Perovskite CsPbI 2 Br Thin Films Prepared under Nitrogen Flow and Black Phase Stabilization in the Presence of a Two‐Dimensional Inorganic Halide Material and Indium

International audienceIn this work, a simple thin films manufacturing process of all-inorganic halide perovskites has been developed under ambient conditions. A flow of nitrogen placed above the freshly deposited film by spin-coating, during the brief heat treatment stage, provides a suitable microstructure for photovoltaic applications. The main parameters of this process have been tested in order to obtain the most suitable perovskite layer for solar cells. Films of 3D CsPbI2Br, mixtures of [3D+2D] phases where Cs2PbCl2I2 is the 2D material, and in the presence of indium in order to substitute lead in the main phase, were optimized and their structures analyzed by means of scanning electron microscopy and X-ray diffraction. Films are more compact and the structure tends to be more symmetrical upon doping, which preserve the black phase for a longer time. Each type of film was integrated into a fully functional solar cell. The addition of the 2D material to the main 3D phase affect the photovoltaic performances of the manufactured devices under our conditions but the photoactive black phase is clearly stabilized. A preferred orientation was observed in the presence of the 2D material and under nitrogen flow. Texture analysis evidenced for a fiber-like structure and the presence of indium tends to improve the black phase stability