Morphology Controlling of All‐Inorganic Perovskite at Low Temperature for Efficient Rigid and Flexible Solar Cells

Abstract

AbstractAll‐inorganic cesium lead halide (CsPbX3) perovskites have emerged as promising photovoltaic materials owing to their superior thermal stability compared to traditional organic–inorganic hybrid counterparts. However, the CsPbX3 perovskites generally need to be prepared at high‐temperature, which restricts their application in multilayer or flexible solar cells. Herein, the formation of CsPbX3 perovskites at room‐temperature (RT) induced by dimethylsulphoxide (DMSO) coordination is reported. It is further found that a RT solvent (DMSO) annealing (RTSA) treatment is valid to control the perovskite crystallization dynamics, leading to uniform and void‐free films, and consequently a maximum power conversion efficiency (PCE) of 6.4% in the device indium tin oxide (ITO)/NiO x /RT‐CsPbI2Br/C60/Bathocuproine (BCP)/Ag, which is, as far as it is known, the first report of RT solution‐processed CsPbX3‐based perovskite solar cells (PSCs). Moreover, the efficiency can be boosted up to 10.4% by postannealing the RTSA‐treated perovskite film at an optimal temperature of 120 °C. Profiting from the moderate temperature, flexible PSCs are also demonstrated with a maximum PCE of 7.3% for the first time. These results may stimulate further development of all‐inorganic CsPbX3 perovskites and their application in flexible electronics.