High‐purity synthesis of all‐inorganic CsPbBr 3 perovskite powder assisted by solubilizing organic ligand and its application to perovskite solar cells

All-inorganic perovskites have shown promising performances with high thermal stabilities when used as photoactive materials for optoelectronic applications. Therefore, the development of cost-effective, high-quality, and massive production methods of all-inorganic perovskites has emerged as an important task for the commercialization of perovskite-based optoelectronics. We developed a facile preparation method for all-inorganic CsPbBr3 perovskite powder by incorporating an organic ligand that enables Cs precursor to maintain high solubility during synthesis. The synthesized CsPbBr3 powder was verified for its cost-effectiveness and high purity due to an appropriate selection of thermally-decomposable precursors and effective removal of residue during the purification step. Furthermore, we found that the CsPbBr3 film prepared from our synthesized powder provided an improved homogeneity and a reduction of defects compared with that prepared from conventional metal halide precursor, which is attributed to the suppression of non-stoichiometry and impurity phase. Therefore, the perovskite solar cells fabricated using our CsPbBr3 powder offered improved power conversion efficiency (PCE) of 8.19% and stability than the control device from metal halide precursor (5.90%).