Дисертації з теми "Solar cells- Light absorption"
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Yang, Qingyi. "Broadband light absorption enhancement in organic solar cells." HKBU Institutional Repository, 2014. https://repository.hkbu.edu.hk/etd_oa/54.
Повний текст джерелаFang, Liping. "Enhancing light absorption in silicon solar cells by fluorescent molecules." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/370511/.
Повний текст джерелаLan, Weixia. "Light harvesting and charge collection in bulk heterojunction organic solar cells." HKBU Institutional Repository, 2016. https://repository.hkbu.edu.hk/etd_oa/318.
Повний текст джерелаDunbar, Ricky. "Using metallic nanostructures to trap light and enhance absorption in organic solar cells." Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-142241.
Повний текст джерелаEllaboudy, Ashton. "ENHANCEMENT OF LIGHT ABSORPTION EFFICIENCY Of SOLAR CELL USING DUAL." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/672.
Повний текст джерелаCurtin, Benjamin Michael. "Photonic crystal back-reflectors for light management and enhanced absorption in a-Si:H solar cells." [Ames, Iowa : Iowa State University], 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1468075.
Повний текст джерелаBeyer, Beatrice. "Architectural Approaches for the Absorption Layer and their Impact on Organic Solar Cells." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-133594.
Повний текст джерелаMüller, Thomas Christian Mathias [Verfasser], Uwe [Akademischer Betreuer] Rau, and Christoph [Akademischer Betreuer] Brabec. "Light absorption and radiative recombination in thin-film solar cells / Thomas Christian Mathias Müller ; Uwe Rau, Christoph Brabec." Aachen : Universitätsbibliothek der RWTH Aachen, 2015. http://d-nb.info/1128598019/34.
Повний текст джерелаDunbar, Ricky [Verfasser], and Lukas [Akademischer Betreuer] Schmidt-Mende. "Using metallic nanostructures to trap light and enhance absorption in organic solar cells / Ricky Dunbar. Betreuer: Lukas Schmidt-Mende." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2012. http://d-nb.info/1022318829/34.
Повний текст джерелаYin, Guanchao [Verfasser], Martina [Akademischer Betreuer] Schmid, Walter [Akademischer Betreuer] Reimers, and John [Akademischer Betreuer] Banhart. "Preparation of ultra-thin CuIn1-xGaxSe2 solar cells and their light absorption enhancement / Guanchao Yin. Gutachter: John Banhart ; Walter Reimers ; Martina Schmid. Betreuer: Martina Schmid ; Walter Reimers." Berlin : Technische Universität Berlin, 2015. http://d-nb.info/107524921X/34.
Повний текст джерелаHassan, Safaa. "Optical Property Study of 2D Graded Photonic Super-Crystals for Photon Management." Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1703318/.
Повний текст джерелаSchünemann, Christoph. "Organic Small Molecules: Correlation between Molecular Structure, Thin Film Growth, and Solar Cell Performance." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-105169.
Повний текст джерелаThe aim of this thesis is to demonstrate correlations between the molecular structure of small organic molecules, their arrangement in thin films, and the solar cell performance. For structure analysis of the organic thin films, the combination of variable angle spectroscopic ellipsometry (VASE) and grazing incidence X-ray diffraction (GIXRD) as complementary methods turned out to be a powerful combination. Using both methods, it is possible to obtain information about the crystallinity, crystallite size, intermolecular arrangement, mean molecular orientation, optical constants n and k, and phase separation within thin films. In addition, the topography of thin films is analyzed by atomic force microscopy. First, the thin film morphology of pristine zinc-phthalocyanine (ZnPc) films deposited at different substrate temperatures (Tsub=30°C, 60°C, 90°C) and for varying film thicknesses (5, 10, 25, 50 nm) is investigated. The ZnPc films grow highly crystalline with an upright standing molecular orientation with respect to the substrate surface for all investigated Tsub and all film thicknesses. In effcient organic solar cells, donor and acceptor molecules are commonly co-deposited to form a blend absorber film. This is usually accompanied by a certain phase separation between donor and acceptor molecules leads to a formation of percolation paths necessary to extract electrons and holes towards the electrodes. For ZnPc:C60 blends the origin of this phase separation process is analyzed by investigating different degrees of phase separation induced by film deposition at different Tsub (30°C, 100°C, 140°C) and for different blend ratios (6:1, ... , 1:6 (vol%)). GIXRD measurements indicate that the preferred crystallization of C60 is the driving force for good phase separation. Solar cells with improved phase separation of ZnPc:C60 blends (Tsub=140°C, 1:1) reveal a better charge carrier extraction and thus enhanced effciencies of 3.0% in comparison to 2.5% for the reference device (Tsub=30°C, 1:1). In the second part, the impact of molecular orientation within the absorber thin films on light harvesting is examined for pristine ZnPc and diindenoperylene (DIP) films. For film deposition on weakly interacting substrates like glass, SiO2, amorphous organic transport films, or C60, the orientation of DIP and ZnPc molecules is found to be upright standing. In contrast, GIXRD and VASE measurements show that films deposited onto strongly interacting substrates like Au and Ag, as well as on thin PTCDA templating layers lead to nearly flat-lying ZnPc and DIP molecules. Since the molecular transition dipole moment is oriented in the plane of the DIP and ZnPc molecules, the light absorption in films with flat-lying molecules is strongly improved. Unfortunately, an implementation of Au or Ag sublayers in organic solar cells does not result in reliable dependencies since the enhanced absorption by an improved molecular orientation is superimposed by different effects like microcavity and plasmonic effects. The implementation of PTCDA interlayers leads to transport barriers making the solar cell data interpretation difficult. In the last part, the influence of molecular structure on thin film growth is studied for DIP and its derivatives Ph4-DIP and P4-Ph4-DIP, isoviolanthrone, and Bis-nFl-NTCDI derivatives. GIXRD measurements reveal that steric hindrance is induced by the addition of side chains (for Bis-nFl-NTCDI) and phenyl rings (for Ph4-DIP and P4-Ph4-DIP) (N,N-Bis(fluorene-2-yl)-naphthalenetetra-carboxylic diimide) leading to an amorphous thin film growth. In contrast, DIP films and Bis-HFl-NTCDI films are found to be crystalline. The mean molecular orientation and hence the absorption is strongly affected by the different growth modes of DIP and its derivatives. In OSC, the presence of the phenyl rings prevents an effcient phase separation for (P4-)Ph4-DIP:C60 blends which causes diminished charge extraction in comparison to the crystalline DIP:C60 blends. For the Bis-nFl-NTCDI series, the transport properties are significantly worse in the amorphous films composed of Bis-nFl-NTCDI derivatives with alkyl chains in comparison to the nanocrystalline films made of the bare Bis-HFl-NTCDI
Bessi, Matteo. "DEVELOPMENT OF NEW HIGHLY CONJUGATED MOLECULES AND THEIR APPLICATION IN THE FIELD OF RENEWABLE ENERGY AND BIOMATERIALS." Doctoral thesis, Università di Siena, 2018. http://hdl.handle.net/11365/1066871.
Повний текст джерелаIn recent years hybrid functional materials began to be employed in a series of technologically advanced applications spanning from bio/medical sensors, to renewable energy generation. For this reason, they became the focus of several studies in the field of materials science. At the same time, conjugated molecules have also been intensively investigated, due to the properties arising by the presence of long π-conjugated systems, from the possibility to conduct electricity to the ability to absorb light in a wide range of wavelengths. This PhD work focused on the introduction of such systems in two different kinds of hybrid materials, namely photovoltaic devices for the production of electricity (in particular Dye Sensitzed Solar Cells) and alternative fuels hydrogen), and biocompatible stimuli-responsive hydrogels (capable to conduct electricity and to react upon irradiation), and on the study of their influence on the characteristics of the final material.
Ces dernières années, les matériaux fonctionnels hybrides ont commencé à être employés pour des applications de la haute technologie, allant des senseurs bio/médicaux, à la production d’énergie renouvelable. Pour cette raison, ils sont devenus le centre de plusieurs études dans le domaine des sciences des matériaux. Simultanément, des molécules conjuguées ont été examinée intensément à cause de leurs propriétés venant de leurs longs systèmes π, allant de la possibilité de conduire l’électricité, à leur capacité d’absorber la lumière dans une grande fenêtre spectrale. Le travail de cette thèse se concentre sur l’introduction de tels systèmes dans deux sortes de matériaux hybrides, les dispositifs photovoltaïques pour la production d’électricité (en particuliers les cellules solaires à pigment photosensible) et de carburants alternatifs (hydrogène), et pour les hydrogels biocompatibles sensibles aux stimuli (capables de conduire l’électricité et de réagir sous irradiation), et sur l’étude de leur influence sur les caractéristiques du matériau final.
Pastorelli, Francesco. "Light enhancements in nano-structured solar cells." Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/145638.
Повний текст джерелаEn el presente siglo, algunas de las prioridades son la escasez de la energía y la contaminación. Este trabajo describirá brevemente estos problemas y propondrá un plan de acción que combina el ahorro energético con diferentes fuentes sostenibles de energía. Dentro de estas fuentes de energía renovables, la energía solar es la más abundante. Con el objetivo de hacer la tecnología solar más sostenible y eficiente económicamente nos concentramos en aumentar las características ópticas en celdas solares de película delgada. Dentro de esta categoría, las celdas solares orgánicas son una buena opción porque su desarrollo requiere bajas cantidades de materiales y su fabricación es de baja energía embebida. Adicionalmente, esta tecnología puede ser liviana, transparente, flexible mecánicamente y modular para ser aplicada e integrada en varias soluciones arquitectónicas y de electrónica de consumo. Luego de estudiar los procesos físicos en tales dispositivos y de determinar las metodologías para aumentar ópticamente sus desempeños, mostraremos algunos ejemplos donde teórica y experimentalmente se colecta la radiación solar mediante antenas ópticas. Se reporta por primera vez, una antena de nanogap que acopla eficientemente la luz en la capa activa de la celda solar. Finalmente, se desarrolla el concepto de tecnología fotovoltaica integrada en edificaciones tras introducir algunos ejemplos de fachadas solares. Basados en nuestra investigación, fue posible diseñar y fabricar una celda solar orgánica transparente cuya transparencia en el rango visible estuvo por encima del 20% y una eficiencia de conversión foton-electron aumentada ópticamente que resulto notoriamente similar a la celda solar orgánica opaca equivalente.
La rareté grandissante des ressources en énergie associée à une augmentation de la pollution font partie des enjeux plus importants de ce siècle. Cette thèse décrira brièvement ces deux problématiques et proposera un plan d’action combinant économie d’énergie et diversité des sources d’énergies renouvelables. Parmi les formes d’énergies renouvelables disponibles, l’énergie solaire est la plus abondante. Pour faire de l’énergie solaire une ressource plus durable et plus rentable économiquement, nous proposons d’amplifier les propriétés optiques de cellules solaires en couches minces. Dans cette catégorie, les cellules solaires organiques représentent un choix pertinent de part la faible quantité de matériau nécessaire ainsi que la faible énergie nécessaire au procédé de fabrication. Cette technologie peut être légère, transparente et flexible de sorte qu’elle peut être utilisée dans différentes solutions architecturales s’adaptant à des produits électroniques pour le grand publique. Suivra la théorie sous jacente à ces dispositifs et l’explication de la manière dont leurs performances sont améliorées. Nous présenterons quelques exemples où l’on collecte la radiation solaire avec une antenne optique. Ainsi, nous faisons la toute première démonstration d’une antenne auto-assemblée qui couple efficacement la lumière dans le matériau constituant la couche mince que nous utilisons. Finalement, nous développons le concept de cellules photovoltaïques intégrées en présentant différents cas de façades solaires. Ces travaux nous ont permis de concevoir et de fabriquer une cellule solaire organique transparente avec une transparence dans le visible de 20% et une efficacité de conversion photon-électron améliorée, similaire à une cellule équivalente opaque.
La difficile reperibilità di risorse energetiche e l’inquinamento sono alcuni dei problemi più importanti di questo secolo. In questo lavoro saranno presentati brevemente questi temi proponendo un piano d’azione che abbini il risparmio energetico alle differenti fonti di energia rinnovabili. Nell’insieme delle fonti energetiche rinnovabili l’energia solare è senz’altro la più abbondante. Con l’obbiettivo di rendere lo sfruttamento di tale energia più sostenibile ed economicamente vantaggioso, ci premuriamo di migliorare le caratteristiche ottiche di celle fotovoltaiche a film sottile. In questa categoria utilizziamo, tra le diverse opzioni, le celle solari organiche in quanto la loro fabbricazione richiede una quantità di materiale minimo e un basso consumo energetico. Inoltre questi tipi di dispositivi possono essere leggeri, trasparenti, flessibili e conformabili alle superfici su cui sono applicati. Questa è una tecnologia che potrebbe essere implementata e integrata in varie soluzioni architettoniche o nell’ elettronica di consumo. Dopo aver presentato i principi fisici di tali dispositivi e determinato le metodologie ottiche per aumentarne le prestazioni, vengono illustrati alcuni esempi dove, teoricamente e sperimentalmente, riusciamo a intercettare la radiazione solare con antenne ottiche. Riportiamo, per la prima volta in letteratura, un’antenna ottica con nano-gap che accoppia efficacemente la luce solare nel nostro materiale attivo a film sottile. Nell’ultima parte sviluppiamo il concetto di tecnologia solare integrata negli edifici, introducendo alcuni esempi di facciate solari. Basando il design sulla nostra ricerca, è possibile realizzare una cella solare fotovoltaica organica trasparente, con una trasparenza superiore del 20% e un’ efficienza di conversione fotone-elettrone migliorata grazie all’ottica, che risulta molto vicina all’ equivalente cella fotovoltaica organica non trasparente.
Mariano, Juste Marina. "Light harvesting in fiber array organic solar cells." Doctoral thesis, Universitat Politècnica de Catalunya, 2014. http://hdl.handle.net/10803/284206.
Повний текст джерелаSi considerem que la font d'energia renovable més a abundant és el Sol, la tecnologia fotovoltaica posseeix un dels potencials més alts per poder produir l'energia mundial de forma sostenible i benigne amb el medi ambient. Actualment la majoria dels mòduls comercials estan fabricats de silici cristal.lí ja que aquest material té una gran eficiència. Per tal de rebaixar els costos de producció i incrementar la funcionalitat d'aquest panells solars, diverses tecnologies de capa prima s'estan desenvolupant. Entre elles, la tecnologia fotovoltaica amb materials orgànics ha creat grans expectatives gràcies a les seves propietats intrínseques, com per exemple la seva lleugeresa, flexibilitat o bé semi transparència. Per altra banda, la baixa mobilitat de les càrregues en la majoria dels semiconductors orgànics impedeix l'ús de capes actives no molt més gruixudes que uns pocs nanòmetres. Això provoca que tinguin una capacitat de col.lecció lumínica limitada i com a conseqüència, la eficiència de conversió energètica també ho és. S'han considerat diferents estratègies òptiques per tal de millorar l'absorció en les cel.les solars orgàniques i incrementar la seva eficiència. En aquesta tesi proposem una configuració innovadora basada en l'ús d'una matriu de fibres, les quals atrapen i acoblen la llum en la capa activa per millorar l'absorció d'aquesta. La present tesi consta de cinc capítols. Després d'un capítol introductori, en el capítol 2 s'estudia teòricament l'absorció de llum d'una cel·la solar orgànica dipositada en la part posterior de la matriu de fibres. Per diàmetres de fibra petits, les millores són degudes a l'acoblament d'uns modes recirculants de llum de baixa qualitat. Mentre que per diàmetres grans, la llum sembla estar atrapada de forma efectiva dins de l'estructura formada per les fibres. En els capítols 3 i 4 hem considerat el recobriment per immersió, aquesta tècnica de fabricació pot ser aplicada per dipositar capes des d'una solució precursora a un substrat, independentment de la seva forma. La validesa de la tècnica es demostra quan s'aplica a diferents arquitectures de cel·la. El dipòsit en aquestes estructures no planes de la resta de les capes que formen la cel·la solar orgànica també s'ha investigat. Per exemple, es discuteixen varis canvis rellevants, els quals s'han tingut que introduir per la polvorització catòdica del ITO, per tal d'obtenir elèctrodes transparents amb unes qualitats òptiques i elèctriques òptimes.
Fisher, Brett. "Nanoscale light manipulation for improved organic solar cells." Thesis, University of Surrey, 2017. http://epubs.surrey.ac.uk/844680/.
Повний текст джерелаRaciti, Rosario. "Quantum confinement effects on light absorption in Germanium for solar energy conversion." Doctoral thesis, Università di Catania, 2017. http://hdl.handle.net/10761/3689.
Повний текст джерелаHeinrichová, Patricie. "Fotogenerace náboje v organických polovodičích." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2015. http://www.nusl.cz/ntk/nusl-233406.
Повний текст джерелаHan, Lu. "Synthesis of a Fullerene Acceptor with Visible Absorption for Polymer Solar Cells." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1399248320.
Повний текст джерелаHoye, Robert Lianqi Zhao. "Tuning metal oxides for solar cells and light emitting diodes." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708724.
Повний текст джерелаBranham, Matthew S. "Ultrathin crystalline silicon solar cells incorporating advanced light-trapping structures." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/97833.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 105-110).
Solar photovoltaics, which convert the energy potential of photons from the sun directly into electrical power, hold immense promise as a cornerstone of a clean energy future. Yet their cost remains greater than that of conventional energy sources in most markets and a barrier to large-scale adoption. Crystalline silicon modules, with a 90% share of the worldwide photovoltaic market, have witnessed a precipitous drop in price over the last decade. But going forward, further evolutionary cost reduction will be difficult given the significant cost of the silicon wafer alone - roughly 35% of the module. Dramatically reducing the thickness of silicon used to make a solar cell from the current 350 [mu]m could rewrite the economics of photovoltaics. For thin-film crystalline silicon solar cells to deliver the anticipated cost benefits of reduced material requirements, it is essential that they also yield power conversion efficiencies comparable to commercial solar cells. A significant hurdle to realizing elevated efficiency in crystalline silicon films thinner than 20 [mu]m is the loss of current resulting from reduced photon absorption. A range of light management structures have been proposed in the literature to address this issue and many have been demonstrated to provide high absorption across the spectral range relevant to crystalline silicon, but their promise has yet to be realized in an active photovoltaic device. The focus of this thesis is the development of an experimental platform and fabrication process to evaluate the effectiveness of theoretically-designed light-trapping structures in functional photovoltaic devices. The experimental effort yielded 10-pm-thick crystalline silicon solar cells with a peak short-circuit current of 34.5 mA cm-² and power conversion efficiency of 15.7%. The record performance for a crystalline silicon photovoltaic of such thinness is enabled by an advanced light-trapping design incorporating a 2D photonic crystal and a rear dielectric/reflector stack. A parallel line of questioning addressed in this thesis is whether periodic wavelength-scale optical structures are superior to periodic or random structures with geometric-optics-scale features. Through the synthesis of experimental and theoretical evidence, the case is constructed that wavelength-scale light-trapping structures are in fact comparable to conventional random pyramid surface structures for broad-spectrum absorption in silicon solar cells as thin as 5 [mu]m. These results have important implications for the design of cost-effective and manufacturable light-trapping structures for ultrathin crystalline silicon solar cells.
by Matthew S. Branham.
Ph. D.
Gandhi, Keyur. "Enhancement of light coupling to solar cells using plasmonic structures." Thesis, University of Surrey, 2015. http://epubs.surrey.ac.uk/808845/.
Повний текст джерелаSesuraj, Rufina. "Plasmonic mirror for light-trapping in thin film solar cells." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/366663/.
Повний текст джерелаCrudgington, Lee. "High-performance amorphous silicon solar cells with plasmonic light scattering." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/390381/.
Повний текст джерелаLind, Sebastian. "Recombination losses in organic solar cells : Study of recombination losses in organic solar cells by light intensity-dependent measurements." Thesis, Karlstads universitet, Institutionen för ingenjörsvetenskap och fysik (from 2013), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-68584.
Повний текст джерелаTvingstedt, Kristofer. "Light Trapping and Alternative Electrodes for Organic Photovoltaic Devices." Doctoral thesis, Linköpings universitet, Biomolekylär och Organisk Elektronik, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-17229.
Повний текст джерелаKayra, Seda. "Imaging Solar Cells Using Terahertz Waves." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12612920/index.pdf.
Повний текст джерела100>
direction. It is made up of a p-type base and n-type emitter to create p-n junction. Also, it has a Si4N3 AR coating and Al back contacts on it. To compare the THz measurements to that of electrical measurements, some electrical contact measurements were performed on the solar cell under laser illumination. By using these measurements, the energy conversion efficiency and the quantum efficiency of the solar cell were calculated and measured as 3.44 % and 7%, respectively under the 450mW, 808nm illumination on a specific area of the cell. The results that were obtained form the electrical measurements were compared with the THz results. We found that in order to understand the efficiency of the solar cell using THz-TDRS, a more comprehensive study needs to be done where the changes in the reflection of the THz radiation under different excitation powers and different configurations of the system need to be studied.
Abdullah, Abdulmuin Mostafa. "MULTISCALE MODELING OF III-NITRIDE CORE-SHELL SOLAR CELLS." OpenSIUC, 2017. https://opensiuc.lib.siu.edu/dissertations/1327.
Повний текст джерелаMantilla, Pérez Paola. "Multi-junction thin film solar cells for an optimal light harvesting." Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/406044.
Повний текст джерелаLa fotovoltaica de capa delgada engloba un grupo de tecnologías capaces de capturar la luz en tan sólo unos pocos nanómetros de espesor. Su bajo costo de manufactura, flexibilidad y bajo peso, hace a las capas delgadas candidatas ideales para la integración en edificios. En particular, las celdas orgánicas pueden proveer una transparencia de alta calidad similar a las ventanas convencionales irrealizable con tecnologías basadas en Silicio. Sin embargo, para la producción de electricidad a gran escala en donde la eficiencia es, tal vez, el factor determinante, existen nuevas tecnologías como las celdas solares de perovskita que pueden resultar más adecuadas. Al momento de escribir esta tesis, las eficiencias de celdas de perovskita de simple unión casi duplican la de las mejores celdas orgánicas de simple unión. Una limitante de ambas tecnologías, en especial de las celdas orgánicas y en menor medida de las perovskitas, es la baja movilidad de las cargas. Esta, junto a otras desventajas de los absorbentes orgánicos y perovskitas limita su espesor al rango de los 100 a los 130 nm, y entre los 500 a 600 nm, respectivamente. En resumen, el manejo de la luz debe constituir un ingrediente esencial para el diseño de los dispositivos, tal que se consiga un desempeño óptimo en la aplicación para la cual sean considerados. En esta tesis, con el fin de alcanzar un aprovechamiento óptimo de la luz y por ende aumentar el desempeño de las celdas solares de capa delgada, utilizamos dos enfoques. Por un lado, aumentamos el espesor total de material absorbente dentro del dispositivo sin incrementar el espesor de las capas actives individuales y por otro lado, combinamos absorbentes complementarios para cubrir una porción más amplia del espectro solar. Estos enfoques conllevan al doble reto de encontrar la distribución de campo electromagnético óptima dentro de una estructura compleja de multicapas con dos o más capas activas, junto a la implementación de una recolección o recombinación de cargas efectiva por parte de las capas intermedias encargadas de conectar dos subceldas adyacentes. En el caso de las celdas orgánicas, consideramos celdas de multiunión usando el mismo material activo para todas las subceldas. Para implementarlas, se realizan estructuras cuyas capas activas no excedan los 100 nm. También estudiamos configuraciones donde los materiales tienen absorciones complementarias usando perovskitas. En ambos casos, sobretodo en el primero, se requiere un método sistemático para optimizar el aprovechamiento de la luz. Para obtener las configuraciones óptimas empleamos una estrategia de integración inversa junto con un cálculo del campo eléctrico basado en el modelo de matriz de transferencia. Además, desarrollamos nuevas estrategias para optimizar la colección de cargas en las capas de interconexión de las subceldas aplicables a dispositivos tipo tandem, triple, 4-terminales y serie-paralelo.
Haugan, Einar. "Colloidal Crystals as Templates for Light Harvesting Structures in Solar Cells." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-14541.
Повний текст джерелаEisenlohr, Johannes [Verfasser]. "Light Trapping in High-Efficiency Crystalline Silicon Solar Cells / Johannes Eisenlohr." Konstanz : Bibliothek der Universität Konstanz, 2017. http://d-nb.info/1173087656/34.
Повний текст джерелаPayne, David N. R. "The characterization and enhancement of light scattering for thin solar cells." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/369416/.
Повний текст джерелаEinzinger, Markus. "Excitonic spin engineering for solar cells and organic light-emitting diodes." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/128410.
Повний текст джерелаCataloged from PDF of thesis.
Includes bibliographical references (pages 133-147).
The last two decades have seen renewed interest in molecular organic semiconductors. Since these materials support the formation of excitons, their behavior differs considerably from their inorganic counterparts. This gives rise to a variety of novel properties that can be exploited to create entirely new or improve existing optoelectronic devices. In this thesis, we explore excitonic concepts for improving both organic-light emitting diodes (OLEDs) and silicon solar cells. OLEDs are already commercially successful. However they still suffer from several major drawbacks. Multiexcited-state phenomena are believed to be the root cause of challenges like efficiency roll-off and degradation. The development of novel strategies to reduce exciton densities under heavy load is therefore highly desirable.
In this thesis, it is shown that triplet exciton lifetimes of thermally activated delayed fluorescence (TADF) emitter molecules can be manipulated in the solid state by exploiting intermolecular interactions. The external heavy-atom effect of brominated host molecules leads to increased spin-orbit coupling, which in turn enhances intersystem crossing rates in the guest molecule. Shorter triplet exciton lifetimes are observed, while high photoluminescence quantum yields (PLQYs) are maintained and emission spectra are essentially unaltered. A change in the intersystem crossing rate ratio due to increased dielectric constants leads to almost 50% lower triplet exciton densities in the emissive layer in the steady state and results in an improved onset of the PLQY roll-off at high excitation densities. Efficient OLEDs with better roll-off behavior based on these novel hosts are fabricated, demonstrating the suitability of this concept for real-world applications.
In addition, efficient and stable blue emitters for OLEDs are urgently needed for next-generation display and lighting applications. This thesis presents a tunable series of TADF emitter molecules. After pairing the iminodibenzyl donor with the triazine acceptor via a phenylene linker, dihedral angle tuning is employed to regulate the difference between the energy levels of singlet and triplet excited states. Enhanced reverse intersystem crossing rates are observed in response to increased methylation at the phenylene linker. PLQYs of up to 98% are achieved upon doping into a solid-state matrix. When incorporated in devices, the maximum external quantum efficiency is 28.3% for the emitter with the most favorable trade-off between singlet-triplet splitting and fluorescent oscillator strength.
This result highlights the general applicability of dihedral angle tuning, a molecular design strategy that can be used to improve the performance of donor-acceptor type TADF emitters without significantly changing their emission spectra. In contrast, contemporary solar cell technologies are dominated by silicon, an inorganic semiconductor. But when absorbing photons, silicon (like other semiconductors) wastes energy in excess of its bandgap. Reducing these thermalization losses is possible by sensitizing the silicon solar cell using singlet fission, a carrier multiplication phenomenon that occurs only in organic semiconductors. In this process, two triplet excitons are generated from a singlet exciton. In tetracene, those triplet excitons are energetically matched to the silicon bandgap. Transferring triplet excitons to silicon creates additional electron-hole pairs, promising to increase cell efficiencies from the single-junction limit of 29% to as high as 35%.
In this thesis we reduce the thickness of the protective hafnium oxynitride layer at the surface of a silicon solar cell to just eight angstroms, using electric-field-effect passivation to enable the efficient energy transfer of triplet excitons formed in tetracene. The maximum combined yield of the fission in tetracene and the energy transfer to silicon is around 133%. The processes at the interface are investigated using photoluminescent and magnetic field effect experiments, revealing the impact of different interlayer thicknesses. Finally, the thesis presents the first example of a singlet-fission-enhanced silicon solar cell, a breakthrough that establishes the potential of singlet exciton fission to increase the efficiencies of silicon solar cells and reduce the cost of the energy that they generate.
by Markus Einzinger.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science
Zhou, Dayu. "Light-trapping enhancement in thin film solar cells with photonic crystals." [Ames, Iowa : Iowa State University], 2008.
Знайти повний текст джерелаKnott, Andrew N. "3D printing of light trapping structures for dye-sensitised solar cells." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/50058/.
Повний текст джерелаTiong, Vincent Tiing. "Hydrothermal synthesis and characterisation of Cu2ZnSnS4 light absorbers for solar cells." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/78636/1/Vincent%20Tiing_Tiong_Thesis.pdf.
Повний текст джерелаPaudel, Naba Raj. "Stability Issues in Sputtered CdS/CdTe Solar Cells." University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1321639226.
Повний текст джерелаVandamme, Nicolas. "Nanostructured ultrathin GaAs solar cells." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112111/document.
Повний текст джерелаThe thickness reduction of solar cells is motivated by the reduction of production costs and the enhancement of conversion efficiencies. However, for thicknesses below a few hundreds of nanometers, new light trapping strategies are required. We propose to introduce nanophotonics and plasmonics concepts to absorb light on a wide spectral range in ultrathin GaAs layers. We conceive and fabricate multi-resonant structures made of arrays of metal nanostructures. First, we design a super-absorber made of a 25 nm-thick GaAs slab transferred on a back metallic mirror with a top metal nanogrid that can serve as an alternative front electrode. We analyze numerically the resonance mechanisms that result in an average light absorption of 80% over the 450nm-850nm spectral range. The results are validated by the fabrication and characterization of these multi-resonant super-absorbers made of ultrathin GaAs. Second, we use a similar strategy for GaAs solar cells with thicknesses 10 times thinner than record single-junction photovoltaic devices. A silver nanostructured back mirror is used to enhance the absorption efficiency by the excitation of various resonant modes (Fabry-Perot, guided modes,…). It is combined with localized ohmic contacts in order to enhance the absorption efficiency and to optimize the collection of photogenerated carriers. According to numerical calculations, the short-circuit current densities (Jsc) can reach 22.4 mA/cm2 and 26.0 mA/cm2 for absorber thicknesses of t=120 nm and t=220 nm, respectively. We have developed a fabrication process based on nano-imprint lithography and on the transfer of the active layers. Measurements exhibit record short-circuit currents up to 17.5 mA/cm2 (t=120 nm) and 22.8 mA/cm2 (t=220 nm). These results pave the way toward conversion efficiencies above 20% with single junction solar cells made of absorbers thinner than 200 nm
Chen, Hung-Ling. "Ultrathin and nanowire-based GaAs solar cells." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS355/document.
Повний текст джерелаConfining sunlight in a reduced volume of photovoltaic absorber offers new directions for high-efficiency solar cells. This can be achieved using nanophotonic structures for light trapping, or semiconductor nanowires. First, we have designed and fabricated ultrathin (205 nm) GaAs solar cells. Multi-resonant light trapping is achieved with a nanostructured TiO2/Ag back mirror fabricated using nanoimprint lithography, resulting in a high short-circuit current of 24.6 mA/cm². We obtain the record 1 sun efficiency of 19.9%. A detailed loss analysis is carried out and we provide a realistic pathway toward 25% efficiency using only 200 nm-thick GaAs absorber. Second, we investigate the properties of GaAs nanowires grown on Si substrates and we explore their potential as active absorber. High doping is desired in core-shell nanowire solar cells, but the characterization of single nanowires remains challenging. We show that cathodoluminescence (CL) mapping can be used to determine both n-type and p-type doping levels of GaAs with nanometer scale resolution. n-type III-V semiconductor shows characteristic blueshift emission due to the conduction band filling, while p-type semiconductor exhibits redshift emission due to the dominant bandgap narrowing. The generalized Planck’s law is used to fit the whole spectra and allows for quantitative doping assessment. We also use CL polarimetry to determine selectively the properties of wurtzite and zincblende phases of single nanowires. Finally, we demonstrate successful GaAs nanowire solar cells. These works open new perspectives for next-generation photovoltaics
Gresser, Roland. "Azadipyrromethenes as near-infrared absorber materials for organic solar cells." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-78871.
Повний текст джерелаDie organische Photovoltaik hat das Potential eine kostengünstige Solarzellentechnologie zu werden. Ein Ansatz die Effizienz weiter zu steigern besteht darin den aktiven Spektralbereich in den nahen Infrarotbereich zu erweitern. Bisher gibt es jedoch nur wenige geeignete Materialien. In dieser Arbeit werden Verbindungen aus der Materialklasse der Aza-Bodipy und Dibenzo-Aza-Bodipy als Absorbermaterialien für den nahen Infrarotbereich zur Verwendung in organischen Solarzellen untersucht. Neben der Synthese von neuen Thiophen-substituierten Aza-Bodipys wurden Azadiisoindomethine durch die Addition von Grignardverbindungen an Phthalodinitril und anschließender Reduktion mit Formamid dargestellt. Ausgehend von den Azadiisoindomethinen sind neue Bordifluorid, Borbrenzcatechin und Übergangsmetallkomplexe synthetisiert worden. Alle Substanzen sind mit experimentellen und theoretischen Methoden auf ihre optischen und elektrochemischen Eigenschaften hin untersucht worden. Die elektronische Struktur der (Dibenzo-)Aza-Bodipys ist charakterisiert durch periphere Elektronendonoreinheiten um einen zentralen Elektronenakzeptor. Die langwelligste Absorptionsbande kann in beiden Systemen durch Elektronen schiebende Gruppen an den Donoreinheiten bathochrom, auf über 800 nm verschoben werden. Die Ursache liegt in einem stärkeren Einfluss der Substituenten auf das HOMO als auf das LUMO und einem damit einhergehenden stärkeren Anstieg der HOMO-Energie woraus eine verkleinerte HOMO-LUMO Lücke resultiert. Die Dibenzo-Aza-Bodipys zeichnen sich durch eine rotverschobene Absorption gegenüber den (nicht benzannulierten) Aza-Bodipys aus. Jedoch ist der Akzeptor in den Dibenzo-Aza-Bodipys abgeschwächt, so dass die Rotverschiebung durch die selben Substituenten weniger stark ausgeprägt ist und die Energieniveaus tendenziell höher liegen. Die Verbindungen lassen sich thermisch im Vakuum verdampfen. Die für das Verdampfen wichtige thermische Stabilität, kann durch Austausch von Bordifluorid mit Borbrenzcatechol erhöht werden, ohne die optischen und elektronischen Eigenschaften wesentlich zu beeinflussen. Neben der Charakterisierung der molekularen Eigenschaften, sind einige Verbindungen im Dünnfifilm auf ihre elektrischen Eigenschaften und in Solarzellen untersucht worden. Die Ladungsträgerbeweglichkeit liegt bei den gemessenen Verbindungen zwischen 10E-6 und 10E-4 cm2V-1s-1. Durch Berechnung der Ladungstransportparameter auf Basis erhaltener Kristallstrukturen ist eine höhere Beweglichkeit auf eine günstigere Packung und einen geringeren intermolekularen Abstand zurückgeführt worden. Ausgewählte Verbindungen sind als Donormaterialien in organischen Solarzellen charakterisiert worden. Aus Lösungsmittel prozessierte Solarzellen mit Dibenzo-Aza-Bodipys erreichen eine Effifizienz von 1.6 % mit PC61BM, und 2.1 % mit PC71BM als Akzeptor. Der Effizienz limitierende Faktor ist hierbei der niedrige Füllfaktor von ca. 30 %. In vakuumprozessierten Solarzellen mit planarem Dono-Akzeptor-Übergang von Aza-Bodipys und Dibenzo-Aza-Bodipys hat sich gezeigt, dass die erhaltene Spannung mit abnehmender HOMO Energie der Materialien gesteigert wird. Ein geeignetes Dibenzo-Aza-Bodipy Material ist mit einen Beitrag zum Photostrom im nahen Infrarotbereich, von 750 - 950 nm, gezeigt worden
Ottesen, Petter. "Processing and Characterisation of Diatoms for Light Harvesting Materials in Solar Cells." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for materialteknologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16334.
Повний текст джерелаUlbrich, Carolin [Verfasser]. "Spectral and directional dependence of light-trapping in solar cells / Carolin Ulbrich." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2011. http://d-nb.info/1018190570/34.
Повний текст джерелаKwarikunda, Nicholas. "On the characterisation of solar cells using light beam induced current measurements." Thesis, Nelson Mandela Metropolitan University, 2015. http://hdl.handle.net/10948/11147.
Повний текст джерелаWilliams, Jonathan H. T. "Finite element simulations of excitonic solar cells and organic light emitting diodes." Thesis, University of Bath, 2008. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445404.
Повний текст джерелаMartínez-Denegrí, Sánchez Guillermo. "Light harvesting and energy efficiency in perovskite solar cells and their applications." Doctoral thesis, Universitat Politècnica de Catalunya, 2021. http://hdl.handle.net/10803/672666.
Повний текст джерелаLos problemas medioambientales asociados al uso de combustibles convencionales requieren del uso de fuentes de energía renovables, así como de la implementación de diseños eficientemente energéticos para reducir el consumo de energía. La tecnología fotovoltaica puede emplearse para cubrir ambas estrategias convirtiendo no sólo la luz natural, sino también la artificial, en electricidad. De entre las diferentes tecnologías fotovoltaicas emergentes, las perovskitas alcanzan la más alta eficiencia en conversión de potencia, al mismo tiempo que proporcionan una banda de energía prohibida ampliamente ajustable con pérdidas mínimas de tensión de circuito abierto. Además, su fabricación usa materiales abundantemente disponibles, y no requiere necesariamente de procesos a alta temperatura ni de técnicas de deposición en vacío. En esta tesis, mejoramos la colección de luz en celdas de perovskitas, a la vez que abordamos el concepto de eficiencia energética a través de una fabricación optimizada y su integración en estructuras selectivas de luz. Esto es conseguido gracias a la implementación de estrategias ópticas y materiales aplicadas a diseños específicos de celdas solares de perovskita. Los resultados demuestran que tales estrategias proporcionan una colección de luz y un rendimiento fotovoltaico mayor aplicable a dispositivos fabricados a baja temperatura, y permiten el reciclaje de luz en electricidad para aplicaciones fotónicas alternativas. Las técnicas presentadas podrían ser utilizadas en procedimientos futuros para disminuir la cantidad de Pb empleado en celdas solares de perovskita, y para reducir el consumo de energía durante su fabricación y el funcionamiento de otros dispositivos optoelectrónicos. La tesis está organizada en cuatro capítulos. El Capítulo 1 sirve como una introducción, donde la actual situación energética y la tecnología fotovoltaica son analizadas junto a una descripción de la recolección de luz y la eficiencia energética en celdas solares de perovskita. En el Capítulo 2, demostramos el uso de una estructura periódica para propagar luz ergódicamente y así aumentar la absorción de luz en las celdas solares de perovskita, de manera equivalente a lo que se obtendría usando superficies aleatoriamente texturizadas. Esta estructura sirve como herramienta para reducir el contenido de Pb empleado en celdas solares de perovskita, ya que se puede utilizar 30% menos de material para obtener una celda solar con un rendimiento equivalente. En el Capítulo 3, la misma configuración periódica con una estructura de capa fina depositada en su superficie es empleada como guía de luz, la cual es, además, capaz de transmitir luz polarizada. Además, dos celdas de perovskita integradas en sus laterales reciclan la luz no transmitida en electricidad, incrementando la eficiencia energética del proceso óptico, lo cual podría tener futura aplicación en pantallas de cristal líquido. Finalmente, en el Capítulo 4, demostramos la aplicación de una bicapa de nanopartículas hecha de una capa de SnO2 y otra de TiO2 como materiales de tipo n en celdas solares perovskita. Este tipo de dispositivos, basados en procesos a baja temperatura, funcionan mejor que los que integran un único tipo de nanopartículas, especialmente en dispositivos semitransparentes. En tales dispositivos conseguimos un funcionamiento hasta 30% mejor para celdas solares basadas en capas activas extremadamente finas.
Fotònica
D'AMICO, LILIANA. "Light Management Strategies and Nanostructuring Techniques to Improve Efficiency in Solar Cells." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2015. http://hdl.handle.net/2108/202323.
Повний текст джерелаWang, Qiwei. "New functional molecules and polymers for organic light-emitting diodes and solar cells." HKBU Institutional Repository, 2010. http://repository.hkbu.edu.hk/etd_ra/1200.
Повний текст джерелаGrigioni, I. "DEVELOPMENT OF PHOTOCATALYTIC MATERIALS FOR SOLAR LIGHT CONVERSION INTO FUELS." Doctoral thesis, Università degli Studi di Milano, 2015. http://hdl.handle.net/2434/333066.
Повний текст джерелаCao, Zhixiong. "Silver nanoprisms in plasmonic organic solar cells." Thesis, Ecole centrale de Marseille, 2014. http://www.theses.fr/2014ECDM0015/document.
Повний текст джерелаNowadays there has been a strong global demand for renewable and clean energy due to the rapid consumption of non-renewable fossil fuels and the resulting greenhouse effect. One promising solution to harvest clean and renewable energy is to utilize solar cells to convert the energy of sunlight directly into electricity. Compared to their inorganic counterparts, organic solar cells (OSCs) are now of intensive research interest due to advantages such as light weight, flexibility, the compatibility to low-cost manufacturing processes. Despite these advantages, the power conversion efficiency (PCE) of OSCs still has to be improved for large-scale commercialization. OSCs are made of thin film stacks comprising electrodes, electron transporting layer, active polymer layer and hole transporting layer. In this study, we are concerned with PEDOT:PSS layer which is commonly used as a buffer layer between the anodic electrode and the organic photoactive layer of the OSC thin film stack. We incorporated different concentrations of silver nanoprisms (NPSMs) of sub-wavelength dimension into PEDOT:PSS. The purpose is to take advantage of the unique optical properties of Ag MPSMs arisen from localized surface plasmon resonance (LSPR) to enhance the light harvest and the charge generation efficiency by optimizing absorption and scattering of light in OSCs. We found that the key factors controlling the device performance of plasmonic solar cells include not only the optical properties but also the structural and electrical properties of the resulting hybrid PEDOT:PSS-Ag-NPSM-films. On one hand, the addition of Ag NPSMs led to (1) an increased optical absorption; (2) light scattering at high angles which could possibly lead to more efficient light harvest in OSCs. On the other hand, the following results have been found in the hybrid films: (1) the surface roughness was found to be increased due to the formation of Ag agglomerates, leading to increased charge collection efficiency; (2) the global sheet resistance of the hybrid films also increases due to the excess poly(sodium styrenesulphonate) introduced by incompletely purified Ag NPSMs, resulting in lower short circuit current (Jsc); (3) the Ag nanoprisms and their agglomerates at the PEDOT:PSS/photoactive layer interface could act as recombination centers, leading to reductions in shunt resistance, Jsc and open circuit voltage (Voc). In order to partially counteract the disadvantage (2) and (3), by incorporating further purified Ag NPSMs and/or a small amount of glycerol into PEDOT:PSS, the sheet resistance of hybrid PEDOT:PSS-Ag-NPSM-films was reduced to a resistance value comparable to or lower than that of pristine film
Bezuidenhout, Lucian John-Ross. "On the characterisation of photovoltaic device parameters using light beam induced current measurements." Thesis, Nelson Mandela Metropolitan University, 2015. http://hdl.handle.net/10948/d1020282.
Повний текст джерела