Seed-mediated superior organometal halide films by GeO2 nano-particles for high performance perovskite solar cells

The authors developed a seed-mediated method by GeO2 nano-particles (NPs) for growing crystal perovskite films. Poly(3,4-ethylene dioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS)-GeO2 composite films can act as an efficient underlayer for the growth of crystal perovskite films. GeO2 NPs are regarded as the growing sites of crystal nucleus of the perovskites. Superior quality of perovskite films are achieved by tuning the size of the GeO2 NPs, which results in a power conversion efficiency as high as 16.77%. The seed-mediated growing route on perovskite crystallization also gives a hint to seek other nano-particle materials for fabricating highly efficient and stable perovskite solar cells in the future.