Bottom interface passivation with benzylamine thiocyanate for improving the performance of inverted perovskite solar cells

Abstract

The organic–inorganic hybrid perovskite materials have attracted a lot of attention in the photovoltaics field due to their excellent photovoltaic properties and simple preparation process in recent years. The well-known hole transport layer PTAA in the inverted perovskite solar cells (PSCs) is prone to trigging the nonradiative recombination and limiting the device performance. Here, we added benzylamine thiocyanate (BnASCN) bottom interface passivation layer between PTAA/perovskite layers to regulate the crystal growth of perovskite film, thus increase the grain size of perovskite film. The amino-passivation of BnA+ and the interaction of the strongly electronegative S and N in pseudo-halogens with the undercoordinated Pb2+, the defect density of the perovskite films is reduced, which effectively reduced the nonradiative recombination and inhibited ion migration, and the device power conversion efficiency improved from 17.12 % to 19.48 %. Moreover, the stability of the device is improved.