One-step Solution-Processed Formamidinium Lead Tribromide Formation for Better Reproducible Planar Perovskite Solar Cells

Abstract

Low-cost solar cells based on solution-processed organic–inorganic hybrid perovskites with high photovoltage are highly sought after, especially for their use in tandem cells or for driving electrochemical reactions. Towards this end, we herein present a single-step method for the preparation of regular planar heterojunction solar cells based on formamidinium lead tribromide (FAPbBr3), which is fabricated through an antisolvent-assisted crystallization process. This results in the formation of improved film quality of the perovskite layer in terms of uniformity, surface coverage, crystallinity, and light absorption. Devices fabricated using such films utilizing 2,2′,7,7′-tetrakis-(N,N-p-dimethoxyphenylamino)-9,9′-spirobifluorene (spiro-OMeTAD) as the hole-transport layer exhibits an open-circuit voltage (Voc) of 1.32 V with a power conversion efficiency (PCE) close to 6 %. The device performance is much higher than when using devices based on the conventional one-step process (i.e., without using an antisolvent), where a Voc of 1.04 V and a PCE of 1.1 % are obtained. Moreover, the devices show better reproducibility with very little hysteresis.