In situ Ligand‐Managed SnO<sub>2</sub> Electron Transport Layer for High‐Efficiency and Stable Perovskite Solar Cells
Yulu Sun, Ruoyao Xu, Lin Yang, Jinfei Dai, Xinyi Zhu, Xiangrong Cao, Peizhou Li, Hebing Tang, Tao Liu, Daolei Mo, Yunxuan Wang, Jingrui Li, Yuan Fang, Bo Jiao, Zhaoxin Wu, Hua Dong
Abstract
Abstract Tin oxide (SnO 2 ) with high conductivity and excellent photostability has been considered as one of the most promising materials for efficient electron transport layer (ETL) in perovskite solar cells (PSCs). Among them, SnO 2 nanoparticles (NPs) dispersions have been extensively utilized due to their facile film formation. However, the inherent defects and agglomeration issues of SnO 2 NPs, as well as the limited tunability and instability of the post‐treatment process for surface/interface engineering strategy, still hinder its further applications. Herein, a ligand‐management strategy implemented during the in situ synthesis of NPs that can effectively achieve uniform modification of NPs is proposed. During the synthesis of SnO 2 NPs, the grafting reaction between diethyl 2‐chloromalonate (DCMA) and the surface of SnO 2 NPs is completed. Compared with the post‐treatment process, this intrinsic DCMA‐passivated SnO 2 (DCMA‐SnO 2 ) effectively reduces the trap state density at the interface between perovskite and ETL while enhancing surface chemical stability. Consequently, PSCs based on DCMA‐SnO 2 achieve a champion PCE of 25.39% for small cells (active area of 0.0655 cm 2 ) and 20.61% for solar modules (active area of 23.25 cm 2 ), demonstrating excellent shelf‐life/light soaking stability (advanced level of ISOS stability protocols). This ligand‐management strategy exhibits significant application potential in preparing high‐efficiency large‐area PSCs.