Synthesis of ligand-free, large scale with high quality all-inorganic CsPbI3 and CsPb2Br5 nanocrystals and fabrication of all-inorganic perovskite solar cells

All-inorganic based cesium lead-halide (CsPbX3) perovskite nanocrystals have emerged as an attractive nanomaterials owing to their stability and excellent optoelectronic properties. Here, we report synthesis of high quality orthorhombic phase of CsPbI3 and tetragonal structure of the CsPb2Br5 nanostructures by various methods. In addition, we fabricated all inorganic based solar cell devices using highly stable CuSCN as hole transport material (HTM) and cost effective carbon-graphite composites as contact layer. Current–voltage measurements shows 0.74% efficiency for a yellow phase CsPbI3 perovskite while the power conversion efficiency of black phase CsPbI3 reach 6.9%. Moreover, tetragonal structure of CsPb2Br5 shows 2.82% using the similar architecture. Sandwich type architecture (FTO/bl-TiO2/m-TiO2/Perovskite/CuSCN/C:G) employed for the fabrication of both devices. This work offer a new avenue to prepare large scale with high-quality inorganic perovskite materials and fabrication of high efficiency all-inorganic perovskite solar cells (PSCs).