A Facile Low Temperature Fabrication of High Performance CsPbI2Br All-Inorganic Perovskite Solar Cells

All-inorganic lead halide perovskites alpha-CsPbI2Br with higher thermal stability and phase stability are promising candidate for optoelectronic application such as photovoltaics. However, the >250 degrees C high temperature annealing is required to obtain the desired photovoltaic active perovskite phase of alpha-CsPbI2Br, which makes it difficult for fabrication and application based on flexible polymer substrate. Here, a facile formation of high performance allinorganic CsPbI2Br perovskite solar cell is reported, through a one-step method and a 100-130 degrees C low temperature annealing process. The facile-deposited CsPbI2Br film demonstrates long-term phase stability at room temperature for a month and exhibits the thermal stability under 100 degrees C annealing for more than a week. Consequently, the CsPbI2Br-based allinorganic perovskite solar cells (PSCs) exhibit power conversion efficiencies (PCE) of up to a record value of 10.56%. This low temperature crystallization of all-inorganic CsPbI2Br perovskite is a promising approach for scalable, convenient, and inexpensive fabrication in the future.