The preparation of all-inorganic CsPbI2−xBr1+x perovskite solar cells based on electrodeposited PbO2 film

All-inorganic perovskites have attracted intense interest as light-absorbing materials, due to their large absorption coefficient, long charge carrier and diffusion length. However, it is a challenge to obtain the large-area synthesis of high-quality uniform perovskites layers. Here we demonstrate the applicability of the electrodeposition technique for the large-area fabricating of all-inorganic perovskite layers. PbO 2 films were firstly electrodeposited on c-TiO 2 /m-TiO 2 /FTO substrate, which is then converted to PbI 2 and CsPbI 2−x Br 1+x sequentially. By optimizing the preparation process, we have obtained a large area and high-quality CsPbI 2−x Br 1+x perovskite thin film, which exhibited strong UV–visible light absorption. Moreover, adding an appropriate amount of DMF solution to the CsBr-methanol solution can promote the reaction between CsBr and PbI 2 , could increase the grain size of the perovskite grain and could improve the density of the perovskite film. A power conversion efficiency of 6.87% is obtained for small cells (0.25 cm 2 ) and 2.84% for large size cells (1.5 cm 2 ) using the c-TiO 2 /m-TiO 2 /CsPbI 2−x Br 1+x /Carbon structure.