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Ali, Fawad. "Investigation of metal oxides thin films developed by PVD system for perovskite solar cells." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/127139/1/Fawad_Ali_Thesis.pdf.
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This research presents thin film deposition and characterization of metal oxides using industrially viable Physical Vapour Deposition (PVD) techniques. The research examines low temperature processed electron and hole transport metal oxides for high performance and stable perovskite solar cells. The physical, chemical, optical and electronic properties of the films were investigated and their device performance has been evaluated. The performance of the device improved and the materials cost reduced by replacing the expansive organic materials with more stable inorganic metal oxides.
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Fournier, Olivier. "Synthèse par ALD et caractérisation de couches extractrices d'électrons pour application dans les cellules solaires à base de pérovskite." Electronic Thesis or Diss., Université Paris sciences et lettres, 2021. http://www.theses.fr/2021UPSLC025.
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L'intérêt éveillé par les cellules solaires à base de pérovskite dans la communauté photovoltaique (PV) est allé grandissant ces 10 dernières années, dû notamment aux excellentes propriétés opto-électroniques de ces matériaux, à la diversité de leurs applications potentielles et à leur attractivité économique.Cette technologie est attendue sur le marché du PV d'ici 2023, mais certains défis tels que la stabilité des cellules ou le passage à l'échelle industrielle restent à relever afin de garantir son industrialisation.Une stratégie consiste à optimiser les couches extractrices de charge qui doivent garantir une bonne sélectivité vis-à-vis des porteurs de charge et assurer une bonne interface avec la pérovskite.Le dépôt chimique en phase vapeur à flux alternés (Atomic Layer Deposition - ALD) est une méthode de dépôt industrielle permettant la synthèse de nombreux matériaux.Les films minces déposés par ALD sont denses, homogènes, sans piqûres, conformes, et leur épaisseur et leur composition peuvent être contrôlées à l'échelle nanométrique.L'ALD apparait donc comme un candidat idéal pour déposer ces couches extractrices de charge.Cette thèse s'est intéressée au développement et à la caractérisation de divers oxydes par ALD.Le SnO2 et le TiO2 ont été développés à l'Institut Photovoltaïque d'Île-de-France (IPVF) à partir de deux procédés pour chaque matériau.A partir des caractérisations des couches minces obtenues, un procédé a été retenu pour chaque matériau en vue d'une intégration dans un dispositif PV en tant que couches inorganiques extractrices d'électrons.L'intégration d'une couche compacte de TiO2-ALD (15 nm) dans une architecture mésoporeuse a été démontrée, et ses propriétés comparées à la couche compacte standard déposée par pyrolyse d'aérosol.Des efficacités de conversion similaires de 19% ont été montrées, ainsi qu'une meilleure homogénéité engendrant une meilleure reproductibilité des résultats; ce moyen de dépôt est maintenant utilisé pour les cellules de référence à l'IPVF.L'intégration du SnO2-ALD est aussi présentée.Une couche de 10 nm de SnO2 a montré des efficacités moyennes dues à un déficit dans le facteur de forme.L'ajout d'une couche organique a résolu ce problème et a permis d'atteindre des performances de 16%.Enfin, la modification de ZnO-ALD par des dérivés de l'acide phosphonique a été étudiée.L'organisation des molécules à la surface du ZnO, puis leur effet sur la croissance de la pérovskite ont été détaillés, mais les résultats de cellules complètes restent très faiblePerovskite solar cells have sparked a large interest in the photovoltaic community in the last 10 years due to their expedient optoelectrical properties, their vast scope of applications and their economical attractiveness.They are expected to reach the market by 2023, but challenges have to be tackled first, among which upscale and stability issues.To do so, a strategy is to work on the charge transport layers.They need to ensure a high selectivity towards one charge carrier, and have a good interface.Atomic layer deposition is an industrial deposition technique which allows for the synthesis of a large variety of materials.ALD layers are dense, homogeneous, conformal, pinhole-free and their thickness and composition can be controlled at the nano-scale.ALD hence appears as an ideal candidate to deposit the charge extraction layers.This thesis focuses on the development and on the characterization of various oxides by ALD.SnO2 and TiO2 have been developed at the Institut Photovoltaïque d'Île-de-France (IPVF) with two different processes for each material.Their properties in regard of an integration in perovskite solar cells as inorganic electron transport layers have been explored, and one process for each material has been chosen.The advantageous integration of a 15 nm-thick ALD-TiO2 layer has been demonstrated as compact blocking layer in a mesoporous architecture, and compared to a blocking layer deposited by spray pyrolysis.Similar power conversion efficiencies (PCE) up to 19% have been achieved, with a higher homogeneity of the ALD layer leading to a better reproducibility of the results now used in the baseline production at IPVF.The integration of ALD-SnO2 in planar structures is also discussed.The 10 nm-thick layer alone was found to give mediocre efficiencies due to a lack of fill factor.The addition of an organic interlayer solved this issue allowing for PCE up to 16%.Finally an analysis of the interface between ALD-ZnO modified by phosphonic acid derivatives and a perovskite absorber is proposed.The organization of the molecules at the surface of ZnO and their impact on the perovskite have been determined, but the performances of full devices are poor
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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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Lee, Joun. "Biological assembly and synthesis of inorganic nanostructures." Diss., [Riverside, Calif.] : University of California, Riverside, 2009. http://proquest.umi.com/pqdweb?index=0&did=1957320801&SrchMode=2&sid=1&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1269281222&clientId=48051.
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Thesis (Ph. D.)--University of California, Riverside, 2009.Includes abstract. Available via ProQuest Digital Dissertations. Title from first page of PDF file (viewed March 12, 2010). Includes bibliographical references. Also issued in print.
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Pawar, Krantikumar Subhash. "Ab Initio Modeling of an Electron Transport Layer Interface in Hybrid Perovskite Solar Cells." Wright State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=wright1610125331928229.
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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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Cupido, Ian Patrick. "Nitrogen and argon treatment of titanium dioxide nanowire arrays." University of Western Cape, 2021. http://hdl.handle.net/11394/8040.
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>Magister Scientiae - MScTiO2 nanoparticle films are important electron transport layers (ETLs) in photovoltaics such as dye-sensitised, perovskite and polymer hetero-junction solar cells. These films, however, have significant electron trap-sites as a result of the large density of oxygen vacancies present in nano-sized TiO2. These trap-sites cause electron-hole recombination and ultimately lower photon-to-current conversion efficiency of the underlying cell during operation. Doping the TiO2 lattice with low atomic number elements such as nitrogen is a proven method to overcoming the charge transport inefficiency of TiO2 ETLs; another is the use of one-dimensional (1D) nanowires (NWs), instead of nanoparticles.
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Volkov, Anton. "Ionic and electronic transport in electrochemical and polymer based systems." Doctoral thesis, Linköpings universitet, Fysik och elektroteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-135429.
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Electrochemical systems, which rely on coupled phenomena of the chemical change and electricity, have been utilized for development an interface between biological systems and conventional electronics. The development and detailed understanding of the operation mechanism of such interfaces have a great importance to many fields within life science and conventional electronics. Conducting polymer materials are extensively used as a building block in various applications due to their ability to transduce chemical signal to electrical one and vice versa. The mechanism of the coupling between the mass and charge transfer in electrochemical systems, and particularly in conductive polymer based system, is highly complex and depends on various physical and chemical properties of the materials composing the system of interest. The aims of this thesis have been to study electrochemical systems including conductive polymer based systems and provide knowledge for future development of the devices, which can operate with both chemical and electrical signals. Within the thesis, we studied the operation mechanism of ion bipolar junction transistor (IBJT), which have been previously utilized to modulate delivery of charged molecules. We analysed the different operation modes of IBJT and transition between them on the basis of detailed concentration and potential profiles provided by the model. We also performed investigation of capacitive charging in conductive PEDOT:PSS polymer electrode. We demonstrated that capacitive charging of PEDOT:PSS electrode at the cyclic voltammetry, can be understood within a modified Nernst-Planck-Poisson formalism for two phase system in terms of the coupled ion-electron diffusion and migration without invoking the assumption of any redox reactions. Further, we studied electronic structure and optical properties of a self-doped p-type conducting polymer, which can polymerize itself along the stem of the plants. We performed ab initio calculations for this system in undoped, polaron and bipolaron electronic states. Comparison with experimental data confirmed the formation of undoped or bipolaron states in polymer film depending on applied biases. Finally, we performed simulation of the reduction-oxidation reaction at microband array electrodes. We showed that faradaic current density at microband array electrodes increases due to non-linear mass transport on the microscale compared to the corresponding macroscale systems. The studied microband array electrode was used for developing a laccase-based microband biosensor. The biosensor revealed improved analytical performance, and was utilized for in situ phenol detection.
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Sanderson, Douglas Grant. "An investigation of the relationship between the structure and function of the blue copper electron transport protein plastocyanin using thin-layer, steady-state spectroelectro-chemistry /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487262513407884.
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Tambwe, Kevin. "P- and e- type Semiconductor layers optimization for efficient perovskite photovoltaics." University of Western Cape, 2019. http://hdl.handle.net/11394/7414.
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>Magister Scientiae - MScPerovskite solar cells have attracted a tremendous amount of research interest in the scientific community recently, owing to their remarkable performance reaching up to 22% power conversion efficiency (PCE) in merely 6 to 7 years of development. Numerous advantages such as reduced price of raw materials, ease of fabrication and so on, have contributed to their increased popularity.
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Sahu, Gayatri. "Investigating the Electron Transport and Light Scattering Enhancement in Radial Core-Shell Metal-Metal Oxide Novel 3D Nanoarchitectures for Dye Sensitized Solar Cells." ScholarWorks@UNO, 2012. http://scholarworks.uno.edu/td/1478.
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Dye-sensitized solar cells (DSSCs) have attained considerable attention during the last decade because of the potential of becoming a low cost alternative to silicon based solar cells. Electron transport is one of the prominent processes in the cell and it is further a complex process because the transport medium is a mesoporous film. The gaps in the pores are completely filled by an electrolyte with high ionic strength, resulting in electron-ion interactions. Therefore, the electron transport in these so called state-of-the-art systems has a practical limit because of the low electron diffusion coefficient (Dn) in this mesoporous film photoanode. This work focuses on the influence of the advanced core-shell nanoarchitecture geometry on electron transport and also on the influence of electron-ion interactions. In order to achieve the proposed goals, DSSCs based on ordered, highly aligned, 3D radial core-shell Au-TiO2 hybrid nanowire arrays were fabricated, using three different approaches. J-V, IPCE, and EIS characteristics were studied. The efficiency, light scattering and charge transport properties of the core-shell nanowire based devices were compared to TiO2 nanotube as well as TiO2 mesoporous film based DSSCs. The Au nanowires inside the crystalline TiO2 anatase nanoshell provided a direct conduction path from the TiO2 shell to the TCO substrate and improved transport of electrons between the TiO2 and the TCO. The optical effects were studied by IPCE measurement which demonstrated that Au-TiO2 nanowires showed an improved light harvesting efficiency, including at longer wavelengths where the sensitizer has weak absorption. The metal nanostructures could enhance the absorption in DSSCs by either scattering light enabling a longer optical path-length, localized surface plasmon resonance (LSPR) or by near-field coupling between the surface plasmon polariton (SPP) and the dye excited state. Rapid, radial electron collection is of practical significance because it should allow alternate redox shuttles that show relatively fast electron-interception dynamics to be utilized without significant sacrifice of photocurrent. A combination of improved electron transport and enhanced light harvesting capability make Au-TiO2 core-shell nanowire arrays a promising photoanode nanoarchitecture for improving photovoltaic efficiency while minimizing costs by allowing thinner devices that use less material in their construction.
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Madani, Sepideh Sadat. "Investigation of charge transport metal oxides for efficient and stable perovskite solar cells." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/235892/1/Sepideh%2BSadat%2BMadani%2BThesis%282%29.pdf.
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This research investigates various thin-film metal oxides as charge transport layer for improving the performance and stability of perovskite solar cells. Physical Vapor Deposition techniques such as magnetron sputtering, and electron beam evaporation were used to fabricate the metal oxide thin films. The structural, morphological, chemical, optical, electrical, and electronic properties of the films were studied. Solar Cell Capacitance Simulator was employed for investigating the performance of the PSC using the experimental data as input parameters. Results showed that optimized properties of the metal oxide thin films as charge (hole) transport layer have improved the performance of the PSC device.
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Matta, Sri Kasi Venkata Nageswara Rao. "Computational exploration of two-dimensional (2D) materials for solar energy applications." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/134244/1/Sri%20Kasi%20Venkata%20Nageswara%20Rao%20Matta%20Thesis_Redacted.pdf.
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This project is to find innovative and alternate Nano-sized materials for solar energy applications. This include conversion of solar light energy into electricity or generate clean environment friendly fuels by breaking water into Oxygen and Hydrogen. The study has explored material characteristics at electronic level to reveal new properties. These revelations then compared amongst some of the organic and inorganic materials for the intended purpose. Innovative design of new carbon-compounds (termed as carbon Quantum dots) included in the study for use in the new generation Perovskite solar cells for charge transfer.
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Lee, Veronica. "A Combined Theoretical and Experimental Study on Deposition of Solid State Materials." Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1707299/.
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Deposition of solid state materials span a wide variety of methods and often utilize high energy sources such as plasmas and ultra-violet light resulting in a wide variety of characteristics and applications. A fundamental understanding is essential for furthering the applications of these materials which include catalysis, molecular filtration, electronics, sensing devices, and energy storage among others. A combination of experimental and theoretical work is presented here on several materials including 2D silicates on Pd, boron oxide, and vanadium oxynitride. Silicate formation under low energy electron microscopy demonstrate film permeability to oxygen, while ab initio molecular dynamics simulations reveal the possible initial mechanisms associated with the formation of boron oxide films during atomic layer deposition. Lastly, vanadium oxynitrides have shown preferential sputtering of N over O sites and theoretical binding energies serve as a guide for assigning experimental x-ray photoelectron spectra.
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BENZAQUEN, MOISES. "Proprietes optiques et de transport de l'asga et l'inp." Toulouse 3, 1986. http://www.theses.fr/1986TOU30014.
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Etude a tres basse temperature. On verifie la loi de mott dans ces cuches minces. On confirme l'hypothese de la presence d'une bande d'etats localises au milieu de laquelle des etats etendus apparaissent quand la concentration des donneurs augmente suffisamment, donnant une contribution metallique a la conductivite. Le signe de la constante de hall depend de celui des porteurs en regime de conduction par sauts
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Satter, Md Mahbub. "Design and theoretical study of Wurtzite III-N deep ultraviolet edge emitting laser diodes." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53042.
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Designs for deep ultraviolet (DUV) edge emitting laser diodes (LDs) based on the wurtzite III-nitride (III-N) material system are presented. A combination of proprietary and commercial advanced semiconductor LD simulation software is used to study the operation of III-N based DUV LDs theoretically. Critical factors limiting device performance are identified based on an extensive literature survey. A comprehensive design parameter space is investigated thoroughly with the help of advanced scripting capabilities. Several design strategies are proposed to eliminate the critical problems completely or partially.
A DUV LD design is proposed based exclusively on AlInN active layers grown epitaxially on bulk AlN substrates because AlInN offers a promising alternative to AlGaN for the realization of LDs and LEDs operating in the DUV regime. The proposed AlInN-based design also features a tapered electron blocking layer (EBL) instead of a homogeneous one. Tapered EBLs redistribute the interfacial polarization charge volumetrically throughout the entire EBL thickness via compositional grading, and eliminate the parasitic inversion layer charge.
AlGaN based DUV LD designs are explored also because at present, it may be difficult to grow AlInN epitaxially with superior crystalline quality. Polarization charge matching is proposed to improve electron and hole wavefunction overlap within the active region. Although the strategy of polarization charge matching has already been proposed in the literature to enhance performance of visible wavelength LEDs and LDs, the proposed design presents the first demonstration that polarization charge matching is also feasible for DUV LDs operating at sub-300 nm wavelengths.
A lateral current injection (LCI) LD design is proposed featuring polarization-charge-matched barriers and regrown Ohmic contacts to avoid a group of issues related to the highly inefficient p-type doping of wide bandgap III-N materials in vertical injection designs. The proposed design partially decouples the problem of electrical injection from that of optical confinement. Although the idea of an LCI LD design has been proposed in the literature in the 90s to be used as longer wavelength active sources in optoelectronic integrated circuits using GaInAsP/InP and related material systems, the proposed design is the first theoretical demonstration that this concept can be applied to DUV LDs based on III-N material system.
To solve the problem of hole transport in vertical injection designs, a DUV LD design based exclusively on AlGaN material system is presented, featuring an inverse-tapered p-waveguide layer instead of an EBL. Several EBL designs are investigated, and compared with conventionally-tapered EBL design. Through judicious volumetric redistribution of fixed negative polarization charge, inverse tapering may be exploited to achieve nearly flat valence band profiles free from barriers to hole injection into the active region, in contrast to conventional designs. Numerical simulations demonstrate that the inverse tapered strategy is a viable solution for efficient hole injection in vertical injection DUV LDs operating at shorter wavelengths (< 290 nm).
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Thérond, Pierre-Guy. "Etude des propriétés de transport de composés d'actinides." Grenoble 1, 1986. http://www.theses.fr/1986GRE10109.
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Mesures de la conductivite electrique, de la magnetoconductivite et de l'effet hall sur echantillons monocristallins de npas::(2) et pusb::(1-x)te::(x); analyse des variations en fonction de la temperature et du champ magnetique, modes de diffusion dominants. Etude de l'effet d'un champ magnetique intense sur la conductivite de uas et up et attribution des variations observees soit a un changement de structure antiferromagnetique soit a l'anisotropie du tenseur de conductivite par rapport au vecteur de modulation de la structure magnetique
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Liu, Guoduan. "Fabrication and Characterization of Planar-Structure Perovskite Solar Cells." UKnowledge, 2019. https://uknowledge.uky.edu/ece_etds/137.
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Currently organic-inorganic hybrid perovskite solar cells (PSCs) is one kind of promising photovoltaic technology due to low production cost, easy fabrication method and high power conversion efficiency.
Charge transport layers are found to be critical for device performance and stability. A traditional electron transport layer (ETL), such as TiO2 (Titanium dioxide), is not very efficient for charge extraction at the interface. Compared with TiO2, SnO2 (Tin (IV) Oxide) possesses several advantages such as higher mobility and better energy level alignment. In addition, PSCs with planar structure can be processed at lower temperature compared to PSCs with other structures.
In this thesis, planar-structure perovskite solar cells with SnO2 as the electron transport layer are fabricated. The one-step spin-coating method is employed for the fabrication. Several issues are studied such as annealing the samples in ambient air or glovebox, different concentration of solution used for the samples, the impact of using filter for solutions on samples. Finally, a reproducible fabrication procedure for planer-structure perovskite solar cells with an average power conversion efficiency of 16.8%, and a maximum power conversion efficiency of 18.1% is provided.
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Cherradi, Nabih Mohamed. "Propriétés de transport électronique à basse température d'alliages amorphes Au-Si et de multicouches Au/Si." Nancy 1, 1989. http://www.theses.fr/1989NAN10011.
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Étude de l'effet des interférences quantiques qui dominent à basse température les propriétés de transport électronique des systèmes désordonnés. Des alliages amorphes au::(X)SI::(1-X) et des multicouches Au-Si ont été préparées par évaporation sous vide d'or et de silicium
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Hamdoune, Salaheddine. "Relations entre les structures et les propriétés de transport des solutions solides Li(1+x)Ti(2-x)In(x)P(3)O(12)." Grenoble 1, 1986. http://www.theses.fr/1986GRE10088.
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Etude cristallographique par diffraction rx d'electrons de li::(1+x) ti::(2-x) in::(x) p::(3) o::(7) et de li in p::(2) o::(7) afin de permettre une meilleure comprehension des mecanismes de transport de li**(+) dans ces composes. Suivant la concentration en in, les etudes structurales mettent en evidence trois phases differentes dans la solution solide. Les mesures de la conductivite ont montre que la modification des proprietes electriques est associee a l'etablissement d'une structure favorable a une conductivite elevee. C'est pourquoi cinq cristaux de compositions differentes ont ete etudies. Comme application, essai de realisation d'une pile a partir de la phase la plus conductrice : resultats prometteurs
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Mainos, Constantinos. "Etude des transitions mutiphotoniques dans des molécules diatomiques." Paris 13, 1986. http://www.theses.fr/1986PA132001.
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Etude des transitions rovibroniques multiphotoniques de type dipolaire électrique pour des états moleculaires présentant un couplage de hund (a),(b) ou un couplage intermediaire entre (a) et (b), à l'approximation adiabatique pour décrire la vibration et la rotation. Expressions de l'intensité des raies rotationnelles dans le cas d'une polarisation linéaire ou circulaire et pour des photons identiques. Régles de sélection pour la rotation et le couplage ou se trouvent les états moléculaires (initial et final) pour le cas général d'une transition à "n" photons et d'une multiplicité quelconque. Rapport d'intensités polarisationlinéaire / polarisation circulaire. Expérience à 2 photons pour la bande gamma (o,o) de no et comparaison aux valeurs théoriques calculées
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Ruterana, Pierre. "Structure des interfaces, etude par microscopie electronique en transmission, application : materiaux semiconduteurs iii-v et multicouches pour optiques dans le domaine des rayons x mous." Caen, 1987. http://www.theses.fr/1987CAEN2032.
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Nous avons surtout utilise le mode "haute resolution" sur un microscope a 200kv. La resolution obtenue etait de 2. 4 a. La technique de peparation d'echantillons que nous avons mise au point pour l'etude du procede de passivation (si::(3)n::(4)/gaas) nous a permis de caracteriser dans de tres bonnes conditions les multicouches pour rayons x mous et les heterostructures de croissance epitaxiale. Ce travail fut un suivi des procedes en conjugaison avec d'autres techniques de caracterisation. La comparaison des resultats de ces diverses techniques nous a permis d'apprehender la chimie et la physique des interfaces dans les materiaux etudies
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Pellissier, Anne. "Etude structurale et microscopique du système Y/Si." Grenoble INPG, 1989. http://www.theses.fr/1989INPG0031.
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Le siliciure ysi 1,7 en phase hexagonale s'epitaxie sur un support si(iii) avec un accord de maille quasi parfait. La couche resultante (100-200 a) contient des grains de 50 a 100 a. Une forte anisotropie de structure de bandes est revelee par photoemission. Les lacunes si s'ordonnent en trois dimensions. Mesures electriques: comportement de type semi-metallique et faible hauteur de barriere de schottky pour le contact ysi 1,7/si dope n. Si peut se reepitaxier sur une couche de siliciure d'y elle-meme epitaxiee sur un support si(iii). Un echantillon est obtenu, avec toutefois des defauts d'empilement dans la couche si. La fabrication de couches multiples de cette nature est envisageable
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Vergnat, Michel. "Hydrogénation d'alliages semi-conducteurs amorphes : Structure et propriétés électroniques des alliages amorphes hydrogènes SI::(1-X)SN::(X):H." Nancy 1, 1988. http://www.theses.fr/1988NAN10322.
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Les atomes d'hydrogène sont introduits dans les couches durant leur élaboration par évaporation. L'influence des paramètres de préparation est mise en évidence sur les propriétés physiques de couches de SI pur. Les alliages SI::(1-X)SN::(X) et SI::(1-X)SN::(X) : H peuvent être préparés à l'état amorphe dans une large gamme de compositions. Des études de diffraction électronique, de spectrométrie moessbauer et des mesures de densité massique montrent que ces alliages possèdent une structure tétraédrique. Cette méthode a également permis d'élaborer des multicouches SI/SI : H, de l'étain semiconducteur et de l'hydrure de titane
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Gilles, Bruno. "Etude par rayons X rasants des effets de l'implantation de silicium dans le silicium et de fer dans un grenat." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37597890r.
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BENDRAOUI, ABDELLATIF. "Traitements chimiques et thermiques de composes semi-conducteurs iii-v a base de in, ga, as, p en vue d'une reprise d'epitaxie." Clermont-Ferrand 2, 1989. http://www.theses.fr/1989CLF21151.
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L'etat de surface des semiconducteurs iii-v avant la reprise d'epitaxie conditionne les proprietes electroniques et la stabilite des composants realises. Mise en evidence de l'aspect dynamique de stabilisation des composes iii-v a base de in, ga, p et as sous hydrures. Developpement d'une methode originale de stabilisation statique de ces composes a base de chlorures d'in. Analyse des resultats experimentaux et interpretation en utilisant des modeles theoriques bases sur la thermodynamique statistique
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Lin, Shu-Wei, and 林書緯. "Application and Characterization of Organic-Inorganic Hybrid Electron Transport Layer Used for Organic Photovoltaic Device." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/00125799217068940233.
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碩士國立交通大學
工學院加速器光源科技與應用碩士學位學程
102
In this research we present an “Organic-Inorganic Hybrid Electron Transport Layer” to control microstructure and tune energy level of zinc oxide. In the experimental part, we blend polyethylenimine with sol-gel processed zinc oxide and control the concentration of polyethylenimine to modify property of zinc oxide. The small angle X-ray scattering (SAXS) measurements demonstrate decrease of zinc oxide nanoclusters size for better quality of thin film. The ultraviolet photoelectron spectroscopy (UPS) measurements show shift of energy level for better electron-transporting. Using this approach, P3HT:PC61BM solar cell parameters including short circuit current density and fill factor are improved leading to the PCE increase up to 4.6%.
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Guo, Jin-Ting, and 郭晉廷. "Applying solution-processable electron transport layer on all-inorganic perovskite light-emitting diode and process parameters optimizing." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/hs4rn5.
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碩士國立交通大學
影像與生醫光電研究所
107
All-inorganic perovskites such as CsPbX3 (X=Cl, Br, I) are less susceptible to moisture and oxygen than organic-inorganic hybrid perovskites. With such chemical stability and excellent optical properties, e.g. narrow spectral width and adjustable emission wavelength, it has attracted much attention for optoelectronic applications. In this thesis, we focus on the CsPbBr3 light-emitting diode, and try to simplify the fabrication processes–a nearly fully coating processes. More specifically, ZnO nanoparticles dispersed in Propylene glycol methyl ether acetate (PGMEA, obtained from TWNC) were spin-coated on top of the emission layer of CsPbBr3, serving as an electron transport layer. The experimental results show that this method does not damage the CsPbBr3 film surface, thereby improving the survival time of device and reducing current value. Finally, by adjusting the concentration and dispersed solvent of CsPbBr3 and the speed of ZnO nanoparticle spin coating to optimize the fabrication parameters, the devices with the relatively higher external quantum efficiency were obtained.
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"Electron transfer mechanism between cytochrome C and inorganic complexes." Chinese University of Hong Kong, 1988. http://library.cuhk.edu.hk/record=b5885935.
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Li, Cheng-Wei, and 李丞偉. "Modify TiOx electron transport layer of organic solar cells." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/36270723548232476106.
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Siao, Ming-Deng, and 蕭名登. "Surface Electron Accumulation and Electronic Transport in MoS2 Layer Semiconductors." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/8qzu62.
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碩士國立臺灣科技大學
應用科技研究所
105
Surface electron accumulation (SEA) and thickness-dependent electric properties in the molybdenum disulfide (MoS2) two-dimensional (2D) nanostructures have been observed and investigated. The MoS2 nanoflakes fabricated by mechanical exfoliation exhibit several orders of magnitude higher conductivity than their bulk counterparts. The carrier activation energy of nanostructures is lower than that of the bulk counterparts. The transfer length method was used to determine the current transport in MoS2 following a 2D behavior rather than the conventional 3D mode. Scanning tunneling microscopy measurements confirmed the presence of surface electron accumulation (SEA) in this layer material. Notably, the pronounced n-doping characteristic can be easily removed by producing a fresh surface through mechanical exfoliation. Long-term exposure to air can transform the intrinsic fresh surface into a metallic-like surface, indicating that SEA is not inherent. The FET measurement indicates that the MoS2 nanoflakes with fresh surface exhibit higher mobility and lower electron concentration compare to the nanoflakes with non-fresh surface. A more significant surface scattering in the non-fresh MoS2 nanoflakes was proposed.
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HSU, YUAN-HAO, and 許元豪. "Preparation of Perovskite Active Layer and TiO2 Electron Transport Layer Applied for Perovskite Solar Cell." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/r874qr.
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碩士國立雲林科技大學
電子工程系
106
In order to prepare a high quality perovskite active layer while avoiding complex and time-consuming processes, the perovskite active layer is prepared by using one-step spin-coating method. In order to control the completion and amount of the perovskite grains, the toluene dumping time in the one-step spin-coating method is used to prepare the perovskite active layer of perovskite solar cell (PSC). The electron transport layer (ETL) is prepared by using spin-coating method, where the electron transport layer includes both compact layer (CL) and mesoporous layer (ML). The compact layers with different thicknesses are prepared by using different rotational speeds, and the mesoporous layers are prepared by using different TiO2 materials: TiO2 powder P90 (P90) or TiO2 paste T (T). The PSCs are prepared by using these perovskite active layers and electron transport layers, while the performances of PSCs are investigated. In the first part of this study, one-step spin-coating method is used to prepare perovskite active layers by using different toluene dumping time. The result implies that the highest photoelectric conversion efficiency (PCE) of the PSC is 5.29%, in which the perovskite active layer of PSC is prepared with toluene dumping at the fifth second. In the second part of this study, the TiO2 compact layer is prepared with different rotational speeds, and the TiO2 mesoporous layer is prepared by using different TiO2 materials: TiO2 powder P90 (P90) and TiO2 paste T (T). The result implies the thickness of compact layer with a rotational speed of 5000 rpm in 30 seconds is 35 nm, on which a mesoporous layer of TiO2 (T) is stacked as electron transport layer in PSC and the PSC has the best performances, where the open-circuit voltage (Voc) is 0.95 V, the short-circuit current density (Jsc) is 18.45 mA/cm2, the fill factor (F.F.) is 0.42, and the photoelectric conversion efficiency (PCE) is 7.45%.
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Lin, Guan-Hong, and 林冠宏. "Studies on electron and hole transport layer in polymer solar cell." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/60348014300394884579.
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碩士國立清華大學
化學工程學系
98
In recent years, polymer solar cells have become an important issue, because of attention to alternative energy resources. For polymer solar cells, the morphology of active layer and the series resistance both play important roles in designing highly efficient solar cells.Therefore, the influence of these two factors on efficiency of polymer solar cells based on poly(3-hexylthiophene) (P3HT) blended with [6,6]-pheneyl-C61 butyric acid methyl ester (PCBM) as the active layer is investigated in this thesis. In the first part of this thesis, we use thermal annealing and solvent annealing approach to change the active layer morphology. Under the optimal condition, the device efficiency of 3.75 % and 4 % are achieved for thermal annealing and solvent annealing. In the second part of this thesis, a water-soluble polyaniline, sulfonic acid ring substituted polyaniline (SPAN), which is synthesized in our laboratory, is adopted as a hole transport layer in the polymer solar cells.The device efficiency of 3.75 % is achieved which is similar to device with PEDOT：PSS as a hole transport layer (3.9 %), and indicates that SPAN has opportunity to substitute PEDOT：PSS as hole transport layer material in polymer solar cells. In the last part of this thesis, we use water-soluble crown-ether-substituted polyfluorene, poly[9,9’-bis(6’-(((1,4,7,10,13,16)hexaoxacyclooctadecanyl) methoxy)hexyl)fluorene] (PF-18-crown-6) as the electron transport layer for the first time to reduce series resistance in the polymer solar cells. The device efficiency can be promoted from 2.45 % to 2.82 % after insertion of this layer, which indicates PF-18-crown-6 can reduce series resistance of polymer solar cells and enhance the device efficiency.
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Liao, Ying Han, and 廖盈涵. "Tuning TiO2 Electron Transport Layer to Enhance Perovskite Solar Cell Performance." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/mchd6u.
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Hendry, Antony John. "Study of caged metal ions as electron transfer agents." Phd thesis, 1986. http://hdl.handle.net/1885/138790.
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Wang, Hung-Yi, and 王宏毅. "Electron transport and field-effect properties of ferrocene on few-layer MoS2." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/23314607645291693357.
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碩士國立交通大學
電子物理系所
104
In this thesis, we will discuss the changes of electron transport and field-effect behavior when the organometallic compound-ferrocene is adsorbed on the surface of few-layer molybdenum disulfide. We used mechanical exfoliation to make few-layer molybdenum disulfide (MoS2) flakes on silicon substrate, capped with 300-nm thick silicon dioxide layer. The standard electron beam lithography and thermal evaporation were used to deposit source and drain electrodes on few-layer MoS2 flakes. The MoS2 devices were annealed in a high vacuum in order to fix structural defects of MoS2 and to lower the contact resistivity. Two-probe measurement is used to measure the source-drain current voltage (I-V) curve and gate voltage-drain current (〖V_g-I〗_(SD )) curve. An atomic force microscopy was used to measure the topography and the thickness of few-layer MoS2. After the electrical properties of bare MoS2 devices were characterized, the ferrocene molecules were deposited on surface of the MoS2 by using micro tube. The ferrocene deposited MoS2 devices were annealed in a high vacuum to remove the solvent (chloroform). We then compared the electrical properties with that of bare MoS2 devices. The few-layer MoS2 devices are n-type semiconductors at room temperature. When the ferrocene molecules are deposited, the electric dipole of ferrocene gives internal electric fields that decrease electric fields in MoS2 supplied by the back-gate voltage. It results in the increasing of off-state current as more and more ferrocene molecules are adsorbed on the MoS2 surface. On the other hand, the temperature dependent resistance of ferrocene on MoS2 is well described by the theory of two-dimensional (2D) variable range hopping (VRH) transport in the temperature range from 200 to 100 K. The mobility reduces and the characteristic temperature extracted from fitting to the 2D VRH theory increases after ferrocene deposition. These results indicate that the existence of ferrocene introduces a disorder of stray electric fields in few-layer MoS2.
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KimLien, Duong Thi, and 楊氏金蓮. "Perovskite Solar Cell Having AlxZn(1-x)O Nanorod Electron Transport Layer." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/90636757820691475714.
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碩士國立成功大學
材料科學及工程學系
104
In the present work, we have investigated the use of ZnO nanorods (NRs) and Al modified ZnO (AZO) NRs in perovskite solar cell. ZnO NRs were synthesized using chemical bath deposition. The effect of deposition condition on the NR characteristics was studied. Desired NR layers were used for the deposition of perovskite, CH3NH3PbI3, using either a two-step sequential deposition or a one-step deposition technique. The deposition of the perovskite on the NR layer was optimized by examining the morphology, thickness, crystalline structure, optical absorption, and photoluminescence property. Solar cells were fabricated using selected NR and perovskite layers, having either glass or plastic substrates. The resulting cells were evaluated using a sun light simulator and current-voltage measurement. The effects of the characteristics of the NR layers on the cell performance are addressed.
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Hsu, Tao-Wei, and 徐淘韋. "Multiscale Investigation on Electron and Phonon Transport in Organic & Inorganic Nanowire Thermoelectric Chips." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/54635417753728628412.
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碩士國立清華大學
動力機械工程學系
103
The thermoelectric chips can convert heat into electricity and vice versa. So they can be used as power generators, waste heat recovery systems, refrigerators and air conditoners. The nowadays commercial thermoelectric materials are rare and expensive. Therefore, in this thesis we choose common materials like silicon, germanium and conductive polymer as thermoelectric chips in which we use computational quantum mechanics to find their DOS (Density of States) and band structures. BTE (Boltzmann Transport Equation) is then introduced to calculate the electrical properties of the nanostructures, such as Seebeck coefficient, electrical conductivity and electron thermal conductivity. DFPT (Density Functional Perturbation Theory) is used to simulate the phonon DOS and dispersion relation of the semiconductor and conductive polymer nanowires, which can be used to calculate the phonon group velocity, heat capacity and mean free path. Next, we obtain the phonon thermal conductivity of the nanostructures under phonon gas model. After we predict the electrical and thermal properties of the nanowires, we can calculate their figure of merit (ZT). Improved doping poly-p-phenylene (PPP) nanowire is then chosen to design the thermoelectric chip air conditioner because it has the highest ZT. The coefficient of performance (COP) and temperature dynamics of an electric vehicle’s cabin is calculated. The energy losses of power converters we used are minimized under the Euler-Lagrange (EL) framework. In conclusion, novel PPP-based thermoelectric chip air conditioner will be a potential air conditioner candidate for future electric vehicles since it is able to increase mileage and improve climate control.
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Chang, Yan-Ru, and 張雁茹. "Bathocuproine Doped in PCBM as an Electron Transport Layer for Perovskite Photovoltaic Application." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/c789dr.
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碩士國立交通大學
材料科學與工程學系所
106
In this study, we doped different amounts of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (bathocuproine, BCP) in [6,6]phenyl-C61-butyric acid methyl ester (PC61BM) and successfully improved the power conversion efficiency (PCE) of perovskite photovoltaic device. With the incorporation of BCP, we found that it can not only ameliorate the film formation property of PCBM and the interfacial contact but facilitate the charge transport and separation at the interface through effectively passivating the surface trap states of perovskite as well. These physical, optical, morphological, and electronic improvements result in higher open-circuit voltage (Voc), short-circuit current density (Jsc), and fill factor (FF). Therefore, the PCE is improved from 9.4% to 14.3%. The planar-heterojunction structure of the photovoltaic devices having the confugutation ITO/PEDOT:PSS/CH3NH3PbI3-xClx/PC61BM:BCP/Ag. In order to systematically investigate the effect of BCP doping, we use a combination of characterizations, including grazing-incidence small-angle X-ray scattering (GISAXS), atomic force microscopy (AFM), scanning electron microscopy (SEM), photoluminescence (PL) and ultraviolet–visible spectroscopy (UV-vis). We can understand that, as a result, this approach of incorporating small molecule into a fullerene allowed us to effectively tune the morphology of the ETL on the perovskite active layer and resulted in enhanced device efficiency.
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ThanhSon, Bach, and 白青山. "Integration of Reduced Graphene Oxide in Electron Transport Layer of Perovskite Solar Cells." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/jj2epj.
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碩士國立成功大學
材料科學及工程學系
107
The electron transport layer (ETL) plays a crucial role in facilitating electron extraction and inhibiting recombination in perovskite solar cells. Reduced graphene oxide (RGO) is a potential complement to the common ETL material TiO2 thanks to its excellent electrical conductivity and mobility and the suitability for scalable, low-temperature solution-processed deposition. RGO powder is synthesized through microwave-assisted hydrothermal method, and various amounts of o-phenylenediamine (OPD) are added into the precursor to create Nitrogen-doped RGO of different doping levels. The as-synthesized RGO samples characteristics are examined by XRD, XPS and Raman spectroscopy. The perovskite layer of CH3NH3PbI3 is deposited on RGO and TiO2 using a two-step spin coating process, and the as-deposited perovskite characteristics are examined through photoluminescence and UV-Vis spectroscopy. Finally, photovoltaic performance measurements of completed RGO-integrated devices is conducted under illumination of 1 Sun AM 1.5G sunlight simulator.
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Shih-YingHuang and 黃仕穎. "A study of an inorganic CuSCN hole-transport layer in a ZnO nanocomposite ultraviolet photodetector." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/97835288007157587468.
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碩士國立成功大學
微電子工程研究所
104
This thesis employed electroplating technique to deposit an inorganic CuSCN material to replace the conventional PEDOT:PSS and TPD-Si2 organic materials as a hole transport layer for applying to a novel nanocomposite photodetector. To fabricate the photodetector, the CuSCN hole transport layer was covered with a nanocomposite active layer followed by evaporating BCP as a hole block layer, and a sputtered aluminum film as the electrode. The active layer consists of a P-type organic PVK material and a N-type wide band-gap ZnO nanoparticles. When the device under UV illumination and reverse biased condition, the ZnO nanoparticles in the active layer generate electron/hole pairs. The light-generated holes are transported from PVK and CuSCN to the ITO electrode. In the same time, the light-generated electrons are trapped in the ZnO nanoparticles due to lack of a percolation network and the strong quantum confinement effect of the PVK−ZnO NPs composite band structure. The trapped electrons in the ZnO nanocomposite will create a band bending of the polymer which results in a large amount of holes injecting into the device from the top Al contact, thus generates significant amount of additional photo current. The fabricated photodetector can generate a photocurrent of more than two orders of magnitude higher than that of the dark current under a 360 nm 24.9 μW/cm^2 UV illumination, a high UV to visible rejection ratio of 94 times, and high detectivity of 9.12×10^12 Jones. The device’s performance is better than typical conventional inorganic photodetectors. Besides, the nanocomposite device possesses the advantages of flexibility, light weight and lower cost to manufacture. Therefore, the studied UV detector has a great potential to replace the conventional inorganic one for low cost and high performance UV detecting applications.
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Edelman, Kate Rose. "Orgainc/inorganic materials for organic electronics." Thesis, 2010. http://hdl.handle.net/2152/ETD-UT-2010-08-1895.
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Organic and inorganic/organic hybrid material development is essential for the advancement of electronic devices, such as organic light emitting diodes (OLEDs), organic thin film transistors (OTFTs) and fuel cells. These materials are superior to their inorganic counterparts due to the ability to create flexible devices that can be produced on a large scale and at relatively low cost. First, electron-transport materials (n-type semiconductors) are severely lacking for the development of sufficient OTFTs. Metal-interrupted perylene analogues have been developed, in part, to take advantage of the ability to tune the electronic properties of these complexes by simply changing the metal center. Second, fluorescent molecules play an essential role in expansion of microscale sensor systems and OLEDs. Solvent dependent triple fluorescence has been discovered for a series of isobutylnaphthalimide derivatives, which is unique for naphthalimide materials which typically demonstrate dual fluorescence. Next, oxygen reduction electrocatalysts in fuel cells have hindered commercialization due to the high price of platinum. Here, polymer-containing palladium nanoparticles utilize the metal center embedded directly in the polymer backbone to serve as a seed point for metal nanoparticle growth. The palladium nanoparticles within the polymer matrix display significant catalytic activity towards oxygen reduction. Also, poly-9,9-dioctylfluorene is at the forefront of blue-light emitting materials for OLEDs due to high quantum efficiencies and good thermal stability; however, a low-energy green band emission contaminant in devices has hindered application. Oligofluorene synthesis to understand this phenomenon can be difficult thus a boronic acid protection has been implemented before Suzuki-Miyaura coupling occurs to reduce the number of byproducts produced and to accomplish synthesis of oligofluorenes such as a pentamer and heptamer. Lastly, while deviating from organic and inorganic/organic electronic materials, a discussion on the development of a mononuclear Rh(II) complexes, specifically a piano-stool conformation which assists in isolation of this species. The piano-stool ligand structure consists of alkyl chains for easy conformational adjustments when the Rh(I) metal center undergoes oxidation, bulky phosphine groups and an electron-donating arene ring to keep the Rh(II) metal center from dimerization. Most importantly, the research conducted has strived toward advancements over a broad range of scientific investigation.text
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Chang, Chun-Kai, and 張竣凱. "Organic/inorganic Hybrid Light-Emitting Devices by incorporating Tungsten Trioxide Nanorod Arrays as the Electron-Transporting Layer." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/tx72qx.
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碩士國立交通大學
照明與能源光電研究所
106
In this research, we prepared inverted light-emitting devices with improved luminance and current efficiency by combining tungsten trioxide (WO3) nanorod arrays and polyethylenimine ethoxylated (PEIE) buffer layer. Different types of WO3 nanostructures were grown on the indium-tin oxide (ITO) substrates by sol-gel process and hydrothermal method. PEIE buffer layer was introduced between WO3 nanostructures and emissive layer to improve the electron mobility and obtain the longer fluorescence lifetime. The prepared WO3 nanostructures show high transmittance over 90% in the wavelength of 400–700 nm. Inverted devices with the configuration of ITO/WO3 nanostructures/PEIE/poly(2-methoxy-5-(2’-ethylhexyloxy)-1,4-phenylene vinylene)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/WO3 film/Au were constructed and evaluated. The best device based on WO3 NAs with height of 300 nm showed a max brightness of 3,079 cd/m2 and current efficiency of 0.22 cd/A, evealing much higher performance compared with those using WO3 nanostructures or nanorods with longer lengths as electron transporting layers.
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Huang, Hao-Jung, and 黃浩榕. "A Study of High Efficient Organic Electroluminescent Devices with Multi-Layer Electron Transport Structure." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/43437894603157769335.
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碩士國立成功大學
電機工程學系
88
In this thesis, doped electron transport layer (ETL) and doped hole transport layer (HTL) organic electroluminescent (OEL) devices are successfully prepared by a vacuum evaporation system. The optimum rubrene doping concentration in Tris-(8-hydroxyquinolinato) aluminum(Ⅲ) (Alq3) and N,N’-diphenyl-N,N’-bis(3-methyphenyl)-1,1’-biphenyl-4,4’-diamine (TPD), which is 2.5 and 4 wt%, respectively. We have demonstrated that using Li/Al cathode and a Phthalocyanine Copper (CuPc) buffer layer for the device, ITO/CuPc/ TPD/Alq3/CuPc/Li/Al, can efficiently lower the operation voltages and enhance the performance of OEL devices. Furthermore, using CuPc to replace part of Alq3 for electron transport layer can lower operating voltages and get better luminous efficiencies. The role of CuPc in such OEL devices will be discussed. The vacuum evaporation system is adopted to deposit organic films of Alq3, TPD, and CuPc on the ITO coated glass substrate. The highly fluorescent molecule, rubrene, is doped in either Alq3 or TPD. Current-voltage curves are used for electrical analysis. Luminance, photoluminescence (PL), electroluminescence (EL) , ultraviolet-visible spectroscopy (UV-Vis), and commission innternationale de I’Eclairage (CIE) are used for the study of optical characteristics. By using a Li/Al cathode and replacing part of Alq3 with CuPc as an electron transport layer, we can lower the operating voltage and enhance the performance of OEL devices. The luminance, 1000 cd/m2, can be obtained at 5.5 V driving voltage. The maximum luminance is as high as 14000 cd/m2 in the investigation. Finally, We have demonstrated that CuPc is not a good material for an electron transport layer itself, but CuPc with a Li contact can get better electron transport property than Alq3.
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Wang, Tsung-Chang, and 王宗昶. "Investigation of electron transport layer and fluoride for the properties of organic solar cells." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/fu8884.
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碩士國立高雄大學
應用物理學系碩士班
97
The organic solar cells (OSC) have several superior advantages to inorganic solar cells, including lower cost, larger fabrication area, lighter weight and flexible property. Unfortunately, the power conversion efficiency (PCE) of the OSC is quite poor at the present time. Thus, improvement of PCE is an important issue. And then there are improvement methods of OSC from introduction of device concept such as change in active material, light harvesting structure, annealing and the electron transport layer (ETL). In this study, the structure of small-molecule OSC with is ITO-coated glass substrate /Copper phthalocyanine (CuPc) / fullerene (C60)/electron transport layer (ETL)/Al. The active layer is composed of CuPc and C60. 2-(4-Biphenylyl)-5-(4-tert-butylphenyl)-1, 3, 4-oxadiazole (PBD), Aluminum tris(8-hydroxyquinoline) (Alq3) and bathocuproine (BCP) are used as an electron transport layer. The materials of LiF and KF are used as a modification layer. In this study, the thicknesses of each material have been optimized for a better PCE. Besides, the short current density (Jsc) of devices with BCP layer was greatly improved compared with that of other ETL materials. The superior properties of BCP, such as lower electron injection barrier, higher UV/vis absorption efficiency and lower surface roughness, have been demonstrated by the energy level diagram, UV/vis absorption spectra and atom force microscope (AFM) data. In order to further improve the PCE of devices, we add ultra-thin fluoride as a modification layer to the devices with BCP layer. The PCE of OSC is improved from 0.54 % to 0.64 %.
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Shin-YuLin and 林信宇. "Deposition of Gallium Nitride films as electron transport and hole blocking layer in OLED." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/76k2ax.
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碩士國立成功大學
化學工程學系
102
This article is about the research of Gallium Nitride(GaN) as electron injection and hole blocking layer in Organic Light Emitting Diode(OLED). The traditional material for electron injection and hole blocking layer is BCP, which Tg point is low. We want to use GaN to replace Bathocuproine(BCP) to enhance the stability of OLED device. Using RF sputtering method to grow GaN film under different condition, thermal evaporation system to deposit organic layer. In the begin the device performance was bad ,with turn on voltage up to 15V and only 119cd/m2. After figuring out the problem, change the working pressure from 10mTorr to 5mTorr, and treat the surface with N2 plasma. The device performance now enhances from 119cd/m2 to 1091cd/m2.
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Yi-ChingChen and 陳怡靜. "Performance Investigation of Perovskite Solar Cells with Multi-Layer Electron and Hole Transport Structures." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/kjq5rb.
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Tsai, Yung-Han, and 蔡詠涵. "Two-dimensional atomically thin perovskite oxide as electron transport layer for perovskite solar cells." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/as64kv.
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碩士國立臺灣大學
材料科學與工程學研究所
106
Two-dimensional (2D) oxides are a large group of 2D materials. These 2D oxides can be divided into two subgroups: 2D metal oxides and 2D perovskite oxides. They are rich in structural diversity, electronic properties, and have novel physical and chemical properties from quantum confinement or surface effects comparing to their bulk states. 2D oxides are widely applied in the nanocapacitors, secondary batteries, and photocatalysts fields. Among the 2D perovskite oxides, Ca2Nb3O10 (CNO) atomic sheet is an n-type wide bandgap semiconductor. It has well aligned conduction band minimum with that of the lead halide perovskite, which is an efficient light absorber for solar cell application. These properties make CNO a promising electron transport material to extract electrons and block holes from lead halide perovskite light absorber. On the other hand, comparing to the conventional high temperature (> 500 ˚C) sintered compact-TiO2 electron transport layer, CNO can be deposited with relative low temperature (< 150 ˚C) solution process. In this work, we deposited CNO with low temperature Langmuir-Blodgett deposition method as electron transport layer to fabricate perovskite solar cell. The resultant devices showed best efficiency of 14.10%, which is compatible to the conventional high-temperature sintered compact-TiO2 device (14.07%). Moreover, the CNO based devices showed better electron transport ability than the conventional ones. Our work showed that CNO atomic sheet is a highly promising electron transport material for low-temperature solution processed all perovskite structure solar cells.
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Kim, Seyoung 1981. "Electron transport in graphene transistors and heterostructures : towards graphene-based nanoelectronics." Thesis, 2012. http://hdl.handle.net/2152/ETD-UT-2012-05-5420.
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Two graphene layers placed in close proximity offer a unique system to investigate interacting electron physics as well as to test novel electronic device concepts. In this system, the interlayer spacing can be reduced to value much smaller than that achievable in semiconductor heterostructures, and the zero energy band-gap allows the realization of coupled hole-hole, electron-hole, and electron-electron two-dimensional systems in the same sample. Leveraging the fabrication technique and electron transport study in dual-gated graphene field-effect transistors, we realize independently contacted graphene double layers separated by an ultra-thin dielectric. We probe the resistance and density of each layer, and quantitatively explain their dependence on the backgate and interlayer bias. We experimentally measure the Coulomb drag between the two graphene layers for the first time, by flowing current in one layer and measuring the voltage drop in the opposite layer. The drag resistivity gauges the momentum transfer between the two layers, which, in turn, probes the interlayer electron-electron scattering rate. The temperature dependence of the Coulomb drag above temperatures of 50 K reveals that the ground state in each layer is a Fermi liquid. Below 50 K we observe mesoscopic fluctuations of the drag resistivity, as a result of the interplay between coherent intralayer transport and interlayer interaction. In addition, we develop a technique to directly measure the Fermi energy in an electron system as a function of carrier density using double layer structure. We demonstrate this method in the double layer graphene structure and probe the Fermi energy in graphene both at zero and in high magnetic fields. Last, we realize dual-gated bilayer graphene devices, where we investigate quantum Hall effects at zero energy as a function of transverse electric field and perpendicular magnetic field. Here we observe a development of v = 0 quantum Hall state at large electric fields and in high magnetic fields, which is explained by broken spin and valley spin symmetry in the zero energy Landau levels.text
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Agrawal, Neetu. "Electron optics with dirac fermions: electron transport in Mano-and bi- layer graphene through various scalar and vector potential barriers." Thesis, 2013. http://localhost:8080/iit/handle/2074/6561.
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