Ce travail a pour but de comprendre l’effet de la compensation du dopage sur les performances des cellules photovoltaïques à base de silicium de qualité solaire purifié par voie métallurgique. Après avoir développé la physique des matériaux compensés, l’influence de la compensation a été étudiée à l’échelle de la plaquette. Nous avons mis en évidence une forte réduction non prédite de la mobilité des porteurs. Au contraire, la compensation du dopage s’est avérée bénéfique à la durée de vie volumique. Nous avons précisé les propriétés recombinantes des dopants. L’étude a été transposée à l’échelle de la cellule. Des rendements de 16% ont été obtenus sur des cellules fortement dopées et compensées. La présence de nombreuses associations entre impuretés dopantes et défauts nous a conduits à l’élaboration d’un algorithme permettant de simuler la cinétique de ce type d’association. Enfin, deux techniques innovantes de mesure des teneurs en dopants et en oxygène interstitiel ont été présentées. / This study aims at understanding the influence of the dopant compensation on the performances of solar cells based on solar-grade silicon purified via metallurgical routes. We first detailed the physics of compensated semiconductors. The compensation effects were then studied at the wafer level. We found a sharp unpredicted reduction in carrier mobility at high compensation level. Conversely, the dopant compensation was shown to be very beneficial to the carrier lifetime. We specified the recombination properties of dopants. We then focused on the compensation effects at the solar cell level. We obtained conversion efficiencies of 16% on highly doped and compensated solar cells, revealing the photovoltaic potential of solar-grade silicon. Since numerous association reactions occur between dopants and defects, we built an algorithm in order to simulate the association kinetics of such reactions. Eventually, we presented two innovative characterisation techniques that allow the concentrations of dopants and light elements to be measured.

La réduction des recombinaisons aux surfaces des cellules solaires est un enjeu fondamental pour l'industrie photovoltaïque. La passivation des défauts électriques en surface peut être obtenue par la formation de liaisons chimiques ou par l'apport de charges électriques capables de repousser un type de porteurs. Ces effets peuvent être obtenus grâce à des couches minces fonctionnalisées déposées sur les surfaces des matériaux qui constituent les cellules. Dans le cadre de cette thèse nous avons étudié la passivation de surface du silicium par des couches minces d’Al2O3 déposées par ALD. La caractérisation physique, optique, structurale et chimique des couches déposées a été réalisée. Une optimisation du procédé d’élaboration (nettoyage pré dépôt, paramètres de dépôt et de recuit) de couches d’alumine a été nécessaire pour répondre aux exigences de la réduction de recombinaisons de surface et obtenir des résultats de passivation optimisés. Enfin, différentes briques technologiques nécessaires à l’intégration de ces couches dans l’architecture d’une cellule solaire silicium ont été étudiées et développées. / The reduction of recombination at the surfaces of solar cells is a fundamental challenge for the photovoltaic industry. Passivation of surface electrical defects can be achieved by the formation of chemical bonds or by the supply of electric charges capable of repelling a type of carrier. These effects can be obtained by means of functionalized thin layers deposited on the surfaces of the materials which constitute the cells. In this thesis we studied the surface passivation of silicon by thin layers of Al2O3 deposited by ALD. The physical, optical, structural and chemical characterization of the deposited layers was carried out. An optimization of the preparation process (pre-deposition cleaning, deposition and annealing parameters) of alumina layers was necessary to meet the requirements of reduction of surface recombinations and to obtain optimized passivation results. Finally, various technological bricks necessary for the integration of these layers in the architecture of a silicon solar cell have been studied and developed.

This thesis focuses on the effects of dopant compensation on the electrical properties of crystalline silicon relevant to the operation of solar cells. We show that the control of the net dopant density, which is essential to the fabrication of high-efficiency solar cells, is very challenging in ingots crystallized with silicon feedstock containing both boron and phosphorus such as upgraded metallurgical-grade silicon. This is because of the strong segregation of phosphorus which induces large net dopant density variations along directionally solidified silicon crystals. To overcome this issue, we propose to use gallium co-doping during crystallization, and demonstrate its potential to control the net dopant density along p-type and n-type silicon ingots grown with silicon containing boron and phosphorus. The characteristics of the resulting highly-compensated material are identified to be: a strong impact of incomplete ionization of dopants on the majority carrier density, an important reduction of the mobility compared to theoretical models and a recombination lifetime which is determined by the net dopant density and dominated after long-term illumination by the boron-oxygen recombination centre. To allow accurate modelling of upgraded-metallurgical silicon solar cells, we propose a parameterization of these fundamental properties of compensated silicon. We study the light-induced lifetime degradation in p-type and n-type Si with a wide range of dopant concentrations and compensation levels and show that the boron-oxygen defect is a grown-in complex involving substitutional boron and is rendered electrically active upon injection of carriers through a charge-driven reconfiguration of the defect. Finally, we apply gallium co-doping to the crystallization of upgraded-metallurgical silicon and demonstrate that it allows to significantly increase the tolerance to phosphorus without compromising neither the ingot yield nor the solar cells performance before light-induced degradation.

O trabalho desta dissertação versou sobre avanços em tecnologias de eletrônica impressa de baixo custo. Em particular, aplicamos as técnicas de impressão por serigrafia e por jato de tinta para confeccionar dispositivos eletrônicos e optoeletrônicos. O primeiro dispositivo construído foi resistências impressas por jato de tinta tendo como matérias primas o poli(3,4-etileno dióxido tiofeno) com sulfonato de poliestireno (PEDOT:PSS) e nanopartículas de prata sobre substratos de vidro. Os valores das resistências foram analisados em se variando parâmetros de impressão. Como segundo dispositivo, imprimimos pela técnica de serigrafia sobre vidro e kapton, antenas de cartões de RFIDs (Radio-Frequency Identifications), também com os dois materiais: tinta de prata e PEDOT:PSS. Os RFIDs foram projetados para operar em frequências entre 860 MHz e 960 MHz. A antena de PEDOT:PSS mostrou alcance de 0,45 m, enquanto que a de tinta prata teve alcance de 1,6 m em 860 MHz e de 4 m em 960 MHz. Fabricamos também células eletroquímicas emissoras de luz (Organic Light Emitting Electrochemical Cells - OLECs), no qual substituímos o eletrodo transparente de óxido de índio (ITO), por um feito de PEDOT:PSS, aplicado por serigrafia sobre vidro. A camada ativa da célula luminescente foi feita por uma mistura de óxido de polietileno complexado com sal de lítio e um polímero luminescente derivado de polifluoreno que emite no verde. As curvas características de corrente e luminância em função da voltagem externa aplicada mostrou o bom desempenho das células fabricadas. Finalmente, produzimos células fotovoltaicas orgânicas, em que o eletrodo transparente, também de PEDOT:PSS, foi depositado por serigrafia sobre vidro. A camada ativa nesse caso foi um sistema bifásico feito de poli(3hexiltiofeno) (P3HT) e um éster, o [6,6]-fenil-C61-ácido metil-butírico (PCBM). Esse dispositivo apresentou um Fator de Preenchimento de 0,47 e uma eficiência externa de aproximadamente 2%. / The work developed along this thesis presents advances in printed electronic technologies of low cost. In particular we applied printable serigraphic and Inkjet technologies to produce electronic and optoelectronic devices. First, we produced resistances having poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) and silver paint as active materials, using an Inkjet printer on glass substrate. We made studies of the resistance performance varying some printed parameters. Then, by serigraphy screen printing was printed, on substrates of kapton and glass, an antenna in an Radio-Frequency Identification card (RFID), also from PEDOT:PSS and from silver paint. This RFID was projected to operate in a frequency range from approximately 860 MHz to 960 MHz. The antenna made of PEDOT:PSS operated in a distance of 0.45 m, while that of silver varied from 1.6 m at 860 MHz to 4 m at 960 MHz. In an Organic Light Emitting Electrochemical Cell (OLEC) we applied one of the electrodes, a PEDOT:PSS layer, as a transparent electrode by serigraphy on glass substrate for made to replace of ITO. The active layer was a mixture of a poly(ethylene oxide) complexed with lithium salt and a derivative of polyfluorene that is a green emitter. The characteristic curves of current and luminance against the applied external voltage assured us the good performance of the device. Similar result was obtained with the performance of an organic photovoltaic (OPV), in which the active layer was a biphasic system made by poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), in which the transparent electrode (PEDOT:PSS) was also printed by serigraphy on glass substrate. In this device we obtained a Fill Factor of 0.47 and an external efficiency of almost 2%.

The Intelligent Algorithm is designed for theusing a Battery source. The main function is to automate the Hybrid System through anintelligent Algorithm so that it takes the decision according to the environmental conditionsfor utilizing the Photovoltaic/Solar Energy and in the absence of this, Fuel Cell energy isused. To enhance the performance of the Fuel Cell and Photovoltaic Cell we used batterybank which acts like a buffer and supply the current continuous to the load. To develop the main System whlogic based controller was used. Fuzzy Logic based controller used to develop this system,because they are chosen to be feasible for both controlling the decision process and predictingthe availability of the available energy on the basis of current Photovoltaic and Battery conditions. The Intelligent Algorithm is designed to optimize the performance of the system and to selectthe best available energy source(s) in regard of the input parameters. The enhance function of these Intelligent Controller is to predict the use of available energy resources and turn on thatparticular source for efficient energy utilization. A fuzzy controller was chosen to take thedecisions for the efficient energy utilization from the given resources. The fuzzy logic basedcontroller is designed in the Matlab-Simulink environment. Initially, the fuzzy based ruleswere built. Then MATLAB based simulation system was designed and implemented. Thenthis whole proposed model is simulated and tested for the accuracy of design and performanceof the system.

L´intérêt grandissant pour les bâtiments à haute efficacité énergétique nécessite le développement de nouveaux types d´enveloppe active et multifonctionnelle pouvant couvrir une partie des besoins énergétiques du bâtiment. Les travaux présentés dans cette thèse concernent le développement de capteurs hybrides solaires photovoltaïques thermique pour la production simultanée d´eau chaude sanitaire et d´électricité au sein d´un unique capteur. L’objectif de cette thèse a été dans un premier temps d´analyser la faisabilité et la complexité du concept de capteur hybrides PV-T. Puis, à partir d’un modèle numérique développé spécifiquement pour appuyer la phase de conception du capteur PV-T les raisons expliquant la limitation des performances de tels capteurs ont été analysées, pour enfin proposer différentes solutions innovantes, tant au niveau des cellules solaires que des matériaux du modules PV et du design du capteur final afin d´en augmenter les performances. L´approche développée est par conséquent multi-échelle allant de la prise en compte des phénomènes physiques pris isolément, des propriétés locales des matériaux jusqu’à la mise en œuvre d’un composant et à l´analyse énergétique et exergétique de ses performances dans un environnement numérique dédié au bâtiment. / In the context of greenhouse gas emissions and fossil and fissile resources depletion, solar energy is one of the most promising sources of power. The building sector is one of the biggest energy consumers after the transport and industrial sectors. Therefore, making use of a building’s envelope (façades and roofs) as solar collecting surfaces is a big challenge facing local building needs, specifically in regard to heat, electricity and cooling. However, available surfaces of a building with suitable orientation are always limited, and in many cases a conflict occurs between their use for either heat or electricity production. This is one of the reasons why the concept of a hybrid photovoltaic-thermal (PV-T) collector seems promising. PV-T collectors are multi-energy components that convert solar energy into both electricity and heat. In fact, PV-T collectors make possible the use of the large amount of solar radiation wasted in PV modules as usable heat in a conventional thermal system. Therefore, PV-T collectors represent in principle one of the most efficient ways to use solar energy (co-generation effect). However, such a concept still faces various barriers due to the multidisciplinary knowledge requirements (material, semi-conductors, thermal) and to the complexity of the multiple physical phenomena implied in such concepts.The objective of this PhD work is to carry out a study based on a multi-scale approach that combines both numerical and experimental investigations regarding the feasibility of the concept of hybrid solar collector. The performance of such components is estimated through an appropriate design analysis, and innovative solutions to design an efficient PV-T collector are presented. Based on improved processing methods and improved material properties, an efficient covered PV-T collector has been designed and tested. This collector was made of PV cells connected to the surface of an optimized flat heat exchanger by an improved lamination process and covered on the front side by a static air layer and AR-coated glass pane and on the back side by thermal insulation material. The results showed a significant improvement of both thermal and electrical efficiency in comparison to all previous works on PV-T concepts found in the literature. System simulations were carried out for a hot water system with the software TRNSYS in order to get a clearer statement on the performance of PV-T collectors. The results show that the integration of PV-T collectors can be more advantageous than standard solar components in regard to thermodynamic considerations (energy and exergy) and environmental considerations (CO2 and primary energy saving).

Abstract This thesis presents measuring techniques as well as measured and simulated results with the aim of helping the design of photovoltaic energy harvesting systems. Therefore, cost-effective measurement setups were developed for collecting the amount of irradiation, for both stationary and moving photovoltaic (PV) installations. The impact of the time resolution of solar radiation data on estimating the available solar energy was investigated. For moving PV installations, the dynamics and the rate of changes in the available irradiation were studied in order to analyse the effects on maximum power point tracking (MPPT) algorithms. In addition, possibilities for harvesting PV energy in indoor environments were also investigated. The main contribution of this thesis is the effective testing of PV cells and complete PV panels: instead of measuring the characteristic I-V (Current-Voltage) response under strictly controlled artificial illumination, photovoltaics are simply biased externally. Then, with the help of synchronized thermography (ST), infrared (IR) images of the PV panel self-heating are recorded. In the obtained IR-images, defected areas are seen as cold spots, since they are not biased by the external power supply. From the calculated temperature variations, the size of the defect area can be calculated and, thus, the loss in output power can be estimated. The method is shown to work both with and without glass encapsulation. / Tiivistelmä Tämä työ esittelee mittaustekniikoita ja mitattuja ja simuloituja tuloksia aurinkoenergian keruujärjestelmien suunnittelun avuksi. Työtä varten kehitettiin kustannustehokas mittausjärjestelmä, jonka avulla arvioitiin aurinkoenergian määrää sekä stationaarisen että liikkuvan valokennon tapauksissa. Näiden lisäksi tutkittiin mittaustaajuuden vaikutusta arvioitaessa saatavilla olevan aurinkoenergian määrää. Liikkuvan PV (photovoltaic)-asennuksen avulla tutkittiin saatavilla olevan aurinkoenergian vaihtelun suuruutta ja nopeutta tarkoituksena analysoida näiden vaikutuksia käytettäviin MPPT-algoritmeihin. Tämä lisäksi tutkittiin myös valoenergian keruumahdollisuuksia sisätiloissa. Työn tärkein kontribuutio on valokennojen ja kokonaisten valopaneelien toiminnallisuuden testaamisen tehostaminen. Tyypillisesti PV:n toiminnallisuus varmistetaan tarkasti määritetyssä ympäristössä suoritetun I-V -ominaiskäyrämittauksen avulla. Tämän työn menetelmä on yksinkertaisesti biasoida PV:t ulkoisesti, minkä jälkeen ST (synchronized thermpgraphy) -kuvauksen avulla määritetään PV-paneelien itselämpenemistä kuvaavat infrapunakuvat. Paneelin vioittuneet alueet erottuvat IR-kuvissa kylminä alueina ulkoisen biasoinnin puuttuessa. IR-kuvista havaituista lämpötilavaihteluista on mahdollista määrittää vioittuneen alueen koko ja siten arvioida myös menetettyä lähtötehoa. Kyseisen metodin toimivuus osoitettiin niin lasikoteloiduilla kuin ilman sitä olevilla PV-paneeleilla.

Le présent travail s'articule autour de l'élaboration du matériau binaire In2S3 en couches minces en tant qu'alternative crédible au composé CdS, dans les cellules solaires à base de CuInS2. Nous avons utilisé la technique de dépôt chimique en solution (Chemical Bath Deposition ou CBD) qui est une technique non coûteuse, non toxique et facile à manipuler. Les couches fabriquées sont caractérisées de différents points de vue et à différentes échelles : caractérisations structurale par diffraction de rayons X (DRX), morphologique par Microscopie Electronique à Balayage (MEB), composition chimique par spectroscopie en dispersion d'énergie (EDS), propriétés optiques par spectrophotométrie, et électriques par la méthode du courant thermiquement stimulé (TSC) et par cartographie de courant localisé. L'objectif de ce travail est l'étude systématique des effets du dopage à l'aluminium et à l'étain, et du traitement thermique des films minces de In2S3 déposés sur verre et sur SnO2. Nous avons réalisé tout d'abord par CBD une multicouche d'In2S3 :4%Al formée par trois dépôts successifs sur des substrats verre et SnO2:F. La comparaison des caractéristiques physicochimiques est faite avec la couche non dopée en tant que caractéristiques de référence. L'étude par DRX faite pour différentes concentrations en Al, montre que ce binaire cristallise selon la structure cubique d'orientation préférentielle (400). Une meilleure cristallisation est obtenue pour une concentration en aluminium dans la solution y = [Al]/[In] = 4%. L'analyse optique montre que le gap est direct, il varie de 2,3 à 2,9 eV; la plus large bande optique est obtenue pour y = 4%. C'est une bonne valeur pour l'utilisation du composé β-In2-xAlxS3 comme fenêtre optique dans les dispositifs photovoltaïques. L'étude de l'effet du dopage à l'étain des multicouches d'In2S3, nous a permis de déduire qu'une meilleure cristallinité, une faible rugosité de la morphologie de surface et un gap optique plus proche de l'optimum théorique, sont obtenus pour des films croissants sur le substrat Pyrex avec une concentration d'étain égale à 2‰. L'analyse effectuée par MEB sur la tranche a montré que l'épaisseur moyenne des couches diminue avec l'augmentation de la concentration d'étain. La présence de l'étain, même en très petites quantités induit des changements importants dans le processus de croissance du film. L'étude TSC montre que l'augmentation de la concentration de l'étain au-delà 2 ‰ conduit à une diminution de courant thermiquement stimulé. Le recuit à différentes températures sous azote est appliqué aux couches dopées et non dopées étudiées précédemment. Le traitement thermique sous azote à 400°C provoque une augmentation nette de la taille des cristallites pour pratiquement tous les films minces dopés ou non dopés déposés sur verre ou sur SnO2. L'analyse par diffraction des rayons X a révélé une conversion de la phase cubique (400) à la phase tétragonale (109) pour l'In2S3:4%. Le changement de la forme des cristallites observé par AFM, met également en évidence l'existence d'une autre phase. Les analyses électriques par TSC montrent particulièrement le comportement électrique de type semiconducteur pour les films minces dopés à 4% Al, et recuit à 400°C, ainsi que pour les films minces dopés à l'étain après recuit à 200°C. L'analyse locale du courant de conduction dans la couche de In2S3 fait apparaître des inhomogénéités plus grandes après traitement thermique. Cependant les bons résultats macroscopiques permettent d'envisager sereinement la fabrication de cellules solaires incluant ces couches. / The present work focuses on the development of binary material In2S3 thin films as an alternative to CdS in thin film solar cells based on CuInS2. We used the technique of Chemical Bath Deposition (CBD) as it is non-expensive, non-toxic and easy to handle. Layers produced are characterized at different levels and scales: cristalline structure by X-ray diffraction (XRD), surface morphology by Scanning Electron Microscopy (SEM), chemical composition by energy dispersive spectroscopy (EDS), optical properties by spectrophotometry and electrical conduction by thermally stimulated currents (TSC) and local mapping of currents. The objective of this work is the systematic study of the effects of aluminum or tin doping, and heat treatment of In2S3 thin films deposited on glass and SnO2. We achieved first a multilayer of CBD In2S3:Al(4%) formed by three successive deposits on glass and SnO2 substrates. Comparison of physicochemical characteristics is made with the undoped layer as reference features. The XRD study done for different Al concentrations, shows that In2S3:Al crystallizes in the cubic structure with preferential orientation (400). Better crystallization is obtained for a concentration of aluminum in the solution y = [Al] / [In] = 4%. The analysis shows that the optical gap is direct, it varies from 2.3 to 2.9 eV, the largest optical band is obtained for y = 4%. It is a good value for the use of the compound β-In2-xAlxS3 as optical window in photovoltaic devices. The effect of tin doping in In2S3 multilayers induces a better crystallinity, low roughness of the surface morphology and optical gap closer to the theoretical optimum, obtained for films grown on Pyrex substrate with a tin concentration equal to 2 ‰. Analysis by SEM on the wafer cleaved-edge showed that the average thickness of the layers decreases with increasing the concentration of tin. The presence of tin, even in very small quantities induced significant changes in the growth process of the film. The TSC study shows that increasing concentration of tin beyond 2‰ leads to a reduction of thermally stimulated current.Annealing at different temperatures under nitrogen is applied to doped and undoped layers studied previously. Heat treatment under nitrogen at 400 ° C causes a net increase of crystallite size for virtually all thin films doped or undoped deposited on glass or SnO2. The analysis by XRD showed a conversion of the cubic phase (400) to the tetragonal phase (109) for In2S3:Al(4%). Change the shape of the crystallites observed by AFM, also highlights the existence of another phase. The TSC analyzes show particular electrical behavior close to semiconductor type for the thin films doped with 4% Al and annealed at 400°C, as well as thin films doped with tin after annealing at 200°C. The local analysis of the conduction current in the layer of In2S3 shows inhomogeneities larger after heat treatment. However, good macroscopic results should allow to fabricate promising solar cells incorporating these layers.

This master thesis analyses the existing methods both practically and theoretically used to detect defected surface area in solar cells. Various methods were used but by using an upgraded CMOS camera without IR filter to implement the electroluminescence method, this has proven to have a very crucial impact on the results. Given the overall results and the acquired information, a procedure with a simple parameter can be setup to carry out the measurements. In addition to this a catalog was formed showing the defects occurring in mono and polycrystalline solar cells.

Basic knowledge of photovoltaic energy transformation, devices and materials, used in photovoltaic are summarized in this master's thesis. The main goal of this thesis is orientation in the photovoltaic systems used these days and explain advantages and disadvantages of these systems during the design phase.