AUTHOR=Ye Jiajiu , Li Yuze , Medjahed Asma Aicha , Pouget Stéphanie , Aldakov Dmitry , Liu Yueli , Reiss Peter 

TITLE=Enhanced performance of planar perovskite solar cells by doping the SnO2 electron transport layer with guanidinium chloride

JOURNAL=Frontiers in Materials

VOLUME=10

YEAR=2023

URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2023.1118641

DOI=10.3389/fmats.2023.1118641

ISSN=2296-8016

ABSTRACT=<p>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<sub>2</sub>/perovskite interface diminish the device performance. Here, we demonstrate that SnO<sub>2</sub> doping with guanidine hydrochloride (G-SnO<sub>2</sub>) 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<sub>2</sub> 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<sub>2</sub> 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.</p>