Preparation of CsPbBr<sub>3</sub> Films for Efficient Perovskite Solar Cells from Aqueous Solutions
Xiaobing Ding, Yukai Zhang, Fang Sheng, Yanqing Li, Lili Zhi, Xiaobing Cao, Xian Cui, Daming Zhuang, Jinquan Wei
Abstract
Toxic organic solvents are widely used in fabricating perovskite solar cells, which pose a potential threat to human health and the environment. Here, we try to prepare high-quality all-inorganic perovskite films from all aqueous solutions using a traditional two-step method. A continuous PbBr2 precursor film is first prepared from a HBr/H2O solution added with a certain amount of poly(ethylene glycol) (PEG). The PEG plays important roles in adjusting the viscosity of the aqueous solution and affecting the growth of the PbBr2 precursor crystals. A high concentration of the CsBr/H2O solution is then spin-coated on the PbBr2 precursor film followed by annealing to form a high-quality CsPbBr3 film. The CsPbBr3 perovskite solar cells prepared from the aqueous solutions show an efficiency of 7.19%, which is higher than those prepared from the organic solvents in the same conditions. It is a facile and green method to eliminate the solvent toxicity derived from organic solvents in fabricating perovskite solar cells.