Simultaneous Formation of CH3NH3PbI3 and electron transport layers using antisolvent method for efficient perovskite solar cells

Abstract

A new antisolvent method was developed to prepare CH3NH3PbI3 and electron transport layers for making efficient hybrid perovskite solar cells. By directly using [6,6]-phenyl-C61-butyric acid methyl ester in chlorobenzene solution as antisolvent, CH3NH3PbI3 and electron transport layers were simultaneously formed in the films. This method not only simplifies the fabrication process of devices, but also produces uniform perovskite films and improves the interfacial structures between CH3NH3PbI3 and electron transport layers. Large perovskite grains were observed in these films, with the average grain size of >1 μm. The so-formed CH3NH3PbI3/electron transport layers demonstrated good optical and charge transport properties. And perovskite solar cells fabricated using these simultaneously-formed layers achieved a higher power conversion efficiency of 16.58% compared to conventional antisolvent method (14.92%). This method reduces nearly 80% usage of chlorobenzene during the fabrication, offering a more facile and environment-friendly approach to fabricate efficient perovskite solar cells than the conventional antisolvent method.