Small-Molecule Copper Chloride Modulating the Buried Interfaces of Perovskite Solar Cells
Qi Chen, Jihuai Wu, Xuping Liu, Yitian Du, Chunyan Deng, Xia Chen, Liuxue Sun, Lina Tan, Weihai Sun, Zhang Lan
Abstract
In perovskite solar cells (PSCs), tin dioxide (SnO 2 ) is a highly effective electron transport material. On the other hand, the low intrinsic conductivity of SnO 2, the high trap-state density on the surface and bulk of SnO 2, and inadequate interface contacts between SnO 2 and perovskite significantly impact device performance. Herein, small-molecule copper(II) chloride (CuCl 2 ) is introduced into the SnO 2 dispersion, which inhibits the agglomeration of SnO 2 colloids and improves the quality of the electron transport layer. Furthermore, the introduction of CuCl 2 optimizes the energy-level array between the ETL and perovskite layer (PVK) and passivates the anion/cation defects in SnO 2, perovskite, and their interface, realizing the systematic modulation of the photoelectronic properties of the ETLs and PVKs as well as the PVK/ETL. As a result, the CuCl 2 -opmized PSC exhibits an impressive power conversion efficiency of 23.71%, along with improved stability.