PhD : ADVANCED HYBRID PEROVSKITES FOR PHOTOVOLTAICS UNDER CONFINEMENT – Contact: Olivier PLANTEVIN
The effect of confinement in porous matrices on the optoelectronic properties of perovskites will be studied. The samples will be synthesized by the Ph.D. student at the LPICM-Ecole Polytechnique in collaboration with Frederic Oswald and Hindia Nahdi. We will focus on single halogen (Iode or Brome) or mixed halogen (Iode and Brome) perovskites with varying relative concentrations. We will study separately thin layers made by perovskite impregnation (liquid phase synthesis) in different mesoporous media, with priority TiO2, ZrO2 and Carbon graphite to compare the role of the media, whether be it semiconductor, insulator or metal on the opto-electronic properties of the thin layer. The architecture of complete cells will also be discussed. The two sides of the cell (graphite and TiO2, the ZrO2 layer playing an insulating role between these two sides) will be studied in a complementary way. A characterization by low temperature photoluminescence spectroscopy will reveal the induced defect levels in the material. The «blue-shift» already observed by our team for confined perovskites, will allow to better characterize the confinement in the different layers of the cell (mesoporous graphite, TiO2 and ZrO2 mesoporous). In particular, the photoinduced mobility of halogen ions (iodine and/or bromine) will be investigated by studying the evolution of emission spectra and the influence of temperature on ion diffusion mechanisms.