room for further improvement. This thesis aims to investigate the impacts of morphological microstructure and elemental composition of organic-inorganic lead halide perovskite light absorber on power conversion efficiency, stability and current-voltage hysteresis behaviour of perovskite solar cells.
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Blomdahl, Emil. "Synthesis and characterization of novel hybrid organic-inorganic materials." Thesis, KTH, Tillämpad fysikalisk kemi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-302288.
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Efterfrågan på bättre och mer hållbart material ökar. Mer effektivt material kommer att behövas för att möta den ökande, globala efterfrågan. Hybrida organiska-oorganiska material är en typ av material som har varit av stort intresse nyligen, och kan beskrivas som en typ av material som består av både organiska och oorganiska komponenter. Denna avhandling har fokuserat på hybrida organiska-oorganiska material inspirerade av den klassiska perovskitstrukturen ABX3, där komponent A är en organisk katjon, komponent B är en divalent metalkatjon och komponent X är en anjon. Hybrida organiska-oorganiska material som är utgår från den klassiska perovskitstrukturen kan ha olika funktionella egenskaper och en bred variation av tänkbara applikationer. Några exempel på dessa egenskaper och möjliga applikationer inkluderar god fotokonduktivitet för solceller, utmärkt emissionsegenskaper för ljusdioder och justerbara dielektriska egenskaper för elektroniska växlar och sensorer. De fysiska egenskaperna av det hybrida organiska-oorganiska materialet beror på kristallstrukturen av materialet, som i sig bestäms av valet av komponenter. På grund av de många möjligheter av organiska och oorganiska komponenter så finns det möjlighet att syntetisera helt nya hybrida organiska-oorganiska föreningar som kan ha nya eller förbättrade fysiska egenskaper. Nuvarande hybrida organiska-oorganiska material som utgår från perovskitstrukturen använder huvudsakligen bly som divalent metalkatjon, och det beror på att den ger den bästa funktionella effekten. Blys toxicitet är dock en stor nackdel för nuvarande blybaserade hybrid oorganiska material. Möjligheten att ersätta bly med en annan divalent metall har undersökts under detta projekt. I denna avhandling så har den organiska katjonen cyclohexylammonium (CHA) varit i fokus som den organiska komponenten. Målet med detta examensarbete var att designa, syntetisera och karakterisera nytt hybrid organisk-oorganiskt material. De hybrida organiska-oorganiska föreningarna CHAZnBr3 och (CHA)2ZnBr4 syntetiserades för den första gången, så vitt författaren vet, och kommer vara i fokus i denna avhandling. De två nya hybrida organiska-oorganiska föreningarna blev strukturellt karakteriserade med X-ray Diffraction (XRD) och termiskt karakteriserade med Thermal Gravimetric Analysis (TGA) och Differential Scanning Calorimetry (DSC). Den första föreningen, CHAZnBr3, kunde bestämmas att vara ortorombisk vid 298 K. Föreningen bestämdes vara termisk stabil upp till 490 K, och genomgår en fasövergång vid 445 K. Den andra föreningen, (CHA)2ZnBr4, kunde inte bestämmas strukturellt vid varken 100 K eller 298 K. Föreningen bestämdes vara termisk stabil upp till 490 K, och genomgår en fasövergång vid 230 K. Ytterligare karakterisering krävs för att bättre förstå egenskaperna hos dessa föreningar och deras möjliga användningsområden.The demand for better and more sustainable material is increasing. More efficient materials will be needed to meet the growing global need. Hybrid organic-inorganic materials are one type of materials that have been of great interest recently, which can be described as a class of materials that mix organic and inorganic components. This thesis focused on hybrid organic-inorganic materials inspired by the classical perovskite crystal structure ABX3, where component A is an organic cation, component B is a divalent metal cation and component X is an anion. Hybrid organic-inorganic materials based on the classical perovskite structure may have various functional properties and may have a broad range of potential applications. Some examples of those properties as well as some and possible applications include good photoconductivity and power conversion efficiency for photovoltaic devices, excellent emission properties for light emitting diodes and tunable dielectric properties for electronic switches and sensors. The physical properties of the hybrid organic-inorganic material are determined by the crystal structure of the material, which in turn will be decided by the choice of components. With the many possible choices for organic and inorganic components, there is an opportunity to synthesize completely new hybrid organic-inorganic compounds that may display new or superior physical properties. Current hybrid organic-inorganic materials based on the perovskite crystal structure mainly use lead as the divalent metal, since it currently gives the best performance. The toxicity of lead is a major drawback for current lead-based hybrid organic-inorganic materials. The possibility to replace lead with another divalent metal has been explored during this project. For this thesis, the organic cation cyclohexylammonium (CHA) has been of focus as the organic component. The aim of this thesis was to design, synthesize and characterize novel hybrid organic-inorganic compounds. The hybrid organic-inorganic compounds CHAZnBr3 and (CHA)2ZnBr4 were synthesized for the first time, to the best of our knowledge, and will be the focus of this thesis. The two new hybrid organic-inorganic compounds were structurally characterized by X-ray Diffraction (XRD) and thermally characterized by Thermal Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The first compound, CHAZnBr3, could be determined to be orthorhombic at 298 K. The compound was found to be thermally stable up 490 K, and to undergo a phase transition at 445 K. The second compound, (CHA)2ZnBr4, could not be fully structurally solved at either 100 K or 298 K. The compound was found to be thermally stable up to 490 K, and to undergo a phase transition at 230 K. Further characterization will be needed to better understand the properties of these two compounds and their possible applications.
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Liu, Tianyu. "Perovskite Solar Cells fabrication and Azobenzene Perovskite synthesis: a study in understanding organic-inorganic hybrid lead halide perovskite." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1576840261464488.
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Sahin, Tiras Kevser. "Magnetic field effect and other spectroscopies of organic semiconductor and hybrid organic-inorganic perovskite devices." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6495.
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This thesis consists of three main studies: magnetic field effects in thermally activated delayed fluorescent (TADF) organic light emitting diodes (OLEDs), magnetic field effects in bipolar and unipolar polythiophene (P3HT) devices and a study of hybrid organic/inorganic perovskite devices.
Spin-dependent transport and recombination processes of spin-pair species have been detected by magnetic field effect (MFE) technique in carbon-based semi- conductor devices. Magneto-electroluminescence (MEL) and magneto-conductivity have been measured as a function of the applied magnetic field, B, in light emitting diodes. TADF materials have been used instead of simple fluorescent materials in OLEDs. We have observed very large magnetic response with TADF materials.
The second study is magnetic field effects of regio-regular P3HT based OLED devices. P3HT is a well known semiconducting polymer, and its electrical properties such as magneto-conductance can be affected by an applied magnetic field. P3HT was chosen because it exhibits a sign change in magnetoresistance (MR) as the bias is increased. Unipolar and bipolar devices have been fabricated with different electrode materials to understand which model can be best to explain organic magnetoresistance effect, possibly depending on the operating regime of the device. Transport and luminescence spectroscopies were studied to isolate the different mechanisms and identify their fingerprints.
The third study is on hybrid organic-inorganic perovskite devices. With the potential of achieving very high efficiencies and the very low production costs, perovskite solar cells have become commercially attractive. Scanning electron microscopy (SEM) images and absorption spectrum of the films were compared in single-step solution, two-step solution and solution-assisted vapor deposition techniques. Grain size, morphology and thickness parameters of perovskite films were studied within these techniques. Perovskite solar cells were fabricated and their efficiencies were measured.
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Hentz, Olivia Dolores. "The uncommon nature of point defects in organic-inorganic Perovskite solar cells." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/117781.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 133-148).
Organic-inorganic perovskite solar cells (PSCs) have shown enormous success in the past decade, increasing in power conversion efficiency from ~4% in 2009 to >22%. One of the critical properties that contributed to this success is "defect tolerance": in organic-inorganic perovskites, the majority of point defects with low formation energy are shallow, with energies within or near the conduction or valence band. Defects with deep states, which act as electronic traps, are expected to be much less common due to their high formation energies. In this thesis, we demonstrate that, despite the preference for shallow defects, point defects play an integral role in materials properties and PSC device performance. We first study the role of point defects on nanoscale luminescence properties of inorganic-organic perovskites by using cathodoluminescence in scanning transmission electron microscopy (STEM). By correlating local luminescence properties with compositional variations using STEM, we demonstrate that iodide segregation induced by the electron beam is correlated with a spatially-localized high-energy emission. Similar high-energy emission has been observed in photoluminescence (PL) measurements for films made in the presence of excess methyl ammonium iodide, demonstrating that the observed defect segregation is relevant to practical device design. Next, we study the effects of directional point defect segregation under an applied electric field on current extraction from PSCs. Specifically, we use electron beam-induced current measurements in a scanning electron microscope to measure the inhomogeneity in current extraction before and after forward biasing the device. These measurements point to preferential defect migration at extended defects and allow us identify low frequency capacitive elements related to compensation of charged defect segregation under applied biasing. Finally, we directly track the migration of deep defects in PSCs through photoluminescence mapping of laterally biased perovskite films. Removal of defect states by mild voltage biasing results in over an order of magnitude increase in luminescence. Using Monte Carlo simulations of defect drift and diffusion to model these time dependent luminescence maps, we extract the mobility of these point defects and provide evidence of demonstrates the ways in which deep and shallow defects play a critical role in PSCs and suggests that, despite their "defect tolerance," the ultimate stability and performance of PSCs will be dependent on either minimizing the presence of point defects in these materials or inhibiting defect migration.
National Science Foundation (U.S.) under award number DMR-141-9807
by Olivia Dolores Hentz.
Ph. D.
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Ralaiarisoa, Maryline. "Electronic properties of hybrid organic-inorganic perovskite films: effects of composition and environment." Doctoral thesis, Humboldt-Universität zu Berlin, 2019. http://dx.doi.org/10.18452/20194.
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Der Schwerpunkt der vorliegenden Arbeit liegt in der Charakterisierung der elektronischen Eigenschaften von hybriden organisch-anorganischen Perowskit (HOIP)-Schichten während der Schichtbildung und in verschiedenen Umgebungen mittels Photoelektronenspektroskopie (PES). Insbesondere wird der Methylammonium-Blei-Iodid-Chlorid-Perowskit (MAPbI3-xClx) untersucht.
Als erstes werden Änderungen in den elektronischen Eigenschaften, der Zusammensetzung, sowie der Kristallstruktur mittels PES, Flugzeit-Sekundärionenmassenspektrometrie, sowie Röntgendiffraktometrie mit streifendem Einfall analysiert. Die Resultate weisen auf die entscheidende Rolle von Chlor im texturierten Wachstum der Perowskitschicht hin. Die auskristallisierte Perowskitschicht weist eine stärkere n-Typ Eigenschaft auf, welche auf die Änderung der Zusammensetzung während der Schichtbildung zurückgeführt werden kann. Außerdem beweisen die Ergebnisse eindeutig die Ablagerung von Chlor an der Grenzfläche zwischen der Perowskitschicht und dem Substrat. Zweitens werden die separaten Einflüsse von Wasser, Sauerstoff, und Umgebungsluft auf die elektronischen Eigenschaften von MAPbI3-xClx-Schichtoberflächen untersucht. Bereits geringste Wassermengen ähnlich wie im Hochvakuum oder in inerter Umgebung können eine reversible Reduzierung der Austrittsarbeit hervorrufen. Höherer Wasserdampf-Partialdruck führt zu einer Verschiebung des Valenzbandmaximums (VBM) weit vom Fermi-Niveau, sowie zu einer Reduzierung der Austrittsarbeit. Im Gegensatz dazu führt eine Sauerstoffexposition zu einer Verschiebung des VBM in Richtung des Fermi-Niveaus und zu einer Steigerung der Austrittsarbeit. Analog kommt es zu einer Verschiebung von bis zu 0.6 eV bei einer Exposition gegenüber Umgebungsluft, was den vorwiegenden Einfluss von Sauerstoff demonstriert.
Die vorliegenden Untersuchungen betonen den kritischen Einfluss der Schichtbildung, der Zusammensetzung, sowie der Umgebungsbedingungen auf die elektronischen Eigenschaften von HOIP.The present thesis aims at characterizing the electronic properties of solution-processed hybrid organic-inorganic perovskites (HOIPs) in general, and the HOIP methyl ammonium (MA) lead iodide-chloride (MAPbI3-xClx) films, in particular, at different stages, namely from its formation to its degradation, by means of photoelectron spectroscopy (PES). Firstly, the formation of MAPbI3-xClx films upon thermal annealing is monitored by a combination of PES, time-of-flight secondary ion mass spectrometry, and grazing incidence X-ray diffraction for disclosing changes in electronic properties, film composition, and crystal structure, respectively. Overall, the results point to the essential mediating role of chlorine in the formation of a highly textured perovskite film. The film formation is accompanied by a change of composition which leads to the film becoming more n-type. The accumulation of chlorine at the interface between perovskite and the underlying substrate is also unambiguously revealed. Secondly, the separate effects of water and oxygen on the electronic properties of MAPbI3-xClx film surfaces are investigated by PES. Already low water exposure – as encountered in high vacuum or inert conditions – appears to reversibly impact the work function of the film surfaces. Water vapor in the mbar range induces a shift of the valence band maximum (VBM) away from the Fermi level accompanied by a decrease of the work function. In contrast, oxygen leads to a VBM shift towards the Fermi level and a concomitant increase of the work function. The effect of oxygen is found to predominate in ambient air with an associated shift of the energy levels by up to 0.6 eV. Overall, the findings contribute to an improved understanding of the structure-property relationships of HOIPs and emphasize the impact of least variation in the environmental conditions on the reproducibility of the electronic properties of perovskite materials.
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Hyung, Do Kim. "Development of Highly Efficient Organic-Inorganic Hybrid Solar Cells." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225630.
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Guo, Xin. "PREPARATION AND PROPERTY STUDIES OF ORGANIC-INORGANIC HYBRID SEMICONDUCTOR MATERIALS FOR SOLAR CELL APPLICATIONS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1458736601.
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FU, QIANG FU. "POLYMER-TEMPLATED NUCLEATION AND CRYSTAL GROWTH OF PEROVSKITE FILM AND CONDUCTIVE IONOMER DOPED PEROVSKITE FILLM FOR HIGH PERFORMANCE OF ORGANIC-INORGANIC HYBRID PEROVSKITE SOLAR CELLS." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1495207539153854.
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Hou, Yi [Verfasser], and Christoph [Gutachter] Brabec. "Rational Interfaces Design of Efficient Organic–inorganic Hybrid Perovskite Solar Cells / Yi Hou ; Gutachter: Christoph Brabec." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2017. http://d-nb.info/1136133194/34.
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Öz, Senol [Verfasser]. "Process-, Solvent- and Chemical Engineering for Solution Processed Organic-Inorganic Lead Halide Perovskite Solar Cells / Senol Öz." München : Verlag Dr. Hut, 2018. http://d-nb.info/1170473601/34.
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Bandara, Nilantha. "Guest intercalation into metal halide inorganic-organic layered perovskite hybrid solids and hydrothermal synthesis of tin oxide spheres." Master's thesis, Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-10312008-212759.
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Möllmann, Alexander [Verfasser]. "Nanostructured Metal Oxide Thin Films as Electron Transport Material for Inorganic-Organic Hybrid Perovskite Solar Cells / Alexander Möllmann." München : Verlag Dr. Hut, 2020. http://d-nb.info/1219478067/34.
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Safdari, Majid. "Chemical Structure and Physical Properties of Organic-Inorganic Metal Halide Materials for Solid State Solar Cells." Doctoral thesis, KTH, Tillämpad fysikalisk kemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-199951.
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Abstract Methylammonium lead (II) iodide has recently attracted considerable interest which may lead to substantial developments of efficient and inexpensive industrial photovoltaics. The application of this material as a light-absorbing layer in solid-state solar cells leads to impressive efficiency of over 22% in laboratory devices. However, for industrial applications, fundamental issues regarding their thermal and moisture stability need to be addressed. MAPbI3 belongs to the perovskite family of materials with the general formula ABX3 ,where is the organic cation (methylammonium) which is reported to be a major source of instability. In this work, a variety of alkyammonium lead (II) iodide materials have been synthesized by changing the organic cation, to study the relationship between the structural and physical properties of these materials. [(A)PbI3] and (A)PbI4 series were studied. Three dimensional (3D) networks (MAPbI3,MAPbBr3), two dimensional (2D) layered systems (BdAPbI4, HdAPbI4, OdAPbI4), and one dimensional (1D) columns (EAPbI3, PAPbI3, EAPb2I6) were found for the materials. [PbI6] octahedral structural units were repeated through the material network depending on the dimensionality and connectivity of the materials. Where a bulkier cation was introduced, the crystallographic unit cell increased in size which resulted in lower symmetry crystals. The connectivity of the unit cells along the material networks was found to be based on corner-sharing and face-sharing. Lower dimensionality resulted in larger bandgaps and lower photoconductivity, and hence a lower light conversion efficiency for the related solar cells. The thermal and moisture stability was greater in the 1D and 2D materials with bulkier organic cations than with methylammonium. In total, an overview is provided of the relationship between the chemical dimensionality and physical properties of the organic-inorganic lead halide materials with focus on the solar cell application.Svenska sammandrag: Metylammoniumbly(II)jodid har under de senaste åren genererat ett stort intresse som ett möjligt material for utveckling av effektiva och på industriell skala billiga solceller. Detta material har använts som ljusabsorberande skikt i fasta solceller med imponerande omvandlingseffektiviteter på över 22% för solceller i laboratorieskala. För att denna nya typ av solceller ska bli intressanta för produktion på industriell skala, så behöver grundläggande frågeställningar kring materialens stabilitet avseende högre temperaturer och fukt klargöras. MAPbI3 har formellt perovskitstruktur med den allmänna formel ABX3, där A utgörs av den organiska katjonen (metyammoniumjonen) och som kan kopplas till materialets instabilitet. I denna avhandling har olika alkylammoniumbly(II)jodidmaterial syntetiserats där den organiska katjonen modifierats med syftet att studera växelverkan mellan struktur och fysikaliska egenskaper hos de resulterande materialen. Material av olika dimensionalitet erhölls; tredimensionella (3D) nätverk (MAPbI3, MAPbBr3), tvådimensionella (2D) skiktade strukturer (BdAPbI4, HdAPbI4, OdAPbI4), och endimensionella (1D) kedjestrukturer (EAPbI3, PAPbI3, EAPb2I6). Flera nya lågdimensionella material (2D och 1D) tillverkats och karaktäriserats för första gången. Enkristalldiffraktometri har använts för att erhålla materialens atomära struktur. Strukturen hos material tillverkade i större mängder konfirmerades genom jämförelse mellan resultat från pulverdiffraktion och enkristalldiffraktion. Den oktaedriska strukturenheten [PbI6] utgör ett återkommande tema i materialen sammankopplade till olika dimensioner. Då större organiska katjoner används karaktäriseras i regel strukturerna av större enhetsceller och lägre symmetri. De lågdimensionella materialen ger typiskt störe elektroniskt bandgap, lägre fotoinducerad ledningsförmåga och därför sämre omvandlingseffektiviteter då de används i solceller. De lågdimensionella materialen (1D och 2D) som baseras på de större organiska katjonerna uppvisar bättre stabilitet med avseende på högre tempereratur och fukt. De tvådimensionella materialens elektroniska struktur har karaktäriserats med hjälp av röntegenfotoelektronspektroskopi, liksom röntgenabsorptions- och emissionsspektroskopi. Resultat från teoretiska beräkningar stämmer väl överens med de experimentella resultaten, och de visar att materialens valensband huvudsakligen består av bidrag från atomorbitaler hos jod, medan atomorbitaler från bly främst bidrar till edningsbandet. Sammantaget erbjuder avhandlingen en översikt av sambandet mellan kemisk dimensionalitet och fysikaliska egenskaper hos ett antal organiska/oorganiska blyhalogenidmaterial med fokus på tillämpning i solceller.
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ANUSIT, KAEWPRAJAK. "Improvement of Photovoltaic Properties of Solar Cells with Organic and Inorganic Films Prepared by Meniscuc Coating Technique." Kyoto University, 2019. http://hdl.handle.net/2433/242322.
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Yu, Yue. "Thin Film Solar Cells with Earth Abundant Elements: from Copper Zinc Tin Sulfide to Organic-Inorganic Hybrid Halide Perovskite." University of Toledo / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1513289830601094.
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Mabiala, Floyd Lionel. "Photo-physical properties of lead-tin binary Perovskite thin films." University of Western Cape, 2021. http://hdl.handle.net/11394/8002.
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>Magister Scientiae - MScOrganic-inorganic lead-based perovskite has exhibited great performance in the past few years. However, the lead (Pb) embedded in those compounds is a significant drawback to further progress, due to its environmental toxicity. As an alternative, tin (Sn) based-perovskites have demonstrated promising results in terms of electrical and optical properties for photovoltaic devices, but the oxidation of tin ion- from stannous ion (Sn2+) to stannic ion (Sn4+) presents a problem in terms of performance and stability when exposed to ambient conditions. A more feasible approach may be in a Pb-Sn binary metal perovskite in pursuit of efficient, stable perovskite solar cells (PSCs) with reduced Pb-content, as compared to pure Pb- or Sn-based PSCs. Here, we report on the deposition of a Pb-Sn binary perovskite by sequential chemical vapor deposition.
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Chen, Haiwei [Verfasser], Christoph [Akademischer Betreuer] Brabec, and Dirk [Gutachter] Schubert. "Interface and composition engineering towards stable and efficient organic-inorganic perovskite solar cells / Haiwei Chen ; Gutachter: Dirk Schubert ; Betreuer: Christoph Brabec." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2018. http://d-nb.info/1172972400/34.
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Liu, Mingzhen. "Planar heterojunction perovskite solar cells via vapour deposition and solution processing." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:89a275a8-5ec8-442c-a114-246a44dbd570.
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Hybrid organic-inorganic solar photovoltaic (PV) cells capable of directly converting sunlight to electricity have attracted much attention in recent years. Despite evident technological advancements in the PV industry, the widespread commercialisation of solar cells is still being mired by their low conversion efficiencies and high cost per Watt. Perovskites are an emerging class of semiconductors providing a low-cost alternative to silicon-based photovoltaic cells, which currently dominate the market. This thesis develops a series of studies on “all-solid state perovskite solar cells” fabricated via vapour deposition which is an industrially-accessible technique, to achieve planar heterojunction architectures and efficient PV devices. Chapter 2 presents a general outlook on the operating principles of solar cells, delving deeper into the specific operational mechanism of perovskite solar cells. It also explores the usual methods employed in the fabrication of perovskite thin films. Chapter 3 describes the experimental procedures followed during the fabrication of the individual components constituting the device from the synthesis of the precursors to the construction of the functioning perovskite PV devices. Chapter 4 demonstrates pioneering work involving the dual-source vapour deposition (DSVD) of planar heterojunction perovskite solar cells which generated remarkable power conversion efficiency values surpassing 15%. These significant results pave the way for the mass-production of perovskite PVs. To further expand the range of feasible vapour deposition techniques, a two-layer sequential vapour deposition (SVD) technique is explored in Chapter 5. This chapter focusses on identifying the factors affecting the fundamental properties of the vapour-deposited films. Findings provide an improved understanding of the effects of precursor compositions and annealing conditions on the films. Chapter 5 concludes with a comparison between SVD and DSVD fabricated films, highlighting the benefits of each vapour deposition technique. Furthermore, hysteretic effects are analysed in Chapter 6 for the perovskite PV devices fabricated based on different structural configurations. An interesting discovery involving the temporary functioning of compact layer-free perovskite PV devices suggests the presence of a built-in-field responsible for the hysteresis of the cells. The observations made in this chapter yield a new understanding of the functionality of individual cell layers. Combining the advantages of the optimum vapour deposition technique established in Chapter 4 and Chapter 5, with the enhanced understanding of perovskite PV cell operational mechanism acquired from Chapter 6, an ongoing study on an “all-perovskite” tandem solar cell is introduced in Chapter 7. This demonstration of the “all-perovskite” tandem devices confirms the versatility of perovskites for a broader range of PV applications.
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Ralaiarisoa, Maryline [Verfasser], Norbert [Gutachter] Koch, Emil [Gutachter] List-Kratochvil, and Philip [Gutachter] Schulz. "Electronic properties of hybrid organic-inorganic perovskite films: effects of composition and environment / Maryline Ralaiarisoa ; Gutachter: Norbert Koch, Emil List-Kratochvil, Philip Schulz." Berlin : Humboldt-Universität zu Berlin, 2019. http://d-nb.info/1191753697/34.
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Rathod, Siddharth Narendrakumar. "Structure Stability and Optical Response of Lead Halide Hybrid Perovskite Photovoltaic Materials: A First-Principles Simulation Study." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1496189488934021.
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Su, Ruey-Yuan, and 蘇睿元. "Fabrication of single-crystalline organic-inorganic hybrid perovskites thin films." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/5p4zm7.
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碩士國立中山大學
材料與光電科學學系研究所
107
In recent years, there has been a crystalline material - "organic-inorganic hybrid perovskite " structure which has been taken as the potential candidate of future solar cells. These perovskite solar cells have attracted the scientist’s attention due to their easy fabrication process and rapid growth conversion efficiency. Thus, our study is focus on perovskite structure. There are two parts of our work. In the first part, we use inverse temperature crystallization method to grow perovskite single crystals. In the second part, we added Tetrahydrothiophene 1-oxide (THTO) in perovskite precursor solution and use spin-coating method to fabricate thin films. We found that THTO can enhance the prefer orientation for thin films which may be better for device applications. In the first study, we fabricate various types of perovskite single crystals successfully via inverse temperature crystallization such as MAPbBr3, MAPbI3, MA1-xCsxPbI3 and MAPbI3-xClx. The crystal structure has been confirmed by X-ray diffraction analysis and the crystal quality has been analyzed by rocking curve analysis (High- Resolution XRD). We also use SEM, OM to analyze their surface morphology. In our second work, we can observe the films fabricated by adding THTO in solution using X-ray diffraction analysis, was performed prefer orientation on (110) and (220) diffraction angles, and the grain size for adding THTO in the solution is larger than another using SEM images analysis.
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Hou, Wen-Chi, and 侯文棋. "Studies on the synthesis and physical properties of organic-inorganic hybrid perovskites polymer nanocomposite." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/71350993476127674743.
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碩士元智大學
化學工程學系
91
Abstract In this study, the organic-inorganic layer perovskite compound (C6H13NH3)2(CH3NH3)m-1PbmBr3m+1 were composed. We can control the inorganic layer thickness by changing the stoichiometry of reactants and reacting environment. They are characterized by use of instrument analysis in order to investigate the relationship between inorganic layers and physical properties and electrical properties. Because of the solubility of this materials we can synthesis polymer nanocompoiste in solution. Then we discuss the effect with different nanodisperse. XRD results showed that the d-spacing increases at constant value with increase the inorganic layers which identified our expectation. The UV-Vis and PL results had red-shift when increase the inorganic layers. The phenomena show that the energy gap can be changed by tunneling the layer structure. By dielectric analysis we understand the dielectric constant is corresponding to the numbers of inorganic layers. Conductivity relaxation time distribution increase when the numbers of inorganic layer increase. We also identified the carrier mobility will increase when the numbers of inorganic layers increase. In polymer nanocompoist, we found different nanodisperse. The UV-Vis and PL spectrum had substantial change when adding polymer and different layer structure. From DEA analysis, we found that different polymer will cause different carrier hoping activity energy and conductivity relaxation conversion temperature.
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Perumal, Packiyaraj, and 培其亞. "Investigation of Novel Optoelectronic Device Fabrication based on 2-D Layered Semiconductors and Organic-Inorganic Perovskites." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/nram9a.
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博士國立臺灣大學
物理學研究所
106
Atomically thin two-dimensional (2D) layered semiconductors, such as transition metal dichalcogenides (TMDs) have attracted tremendous interest in nanoscale semiconductor devices owing to their attractive scrutiny both in academic and industrial interest. In this dissertation, we have designed novel optoelectronic devices based on 2D materials such as SnS2, SnSe2, SnSSe, MoS2, GaSe, and their heterostructures. In addition, low-dimensional organic-inorganic (O-I) semiconductors frameworks have been designed for highly-promising optoelectronic devices owing to the excellent light emission. Through our great efforts, we not only discovered many fruitful and interesting optoelectronic properties, but also studied and discussed the potentials for the diversified applications in the future. Our results are classified as 4 main topics and summarized as followings. 1. Ultra-thin layered ternary single crystals [Sn(SxSe1-x)2] with bandgap engineering for high performance photo transistors on versatile substrates Two-dimensional (2D) ternary semiconductor single crystals, an emerging class of new materials, have attracted significant interest recently owing to their great potential for academic interest and practical applications. In addition to other types of metal dichalcogenides, 2D tin dichalcogenide are also important layered compounds with similar capabilities. Yet, multi-elemental single crystals enable to assist multiple degrees of freedom for dominant physical properties via ratio alteration. Herein, we report the growth of single crystals Se-doped SnS2 or SnSSe alloys, and demonstrate their capability for the fabrication of photo-transistors with high performance. Based on exfoliation from bulk high quality single crystals, we establish the characteristics of few-layered SnSSe in structural, optical, and electrical properties. Moreover, few-layered SnSSe photo-transistors were fabricated on both rigid (SiO2/Si) and versatile polyethylene terephthalate (PET) substrates and their optoelectronic properties were examined. SnSSe as a photo-transistor was demonstrated to exhibit a high photoresponsivity of about 6000 AW-1 with ultra-high photogain (η) ∼8.8×105, fast response time ∼9 ms, and specific detectivity (D*) ∼8.2×1012 J. These unique features are much higher than those of recently published photo-transistors configured with other few-layered 2D single crystals, making ultrathin SnSSe as a highly qualified candidate for next-generation optoelectronic applications. 2. Whispering Gallery Mode Lasing from Self-Assembled Hexagonal Perovskite Single Crystals and Porous Thin Films Decorated by Dielectric Spherical Resonators Lasing in self-assembled hybrid organic-inorganic lead halide perovskites semiconductors has attained intensive research for low cost and high performance optoelectronic devices due to their inherent outstanding optical response. However, to achieve the controllable laser action from a small single crystal remains as a challenging issue. Here, we present a novel technique to fabricate self-assembled high-quality hexagonal perovskite single crystals for realizing room-temperature near-infrared whispering-gallery-mode (WGM) laser action. Quite interestingly, the lasing spectrum for an individual CH3NH3PbI3 hexagonal single crystals encompasses the aspects of high quality factor (Q) and low threshold WGM lasing around 1200 and 26.8 μJ/cm2, respectively. In addition, we demonstrate that when the porous perovskite thin films were decorated with dielectric spheres, the laser oscillation can be achieved through the coupling of WGM with perovskite gain material. We found that the lasing spectra can be well manipulated by the size of hexagonal single crystals and SiO2 spheres. Moreover, the discovered laser action and chemical stability of hexagonal single crystal perovskites not only render them significant practical use in highly efficient near infrared emitting devices for laser photonics, solid-state lighting and display applications, but also provide a potential extension towards various optoelectronic devices. 3. Diverse Functionalities of Vertically Stacked Graphene/Single layer n-MoS2/SiO2/p-GaN Heterostructures Integrating different dimentional materials on vertically stacked p-n hetero-junctions have facinated a considerable scrunity and can open up excellent feasibility with various functionalities in opto-electronic devices. Here, we demonstrate that vertically stacked p-GaN/SiO2/n-MoS2/Graphene heterostructures enable to exhibit prominent dual opto-electronic characteristics, including efficient photo-detection and light emission, which represents the emergence of a new class of devices. The photoresponsivity was found to achieve as high as ~10.4 AW-1 and the detectivity and external quantum efficiency were estimated to be 1.1×1010 Jones and ~ 30%, respectively. These values are superier than most reported hererojunction devices. In addition, this device exhibits as a self-powered photodetector, showing a high responsivity and fast response speed. Moreover, the device demonstrates the light emission with low turn-on voltage (~ 1.0 V) which can be realized by electron injection from graphene electrode and holes from GaN film into monolayer MoS2 layer. These results indicate that with a suitable choice of band alignment, the vertical stacking of materials with different dimentionalities could be significant potential for integration of highly efficient heterostructures and open up feasible pathways towards integrated nanoscale multi-functional optoelectronic devices for a variety of applications. 4. Type II Band Alignment of Vertically Stacked Few-Layered GaSe-SnS2 van-der Walls p-n Heterostructures for High Performance Opto-electronic Devices Atomically thin vertically stacked two dimentional (2D) van der Walls (vdW) heterostructures have recently emerged as a new kind of devices with intriguing novel phenomena for both academic and industrial interests. However, the lack of p-type materials remains as a challenge issue to create useful devices for the realization of practical applications. Interestingly, GaSe is an intrinsic 2D p-type layered compound with a wide optical transparency, and it has a direct band gap with regardless of the thickness. Here, we demonstrate the first vertically stacked few-layered p-type gallium selenide (GaSe) and n-type tin disulphide (SnS2) vdW heterostructure for high performance opto-electronic applications. The electrical characteristic of the p-n junction reveals an excellent current rectification behaviour. It is found that the phototransistors based on few-layered GaSe/SnS2 p-n junction show superior performance with the responsivity, external quantum efficiency and specific detectivity as high as ~ 35 AW-1, 62% and 8.2×1013 J, respectively, which exceed all the reported values derived from 2D materials. In addition, the GaSe/SnS2 p-n junction can also serve as a photovoltaic cell with an high power conversion efficiency of about ~ 2.84%. Moreover, the few-layered GaSe/SnS2 p-n heterostructures can be deposited on versatile substrates with excellent performance, such as flexible polyethylene terephthalate (PET). Through a detailed study, the underlying mechanism responsible for the high performance of opto-electronic devices on few-layered GaSe/SnS2 can be attributed to the unique type II band alignment and excellent quality of interface. The few-layered p-GaSe/n-SnS2 vdW heterojunctions shown here demonstrate a new illustration for the stacking of 2D materials, which is very useful for the development of next generation novel opto-electronic devices.
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LIN, YA-LIANG, and 林亞諒. "Characterization of organic-inorganic hybrid perovskite thin films." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/6v3a5u.
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碩士明志科技大學
電子工程系碩士班
107
Organic-inorganic hybrid perovskites have been studied intensively due to their high absorption coefficient, high efficiency, long carrier diffusion length, facile fabrication process, and low material cost. Such hybrid perovskites have been applied for various optoelectronic devices including photovoltaic cells, light-emitting diodes, and photodetectors. Organic-inorganic hybrid perovskites exhibit the general formula ABX3, where A is a monovalent organic cation, B is Pb2+ or Sn2+, and X is a halide anion. In this thesis, CH3NH3PbI3 perovskite thin films with different concentrations were prepared using one-step deposition method. Temperature-dependent photoluminescence (PL) were carried out in the temperature range from 10 to 300 K. The carrier emission mechanism, carrier redistribution effect, electron-phonon renormalization and thermal expansion effect on the band-gap are discussed to investigate the thermal behaviors of peak energy, full width at half maximum, and intensity of the PL spectra measured from our samples.
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Tsai, Hsin-Yu, and 蔡欣妤. "All-Inorganic Perovskite Quantum Dots for Organic Light-Emitting Diodes." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/wj8eqf.
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碩士國立臺灣大學
化學研究所
106
White light-emitting diodes (LEDs) is widely used as backlighting components in the modern liquid-crystal display (LCD). For high-quality backlight, color saturation and color gamut are the key indicators, which affect the color performance display devices. Perovskite CsPbBr3 quantum dots (QDs) are regarded as the most promising narrow-band green-emitting material for wide-color-gamut backlight displays because of their high photoluminescence quantum yield (PLQY) and the narrow-band emission with a full width at half maximum (FWHM) of ∼20 nm. Despite their growing popularity, CsPbBr3 QDs have several shortcomings such as the existence of surface trap states, poor thermal and aqueous stability, and the solution QDs are unsuitable for direct use in on-chip white LEDs. Here, the surface treatment of perovskite CsPbBr3 QDs with thiocyanate salts (SCN-) toward high brightness and stable narrow-band green emission was investigated. After the treatment, a high quantum yield and stable narrow-band perovskite CsPbX3-SCN was obtained. The product exhibited several advantages, including high absolute PLQY of 94%, enhaced photoluminescence intensity, and air stability. Moreover, CsPbBr3-SCN perovskite QDs are potential emitters for QLED electroluminescent displays. However, balancing their performance and their environmentally friendly property is challenging. To achieve such balance, we demonstrated an easy hot-injection method to synthesize Cs(Pb1-xSnx)Br3 QDs by partially replacing the toxic Pb2+ with the highly stable Sn4+. Meanwhile, the absolute PLQY of Cs(Pb0.67Sn0.33)Br3 QDs increased from 45% to 83% compared with CsPbBr3. Based on a femtosecond transient absorption, time-resolved PL, and single-dot spectroscopies, we conclude that the PLQY enhancement is due to the reduction of trion formation in perovskite QDs with Sn4+ substitution. Moreover, the CsPbBr3-SCN solution that surface treatment with thiocyanate salt increased the performance of QLED devices based on these highly luminescent cesium lead halide perovsike QDs, exhibiting a central emission wavelength of 516 nm, a current efficiency of 4.2 cd/A, and an external quantum efficiency of 1.4% which is the higher values among the CsPbBr3 perovskite QLED devices.
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FU, LIANG-CHUN, and 傅亮淳. "Aminosilane Assisted Synthesis of Nanoparticles for Organic-Inorganic Perovskite Resistive Ｍemory." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/6j2jkw.
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Chen, Yen Chu, and 陳燕儲. "Organic-Inorganic Hybrid Perovskite Solar Cell with Modified Two-Step Solution Processing." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/35419839185925282573.
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Tseng, Shih-Wei, and 曾世維. "The Inorganic Copper Thiocyanate Material Applied to Organic Iodide Lead Perovskite Solar Cells." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/14836749479901430586.
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碩士國立臺南大學
電機工程學系碩博士班
104
This post thesis research, we will successfully applied the perovskite copper thiocyanate solar cell P-type buffer layer, we will be formulated as a powdercopper thiocyanate solution was spin-coated to be made into film, and from energy level (Conduction band) using copper thiocyanate can be seen also reduce carrier recombination, and therefore can have a higher open-circuit voltage and short circuit current density, conversion efficiency of the element can be improved- We use the PEDOT: PSS element made of the photoelectric conversion efficiency of only 11%, and we can see that the use of copper thiocyanate conversion efficiency can be increased to 15.1%. We then without annealing manner, successfully applied to the flexible substrate copper thiocyanate, efficiency can reach 7%.
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Kuo, Chia-Tien, and 郭家典. "The study of inverse temperature crystallization mechanism of organic-inorganic hybrid perovskite crystals." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/5p4eqe.
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碩士國立中山大學
材料與光電科學學系研究所
107
The organic-inorganic hybrid perovskite structure is a novel semiconductor, which has the advantages of simple process and excellent photoelectric characteristics, and attracts lots attentions in recent years. Among them, in 2015, Saidaminov, et al. found that in a specific solution, single crystals can be precipitated in perovskite solution in a short time by raising the temperature, called inverse temperature crystallization. This finding provides a fast and efficient way to grow perovskite single crystals. However the mechanism is not fully understood yet. This study aims to investigate the inverse temperature crystallization mechanism of organic-inorganic hybrid perovskite crystals. The issue was approached by the solution measured by UV-Vis absorption spectroscopy. It is found that higher halide coordination number complex of Pb2+ was increased in the solution with higher concentrations of either halide ion or lead ion. Moreover, to raise temperature will also cause higher halide coordination number complex of Pb2+ to be formed. Our results reveal the mechanism for the inverse temperature crystallization: Raising temperature causes the break of the bonding between Pb2+ and the solvent molecule, hence towards higher halide coordination number complex, which favors the formation of MAPbI3 crystals. Moreover, we studies the intermediate compounds constituted of MAI, PbIb2 and the solvent ( DMSO, DMF, or GBL) by thermogravimetric analysis (TGA) and XRD analysis. Our results indicates the three intermediate structures will be decomposed at temperature of ~ 110 C (GBL), 120 C (DMF), and 170 C (DMSO), respectively.
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Dragomir, Vlad Alexandru. "Étude de la dynamique vibrationnelle de pérovskites 2D hybrides organiques-inorganiques par spectroscopie Raman." Thèse, 2018. http://hdl.handle.net/1866/22207.
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Chen, You-Cheng, and 陳佑承. "Fabrication of Lead Halide Perovskite Organic/Inorganic Hybrid Solar Cells with Thick Photoactive Layer." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/gmznxn.
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碩士國立清華大學
光電工程研究所
102
This paper proposed a low temperature, solution process, simple process, a large area of the lead halide perovskite organic/inorganic hybrid solar cell. In this paper, in which the use of lead halide perovskite as the photoactive layer. With the high solubility PbCl2 in DMSO to increase the concentration of the precursor solution, and construct organic / inorganic hybrid solar cell. Our device configuration:Glass/ITO/PEDOT:PSS/Perovskite/PCBM/Al belong to normal structure. Suitably selected the hole and the electron transport layer by spin coating and dried to optimize conditions for the performance of the solar cell of the present paper is better. In this paper, Construction of the solar cell efficiency of up to 7.0 %, short-circuit current of 18.1 mA/cm2 has excellent performance. Lead halide perovskite organic / inorganic hybrid solar cell laden with good efficiency and performance advantages of a large area can be to facilitate the production of large-area components toward future development.
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Kuo, Chen-Shien, and 郭政憲. "Influence of Mesoporous TiO2 on the Carrier Dynamics of Organic-Inorganic Lead Trihalide Perovskite." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/hu3q8y.
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碩士國立交通大學
光電工程研究所
105
From SEM images of perovskite, we show the morphologies and crystal structures of three fabrication and the enhancement of Solvent Engineering, Two Step and LPCVD with TiO2 layer.The absorption of three fabrication becomes higher and the peak of PL is overlapped at 750 nm when inserting the TiO2 layer.The exciton lifetime of perovskite is influenced by the wavelength dependence and power dependence when inserting the mesoporous TiO2 layer. Even more, the influence of the stability and different crystal arrangement shown from the S-polarized and P-polarized orientation.The carrier lifetime of three fabrication indicates different carrier lifetime, it corresponds to the crystallization of Solvent Engineering and LPCVD are enhanced by the mesoporous TiO2 layer in the orientation of parallel to the substrate.