Multifunctional urea in modification of SnO2 interface for high efficiency planar perovskite solar cells

Abstract

At present, the unprecedented rapid development of perovskite solar cells (PSCs) shows its great commercial application potential. However, there are many detrimental defects at indium tin-oxide (ITO)/electron transport layer (ETL)/perovskite interface, leading to severe non-radiative recombination and limiting the further improvements in power conversion efficiency (PCE). In this paper, urea is explored for modifying the back and front side of Tin oxides (SnO2) ETL. This study finds that urea pretreatment of SnO2 can achieve the passivation purpose for oxygen vacancies and hydroxyl groups, while adjust energy level of SnO2. As a result, photo-carrier transport is significantly improved and produces a champion PCE of 21.51 % with an open-circuit voltage of 1.141 V based on urea pretreatment device. This work paves a new route for fabricating the better-performing SnO2 ETL.