Amino-capped zinc oxide modified tin oxide electron transport layer for efficient perovskite solar cells
Rongjun Zhao, Linqin Wang, Jing Huang, Xiaohe Miao, Licheng Sun, Yong Hua, Yude Wang
Abstract
Electron transport layer (ETL)/perovskite interface passivation is particularly challenging because of the use of polar solvents (e.g., DMF) for perovskite solution deposition, which usually destroy the bottom as-formed defect passivation layers. Herein, a novel multifunctional composite ETL, NH2[email protected]2, is prepared by mixing amino-capped ZnO (NH2-ZnO) nanocrystals (NCs) with SnO2 nanoparticles. The best-performing PSCs on the basis of NH2[email protected]2 achieve efficiency of 22.52%, which is significantly higher than that of the pristine SnO2 counterpart (18.45%). The enhanced performance of the NH2[email protected]2 ETL can be attributed to higher electron extraction capacity, better energy-level alignment with perovskite material, and more efficient carrier transport in device. Most important, the NH2 groups on the surface of ZnO NCs can effectively passivate the under-coordinated Pb2+ ions from perovskite films, thus reducing charge recombination at ETL/perovskite interface. The results suggest that NH2-ZnO [email protected]2 composite is a promising ETL for improving the performance of PSCs.