Key Words:Ion exchange;Electron transport properties - Grain boundaries - Grain growth - Ions - Open circuit voltage - Optoelectronic devices - Passivation - Perovskite - Perovskite solar cells - Surface defects

Abstract:Interface engineering is of great concern in photovoltaic devices. For the solution-processed perovskite solar cells, the modification of the bottom surface of the perovskite layer is a challenge due to solvent incompatibility. Herein, a Cl-containing tin-based electron transport layer; SnO<inf>x</inf>-Cl, is designed to realize an in situ, spontaneous ion-exchange reaction at the interface of SnO<inf>x</inf>-Cl/MAPbI<inf>3</inf>. The interfacial ion rearrangement not only effectively passivates the physical contact defects, but, at the same time, the diffusion of Cl ions in the perovskite film also causes longitudinal grain growth and further reduces the grain boundary density. As a result, an efficiency of 20.32% is achieved with an extremely high open-circuit voltage of 1.19 V. This versatile design of the underlying carrier transport layer provides a new way to improve the performance of perovskite solar cells and other optoelectronic devices.<br/> © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Volume:9

Issue:38

Translation or Not:no