Enhancing Interface Interaction through Multifunctional Trisodium Citrate Modification of Electron‐Transport Layer in Fully Air‐Processed Perovskite Solar Cells

Abstract

Electron transport layer (ETL) is integral in conventional perovskite solar cells (PSCs), serving as an essential role in both the growth of perovskite and the extraction of charge carriers. This dual functionality poses a challenge, especially in the context of the ETL in all‐air‐processed PSCs. Here, a multifunctional modification strategy is proposed, where trisodium citrate (TC) is incorporated into SnO2 precursor. The introduction of TC can efficiently inhibit the agglomeration of SnO2 nanoparticle in precursor. This also eliminates the oxygen vacancy defects and reduces the work function of the SnO2 film surface. This synergistic effect remarkably improves the quality of electron transport layer. Meanwhile, TC can passivate the undercoordinated Pb2+ at the buried interface, thus suppressing non‐radiative recombination and reducing lead leakage. Furthermore, Na ions in the TC molecule facilitate the perovskite crystallization by migrating into the perovskite layer, resulting in formation of a high‐quality perovskite film. Consequently, the efficiency of the TC‐treated device made in fully‐ambient‐air conditions reaches 21.17% with suppressing hysteresis. In particular, the unencapsulated device maintains about 81% of the original efficiency after 2500 hours under air exposure. This study presents a straightforward and effective method for achieving efficient and stable air‐processed PSCs.This article is protected by copyright. All rights reserved.