Enhanced performance of planar perovskite solar cells by doping the SnO2 electron transport layer with guanidinium chloride
Jiajiu Ye, Yuze Li, Asma Aicha Medjahed, Stéphanie Pouget, Dmitry Aldakov, Yueli Liu, Peter Reiß
Abstract
Tin (IV) oxide is a highly promising electron transport layer (ETL) for lead halide perovskite solar cells due to its high conductivity, transparency, wide band gap, and the possibility of low-temperature processing. Nonetheless, charge carrier recombination processes at the SnO 2 /perovskite interface diminish the device performance. Here, we demonstrate that SnO 2 doping with guanidine hydrochloride (G-SnO 2 ) leads to efficient surface passivation and a larger band offset between the ETL and the perovskite layer, resulting in reduced voltage losses and faster electron transfer. Moreover, G-SnO 2 facilitates the growth of highly crystalline perovskite layers. Consequently, a power conversion efficiency of up to 23.48% and a high open-circuit voltage of 1.18 V are obtained in solar cells incorporating the G-SnO 2 ETL. These devices also exhibited negligible hysteresis and maintained more than 96% of their initial power conversion efficiency after 1,250 h exposure to the air without encapsulation.