High-temperature induced iodide and bromide ions filling lattice for high efficient all-inorganic perovskite solar cells

Abstract

All inorganic CsPbX3 perovskites have gained great attentions owing to their excellent carrier transport property and thermal stability. However, the presence of X vacancy in the CsPbX3 lattice results in a high trap density within CsPbX3 films, and subsequently affects the photovoltaic performance of solar cells. Here, we use phenylethylammonium iodide (PEAI) and phenylethylammonium bromide (PEABr) to manipulate the film quality of inorganic perovskites, which significantly improve the moisture-resistance of the CsPbI2Br film and photovoltaic performance. It is found that there is no so-called two-dimensional PEA2PbI4 and PEA2PbBr4 materials formed after a high temperature annealing, but iodine or bromide vacancies can be filled by external anions. The improved film quality with a low trap density renders the enhancement of the perovskite phase stability and the device efficiency of the CsPbI2Br solar cells. This work shows that filling vacancies by external anions can promote perovskite photovoltaic performance and stability.