In 2013, the worldwide production of renewable electricity accounted for 22.1% of the total energy production with 0.9% coming from solar photovoltaics (PVs). Recently, there has been a growing interest for Cu2ZnSnS4 (CZTS) quaternary semiconductor due to the abundance and low cost of its precursors. Moreover, this chalcopyrite material has an ideal direct band gap around 1.5 eV, high absorption coefficient (α >104 cm-1) and high conductivity, making it suitable for nanostructured and dye-sensitized solar cell (DSSC) applications. Here, CZTS nanoparticles have been synthesized by pulsed laser deposition (PLD) and simultaneously deposited in the interstitial space of ZnO nanowire arrays to form bulk heterojunction 3D nanostructured solar cells. Secondly, vertically oriented CZTS nanoplates have been synthesized by PLD and used as counter electrode in platinum-free dye-sensitized solar cells. These CZTS nanostructures proved to be suitable in achieving workable solar cells, which could significantly cut down the cell cost and provide environmentally friendly photovoltaic devices. Alternately, hybrid organic–inorganic perovskite solar cells have become one of the most attractive photovoltaic technologies with easy solution fabrication and high conversion efficiencies. However, the devices remain unstable under certain processing and environmental conditions. Herein, formamidinium lead tri-halide perovskite (FAPbI3) planar heterojunction solar cells have been fabricated under a controlled environment. The fabrication parameters (precursor concentration, annealing, etc) and the effect of humidity on the structural, optical, and electrical properties of FAPbI3 thin films and devices have been investigated and proved to be critical in the processing of efficient devices. Solar cells with conversion efficiency of 16.6% have been obtained. Furthermore, in-situ techniques such as in-situ (scanning) transmission electron microscopy and in-situ XRD were performed to understand the crystallization and degradation mechanisms of FAPbI3 thin films.The in-situ data were correlated with planar heterojunction FAPbI3 devices efficiency data in order to improve the device fabrication process.

Le présent travail porte sur l'élaboration de couches minces du matériau binaire SnS avec des propriétés physico-chimiques répondant le mieux possible aux exigences d'une bonne alternative au composé ternaire CuInS2, dans les cellules solaires. Nous avons utilisé la technique de dépôt chimique en solution (ou Chemical Bath Deposition CBD) qui est une technique peu coûteuse, non toxique et facile à manipuler. Les couches fabriquées sont testées sur le plan cristallographique, chimique, morphologique et optique à différentes échelles, en utilisant les techniques de diffraction des rayons X, de profilométrie, de microscopie électronique à balayage associée à la dispersion en énergie des photons X, de microscopie à force atomique ou électrostatique, et de mesures par spectrophotométrie. Des recuits à différentes températures et des dopages à différentes concentrations sont effectués. Un calcul de l'épaisseur des films minces de SnS, basé sur la méthode des enveloppes des franges d'interférences dans les spectres de transmission optique calculés et expérimentaux, a été effectué à l'aide d'une modélisation utilisant les théories de Manifacier et de Heavens. / The present work deals with the fabrication of SnS thin films as a potential substitute to CuInS2 absorber material in thin film solar cells. The Chemical Bath Deposition method (CBD) is applied to this binary material, as it is non toxic and relatively inexpensive. Structural, chemical, morphological and optical properties of the fabricated layers are investigated by X-Ray diffraction, profilometry, scanning electron microscopy associated with energy dispersive spectrometry, atomic force microscopy, and visible to infrared spectrophotometry. Annealing and doping of the SnS thin layer is also investigated. Theoretical modelling of the thin film thickness is obtained from optical transmission and reflexion spectra based on the envelope of interference fringes.