Made available in DSpace on 2016-06-02T20:16:51Z (GMT). No. of bitstreams: 1 5339.pdf: 3033412 bytes, checksum: 3e684081236853aacfacccef70bd4635 (MD5) Previous issue date: 2009-10-02 / Financiadora de Estudos e Projetos / Lead titanate zirconate modified with lanthanum, or PLZT, is one the most ferroelectric compounds utilized in electronic devices, due to its versatility and low production costs in comparison with single-crystalline materials. When adequately prepared, this system presents good optical (high optical transmission) properties, in the visible and near infrared range, and can be electro-optically characterized. Recently, in the end of 90 s, it was verified its high potential as host of photoluminescent ions, as the lanthanide (rare-earth) family. The possibility to use its electro-optic properties (due to its ferroelectric characteristics) and its photoluminescent properties (achieved by the doping process) together ,enlarges the range of application of this system. In this way, the electro-optical characterization of doped PLZT ceramics becomes essential, besides the photonic characterization. In this work, the Senarmont compensator method for electro-optical characterization, or dynamic method, was instrumented, and the values of the induced (due to the quadratic electrooptic effect, Kerr) and permanent (due to the linear electro-optic effect, Pockels) birefringence were determined as a function of the temperature, wave-length and electric-field frequency, of the rare-earth (Nd2O3, Ho2O3, Er2O3, Tm2O3 e Yb2O3) doped PLZT, with La/Zr/Ti=9/65/35, ceramics. The results shown a relationship between of the electro-optic (electro-optic coefficients, or birefringence values) and the dielectric, ferroelectric and structural properties (studied in others works) of the ceramics, that were related with the site occupancy and the structural defects due to the aliovalent dopant. It also can be identified two distinct birefringence dependence as a function of the electric field, for the same electro-optic effect (Kerr, or Pockels), identified as a function of the doping process. In the case of electro-optical characterizations in function of the variable frequency, was observed an agreement with the characterization ferroelectric results made in other works in GCFerr, being evidenced the reduction of electro-optical properties with increasing frequency, where if it observed the occurrence of anomalies in the Pockels response with direct influence on the response Kerr. The characterization as a function of wavelength showed the occurrence of two types of behavior depending on the dopant ion used, being one of them the reduction of the values of birefringence with increasing wavelength (the samples pure and doped ions neodymium (Nd) and ytterbium (Yb)), with a tendency to expected behavior in the literature, however, in the second was seen irregular increase birefringence with increase wavelength (for samples doped with ions holmio ( Ho), erbium (Er) and thulium (Tm),not existing relation with to the theoretical models adopted. In relation the characterization as a function of temperature, this was carried through in a temperature interval that understood the characteristic temperatures of systems relaxores (freezing temperature (TF), the maximum dielectric permittivity (TM (e)) and Burns (TB)), except for the sample doped with neodymium ions, whose freezing temperature is below interval worked. By the curve of birefringence (Δn) as a function of temperature was possible to determine the temperature of maximum birefringence for each of the samples, correlated them with each other. Through the curve (d Δn / dt) vs. T was possible to identify a relationship between the maximum variations, positive and negative birefringence with the temperature characteristics TF and TB. / Entre os sistemas ferroelétricos, o sistema titanato zirconato de chumbo modificado com lantânio (PLZT) é um dos mais amplamente utilizados em dispositivos eletrônicos, dada sua versatilidade em aplicações e relação de custo quando comparado aos materiais monocristalinos utilizados nessa mesma área. Quando preparado pelo devido método de síntese, apresenta excelentes propriedades óticas (altos valores de transmissão ótica) desde a região do visível ao infravermelho próximo, possibilitando uma adequada caracterização de suas propriedades óticas e eletro-óticas. Recentemente, a partir do final da década de 90, foi verificada sua alta potencialidade como matriz hospedeira para íons fotoluminescentes, como os da família dos lantanídeos (ou terras-raras). A possibilidade do uso conjunto das propriedades eletro-óticas (dado seu caráter ferroelétrico) e de suas propriedades luminescentes (devido à incorporação de dopantes laser-ativos) aumentou ainda mais a possibilidade de aplicação desses materiais. Desse modo, a caracterização eletro-ótica das cerâmicas de PLZT dopado torna-se indispensável, além de sua caracterização fotônica. Sendo assim, neste trabalho foi instrumentado um sistema de caracterização eletro-ótica, utilizando o método do compensador Senarmont, também conhecido como método dinâmico, para determinar os valores da birrefringência induzida (devido ao efeito eletro-ótico quadrático, Kerr) e a permanente (devido ao efeito eletro-ótico linear, Pockels) em função da temperatura, comprimento de onda e frequência do campo elétrico de prova para composições cerâmicas de PLZT na razão La/Zr/Ti=9/65/35, dopadas com os óxidos terras-raras Nd2O3, Ho2O3, Er2O3, Tm2O3 e Yb2O3, na quantidade de 1,0% em peso. Os resultados mostraram que há uma relação entre as propriedades eletro-óticas encontradas (seja na forma de valores dos coeficientes eletro-óticos, ou na variação da birrefringência) com as propriedades dielétricas, ferroelétricas e estruturais (já observadas em outros trabalhos do grupo de pesquisa no qual esta dissertação foi realizada) das cerâmicas que, por sua vez, foram relacionadas com o tipo de ocupação e de defeitos gerados devido à incorporação dos dopantes. Além disso, foi possível observar que para uma mesma composição pode ocorrer a presença dos dois tipos de efeitos eletro-óticos - Kerr e Pockels - com proporções distintas em função do tipo de dopante. Através desse método, para esse conjunto de amostras, também foi possível identificar dois tipos distintos de variações da birrefringência em função do campo elétrico para um mesmo efeito eletro-ótico (Kerr, ou Pockels), que também puderam ser associados com o tipo de ocupação dos dopantes. Em se tratando das caracterizações eletro-óticas em função da variável frequência, foi observada uma concordância com os resultados da caracterização ferroelétrica, realizada em outros trabalhos no GCFErr, sendo evidenciada a redução das propriedades eletro-óticas com o aumento da frequência, em que se observou a ocorrência de anomalias na resposta Pockels com influência direta na resposta Kerr. A caracterização como uma função do comprimento de onda mostrou a ocorrência de dois tipos de comportamentos, dependendo do íon dopante utilizado, sendo um deles a redução dos valores da birrefringência com o aumento do comprimento de onda (caso das amostras pura e dopadas com os íons neodímio (Nd) e itérbio (Yb)), havendo certa tendência ao comportamento previsto em literatura, no entanto, no segundo caso foi constatado o aumento irregular da birrefringência com o aumento do comprimento de onda (caso das amostras dopadas com os íons holmio (Ho), érbio (Er) e túlio (Tm), não havendo relação com os modelos teóricos adotados. Quanto à caracterização em função da temperatura, esta foi realizada em um range de que compreendeu as temperaturas características de sistemas relaxores (de freezing (TF(e)), máxima permissividade dielétrica (TM(e)) e Burns (TB(e))), exceto para a amostra dopada com o íon neodímio, cuja TF(e) estava abaixo do intervalo considerado. Através da curva de birrefringência (Δn) em função da temperatura foi possível determinar a temperatura de máxima birrefringência para cada uma das amostras, correlacionado-as entre si. Através da curva de (dΔn/dt) vs. T, foi possível constatar uma relação entre as máximas variações, positiva e negativa, da birrefringência com as temperaturas características TF e TB.

Owing to their versatile orbital character with both local and highly dispersive degrees of freedom, transition metal oxides span the range of ionic, covalent and metallic bonding. They exhibit a vast diversity of electronic phenomena such as high dielectric, piezoelectric, pyroelectric, ferroelectric, magnetic, multiferroic, catalytic, redox, and superconductive properties. The nature of these properties arises from sensitive details in the electronic structure, e.g. orbital mixing and orbital hybridization, due to non-stoichiometry, atomic displacements, broken symmetries etc., and their coupling with external perturbations. In the work presented here, these variations of the electronic structure of crystals due to structural and electronic defects have been investigated, exemplarily for the quasi-binary system SrO - SrTiO3 - TiO2. A number of binary and ternary structures have been studied, both experimentally as well as by means of electronic modeling. The applied methods comprise Resonant X-ray Scattering techniques like Diffraction Anomalous Fine Structure, Anisotropy of Anomalous Scattering and X-ray Absorption Fine Structure, and simultaneously extensive electronic calculations by means of Density Functional Theory and Finite Difference Method Near-Edge Structure to gain a thorough physical understanding of the underlying processes, interactions and dynamics. It is analyzed in detail how compositional variations, e.g. manifesting as oxygen vacancies or ordered stacking faults, alter the short-range order and affect the electronic structure, and how the severe changes in mechanical, optical, electrical as well as electrochemical properties evolve. Various symmetry-property relations have been concluded and interpreted on the basis of these modifications in electronic structure for the orbital structure in rutile TiO2, for distorted TiO6 octahedra and related switching mechanisms of the Ti valence, for elasticity and resistivity in strontium titanate, and for surface relaxations in Ruddlesden-Popper phases. Highlights of the thesis include in particular the methodical development regarding Resonant X-Ray Diffraction, such as the first use of partially forbidden reflections to get the complete phase information not only of the tensorial structure factor but of each individual atomic scattering tensor for a whole spectrum of energies, as well as the determination of orbital degrees of freedom and details of the partial local density of states from these tensors. On the material side, the most prominent results are the identification of the migration-induced field-stabilized polar phase and the exergonic redox behavior in SrTiO3 caused by defect migration and defect separation.

The aim of the present work was to develop a detailed picture of the electronic and magnetic properties of a number of interesting transition metal compounds. A number of complementary experimental and theoretical techniques have been applied, special emphasis was given to x-ray spectroscopies. The studies led to a number of results, and the following conclusions can be drawn: The influence of the magnetic ground state (high-spin (FeO) vs. low-spin (FeS2)) with respect to the recorded x-ray spectra was investigated. In particular, by performing RXES on the Fe L edge of the two compounds, very different ratios of La / Lβ integrated intensity for excitation energies close to the L2 edge have been observed. This effect has been explained in terms of the magnetic structure of FeO (high spin), which inhibits Coster-Kronig processes. Special attention has been given to the direct investigation of orbital ordering in a three dimensional CMR manganite, namely La7/8Sr1/8MnO3, by means of x-ray linear dichroism (XLD). We obtained, for the first time, rather strong indications that the coherently distorted Jahn-Teller phase in La7/8Sr1/8MnO3 is accompanied by a predominantly cross type (x2-z2) / (y2-z2) orbital ordering. In addition to manganites the double perovskite Sr2FeMoO6 the combined study by means of x-ray spectroscopies, magnetic measurements and theoretical band structure calculations could resolve some points discussed controversially in the literature. Both, paramagnetic measurements as well as core level spectroscopy of the Fe 2p, Fe 3s and the Mo 3d states suggest a mixed iron valence state involving around 30% Fe3+- Mo5+ and 70% Fe2+ - Mo6+ states in highly ordered Sr2FeMoO6. XPS valence band studies reveal that the Fe 3d states are not extremely localized, and we find evidence that charge transfer between Fe 3d and O 2p states plays an essential role.

<p>A wide range of optoelectronic applications demand semiconductors optimized for purpose.</p> <p>My research focused on data-driven identification of ABX3 Halide perovskite compositions for optimum photovoltaic absorption in solar cells.</p> <p>I trained machine learning models on previously reported datasets of halide perovskite band gaps based on first principles computations performed at different fidelities.</p> <p>Using these, I identified mixtures of candidate constituents at the A, B or X sites of the perovskite supercell which leveraged how mixed perovskite band gaps deviate from the linear interpolations predicted by Vegard's law of mixing to obtain a selection of stable perovskites with band gaps in the ideal range of 1 to 2 eV for visible light spectrum absorption.</p> <p>These models predict the perovskite band gap using the composition and inherent elemental properties as descriptors.</p> <p>This enables accurate, high fidelity prediction and screening of the much larger chemical space from which the data samples were drawn.</p> <p><br></p> <p>I utilized a recently published density functional theory (DFT) dataset of more than 1300 perovskite band gaps from four different levels of theory, added to an experimental perovskite band gap dataset of \textasciitilde{}100 points, to train random forest regression (RFR), Gaussian process regression (GPR), and Sure Independence Screening and Sparsifying Operator (SISSO) regression models, with data fidelity added as one-hot encoded features.</p> <p>I found that RFR yields the best model with a band gap root mean square error of 0.12 eV on the total dataset and 0.15 eV on the experimental points.</p> <p>SISSO provided compound features and functions for direct prediction of band gap, but errors were larger than from RFR and GPR.</p> <p>Additional insights gained from Pearson correlation and Shapley additive explanation (SHAP) analysis of learned descriptors suggest the RFR models performed best because of (a) their focus on identifying and capturing relevant feature interactions and (b) their flexibility to represent nonlinear relationships between such interactions and the band gap.</p> <p>The best model was deployed for predicting experimental band gap of 37785 hypothetical compounds.</p> <p>Based on this, we identified 1251 stable compounds with band gap predicted to be between 1 and 2 eV at experimental accuracy, successfully narrowing the candidates to about 3% of the screened compositions.</p>

Metal halide perovskites have attracted considerable attention as excellent candidates for application in solar cells. Despite their excellent performance, photovoltaic devices based on perovskite absorber’s wide-scale integration into industrial application is limited by their chemical and electrical instabilities. The central topic of this thesis is therefore to investigate thermodynamic aspects of point defects and the conduction mechanisms along with their implications for current–voltage characteristics i.e.,hysteresis in the solar cells. By application of three different methods, impedance spectroscopy, deep level transient spectroscopy and sweep rate dependent current–voltage characteristics as function of temperature, we show that understanding the fundamental aspects of mobile ionic defects in the material as well as the distribution of these defects in the device is essential for improving the stability and the device performance. We show that halide vacancy-interstitial pairs are present in all investigated perovskite compositions and these defects can lead to a significant reduction in the power conversion efficiency of perovskite solar cells. / Metallhalogenid-Perowskite haben erhebliche Aufmerksamkeit als hervorragende Kandidaten für die Anwendung in Solarzellen. Trotz ihrer ausgezeichneten Leistung ist die breite Integration von photovoltaischen Geräten auf der Grundlage von Perowskit-Absorbern in die industrielle Anwendung durch ihre chemische und elektrische Instabilität begrenzt. Das zentrale Thema dieser Arbeit ist daher die Untersuchung der thermodynamischen Aspekte von Punktdefekten und der Leitungsmechanismen sowie deren Auswirkungen auf die Strom-Spannungs-Charakteristik, i.e., die Hysterese in den Solarzellen. Durch die Anwendung von drei verschiedenen Methoden, der Impedanzspektroskopie, der Transientenspektroskopie auf tiefer Ebene und der Sweep-Rate-abhängigen Strom-Spannungs-Charakteristik als Funktion der Temperatur, zeigen wir, dass das Verständnis der grundlegenden Aspekte der mobilen ionischen Defekte im Material sowie der Verteilung dieser Defekte in der Vorrichtung für die Verbesserung der Stabilität und der Leistung der Vorrichtung von wesentlicher Bedeutung ist. Wir zeigen, dass Halogenid-Vakanz-Zwischengitter-Paare in allen untersuchten Perowskit-Zusammensetzungen vorhanden sind und dass diese Defekte zu einer signiőkanten Verringerung der Energieumwandlungseffizienz von Perowskit-Solarzellen führen können.

[FR] Ce travail rapporte une investigation sur l’élaboration et la caractérisation de quelques oxydes transparents conducteurs, en occurrence l’oxyde de zinc (ZnO), l’oxyde de titane (TiO2) et l’oxyde de nickel (NiO). En revanche, une étude d’hétérojonction d’une couche de pérovskite déposée sur une couche de ZnO a été faite. Le spin coating et le spray pyrolyse qui sont des techniques simples et à faible coût ont été utilisées pour réaliser les différents dépôts. Les films obtenus ont été caractérisés par la Diffraction des Rayons X (DRX), la spectroscopie UV- Visible et la Microscopie Electronique à Balayage (MEB). En vue d’améliorer les propriétés de des oxydes élaborés, plusieurs dépôts ont été effectués. Le premier dépôt a permis de comparer leurs différentes propriétés. L’oxyde de zinc a présenté les meilleures propriétés par rapport aux autres. Il a fait preuve d’une bonne transmittance supérieure à 80%, une bande interdite de plus de 3,25 eV et une bonne cristallinité. Un dépôt a été effectué pour étudier l’influence de la concentration de la solution de ZnO sur ses différentes propriétés. Il est ressorti de cette étude que 0,5 M a donné les meilleurs résultats avec une transmittance de plus de 80% dans le visible et une bande interdite de 3,25 eV. Pour le dépôt de l’étude de l’effet du nombre de couches sur les différentes propriétés, quatre échantillons ont été produits (1 couche, 2 couches, 3 couches et 4 couches). L’échantillon à 4 couches a présenté les plus bons résultats. En plus d’avoir une transparence dans le visible de plus 70% et une bande interdite de 3,25 eV, il possède le plus de grains. Les résultats du dopage de l’oxyde de zinc par l’alumine ont montré que ses propriétés s’améliorent avec le dopage. Ainsi, l’échantillon dopé à 10% a donné de bons résultats comparés aux autres. Sa transmittance est plus de 90% et sa bande interdite est de 3,41 eV. Pour tous les dépôts, les résultats de la diffraction des rayons X ont révélé que l’oxyde de zinc présente deux principaux pics caractéristiques correspondant aux plans cristallographiques (002) et (101). Tous les films de ZnO produits sont polycristallins. Les résultats de l’UV-Visible ont montré que les oxydes élaborés ont une transmittance autour de 80% et une large bande interdite qui varie entre 3,20 eV et 3,41 eV. La perception des grains sur les images MEB a confirmé la cristallinité des films. Les pics identifiés du film de TiO2 correspondent aux plans (101) et (004), tous correspondant à la phase anatase tétragonale du TiO2. L'orientation préférentielle des grains est la direction (101). L’analyse de la DRX de NiO a montré que le pic indexé (111) à 37,636° correspond à la structure cubique des nanoparticules de NiO. Les dépôts de pérovskite sur la couche de ZnO en hétérojonction a révélé une bonne adhésion entre les deux couches. Ces dépôts ont permis d’étudier leurs stabilités et d’initier la fabrication d’une cellule solaire. / [ES] En este trabajo se informa de una investigación sobre el desarrollo y la caracterización de una serie de óxidos conductores transparentes, a saber, óxido de zinc (ZnO), óxido de titanio (TiO2) y óxido de níquel (NiO). Por otra parte, se llevó a cabo un estudio de heterounión de una capa de perovskita depositada sobre una capa de ZnO. Para producir los distintos depósitos se utilizaron técnicas sencillas y de bajo coste, como el recubrimiento por centrifugación y el pirólisis por pulverización. Las películas obtenidas se caracterizaron por difracción de rayos X (DRX), espectroscopia UV-Visible y microscopía electrónica de barrido (SEM). Para mejorar las propiedades de los óxidos producidos, se realizaron varios depósitos. El primer depósito se utilizó para comparar sus diferentes propiedades. El óxido de zinc mostró las mejores propiedades en comparación con los demás. Mostró una buena transmitancia de más del 80%, una brecha de banda de más de 3,25 eV y una buena cristalinidad. Se llevó a cabo una deposición para estudiar la influencia de la concentración de la solución de ZnO en sus distintas propiedades. El estudio demostró que 0,5 M daba los mejores resultados, con una transmitancia superior al 80% en el visible y una separación de banda de 3,25 eV. Se fabricaron cuatro muestras (1 capa, 2 capas, 3 capas y 4 capas) para estudiar el efecto del número de capas en las distintas propiedades. La muestra de 4 capas dio los mejores resultados. Además de tener una transparencia visible superior al 70% y un bandgap de 3,25 eV, presentaba la mayor cantidad de granos. Los resultados del dopaje del óxido de zinc con alúmina mostraron que sus propiedades mejoraban con el dopaje. La muestra dopada al 10% dio buenos resultados en comparación con las demás. Su transmitancia era superior al 90% y su brecha de banda era de 3,41 eV. Para todos los depósitos, los resultados de difracción de rayos X revelaron que el óxido de zinc tiene dos picos característicos principales correspondientes a los planos cristalográficos (002) y (101). Todas las películas de ZnO producidas son policristalinas. Los resultados de UV-Visible mostraron que los óxidos producidos tienen una transmitancia de alrededor del 80% y una amplia banda de separación que varía entre 3,20 eV y 3,41 eV. La percepción de los granos en las imágenes SEM confirmó la cristalinidad de las películas. Los picos identificados en la película de TiO2 corresponden a los planos (101) y (004), todos ellos correspondientes a la fase anatasa tetragonal del TiO2. La orientación de grano preferida es en la dirección (101). El análisis XRD del NiO mostró que el pico indexado (111) a 37,636° corresponde a la estructura cúbica de las nanopartículas de NiO. Los depósitos de perovskita sobre la capa de heterounión de ZnO revelaron una buena adherencia entre ambas capas. Estos depósitos permitieron estudiar su estabilidad e iniciar la fabricación de una célula solar. / [CA] Aquest treball informa d'una investigació sobre l'elaboració i caracterització d'alguns òxids conductors transparents, concretament l'òxid de zinc (ZnO), l'òxid de titani (TiO2) i l'òxid de níquel (NiO). D'altra banda, es va fer un estudi d'heterounió d'una capa de perovskita dipositada sobre una capa de ZnO. Per produir els diferents dipòsits es van utilitzar el recobriment per centrifugació i l'esprai de piròlisi, que són tècniques senzilles i de baix cost. Les pel·lícules obtingudes es van caracteritzar per difracció de raigs X (XRD), espectroscòpia UV-Vis i microscòpia electrònica d'escaneig (SEM). Pero tal de millorar les propietats dels òxids elaborats, s'han realitzat diversos dipòsits. El primer dipòsit va permetre comparar les seves diferents propietats. L'òxid de zinc va mostrar les millors propietats en comparació amb els altres. Va a demostrar una bona transmitància superior al 80%, un interval de banda superior a 3,25 eV i una bona cristalinitat. Es va fer un dipòsit per estudiar la influència de la concentració de la solució de ZnO en les seves diferents propietats. D'aquest estudi es va comprovar que 0,5 M va donar els millors resultats amb una transmitància de més del 80% en el visible i un interval de banda de 3,25 eV. Per a la presentació de l'estudi de l'efecte del nombre de capes sobre les diferents propietats, es van produir quatre mostres (1 capa, 2 capes, 3 capes i 4 capes). La mostra de 4 capes va mostrar els millors resultats. A més de tenir una transparència en el visible de més del 70% i un interval de banda de 3,25 eV, és el que té més grans. Els resultats del dopatge d'òxid de zinc amb alúmina van a demostrar que les seves propietats milloren amb el dopatge. Així, la mostra augmentada al 10% va a donar bons resultats en comparació amb les altres. La seva transmitància és superior al 90% i el seu interval de banda és de 3,41 eV. Per a tots els dipòsits, els resultats de la difracció de raigs X van revelar que l'òxid de zinc presenta dos pics característics principals corresponents als plans cristal·logràfics (002) i (101). Totes les pel·lícules de ZnO produïdes són policristalines. Els resultats UV-Vis van mostrar que els òxids elaborats tenen una transmitància al voltant del 80% i una àmplia banda prohibida que varia entre 3,20 eV i 3,41 eV. La percepció dels grans a les imatges SEM va confirmar la cristalinitat de les pel·lícules. Els pics identificats de la pel·lícula de TiO2 corresponen als plans (101) i (004), tots corresponents a la fase anatasa tetragonal de TiO2. L'orientació preferida del gra és la direcció (101). L'anàlisi XRD de NiO va a mostrar que el pic indexat (111) a 37,636 ° correspon a l'estructura cúbica de les nanopartícules de NiO. Els dipòsits de perovskita a la capa de ZnO d'heterounió van revelar una bona adhesió entre les dues capes. Aquests dipòsits van permetre estudiar la seva estabilitat i iniciar la fabricació d'una cèl·lula solar. / [EN] This work reports on an investigation into the elaboration and characterisation of some of transparent conducting oxides, namely zinc oxide (ZnO), titanium oxide (TiO2) and nickel oxide (NiO). On the other hand, a heterojunction study of a perovskite layer deposited on a ZnO layer was carried out. Spin coating and spray pyrolysis, which are simple, low-cost techniques, were used to produce the various deposits. The films obtained were characterised by X-ray Diffraction (XRD), UV-Visible spectroscopy and Scanning Electron Microscopy (SEM). In order to improve the properties of the oxides produced, several deposits were made. The first deposit was used to compare their different properties. Zinc oxide showed the best properties compared with the others. It showed good transmittance of over 80 %, a band gap of over 3.25 eV and good crystallinity. A deposition was carried out to study the influence of the concentration of the ZnO solution on its various properties. The study showed that 0.5 M gave the best results, with a transmittance of over 80 % in the visible and a band gap of 3.25 eV. Four samples were produced (1 layer, 2 layers, 3 layers and 4 layers) to study the effect of the number of layers on the different properties. The 4-layer sample gave the best results. As well as having a visible transparency of over 70 % and a band gap of 3.25 eV, it had the most grains. The results of doping zinc oxide with alumina showed that its properties improved with doping. The 10 % doped sample gave good results compared with the others. Its transmittance was over 90 % and its band gap was 3.41 eV. For all the deposits, the X-ray diffraction results revealed that the zinc oxide has two main characteristic peaks corresponding to the (002) and (101) crystallographic planes. All the ZnO films produced are polycrystalline. The UV-Visible results showed that the oxides produced have a transmittance of around 80 % and a wide band gap varying between 3.20 eV and 3.41 eV. The perception of the grains on the SEM images confirmed the crystallinity of the films. The peaks identified in the TiO2 film correspond to the (101) and (004) planes, all corresponding to the tetragonal anatase phase of TiO2. The preferred grain orientation is in the (101) direction. XRD analysis of NiO showed that the indexed peak (111) at 37.636° corresponds to the cubic structure of NiO nanoparticles. Deposits of perovskite on the heterojunction ZnO layer revealed good adhesion between the two layers. These deposits were used to study their stability and to initiate the manufacture of a solar cell. / Koné, KE. (2023). Élaboration et caractérisation des couches minces d'oxydes conducteurs transparents (TCO) pour les cellules solaires [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/201922