posted on 2022-08-29, 16:07authored byJinpeng Wu, Ming-Hua Li, Yan Jiang, Qiaoling Xu, Lede Xian, Haodan Guo, Jing Wan, Rui Wen, Yanyan Fang, Dongmei Xie, Yan Lei, Jin-Song Hu, Yuan Lin
Metal
oxides are the most efficient electron transport layers (ETLs)
in perovskite solar cells (PSCs). However, issues related to the bulk
(i.e., insufficient electron mobility, unfavorable energy level position)
and interface of metal oxide/perovskite (detrimental surface hydroxyl
groups) limit the transport kinetics of photoinduced electrons and
prevent PSCs from unleashing their theoretical efficiency potential.
Herein, the inorganic InP colloid quantum dots (CQDs) with outstanding
electron mobility (4600 cm2 V–1 s–1) and carboxyl (−COOH) terminal ligands were
uniformly distributed into the metal oxide ETL to form consecutive
electron transport channels. The hybrid InP CQD-based ETL demonstrates
a more N-type characteristic with more than 3-fold improvement in
electron mobility. The formation of the Sn–O–In bond
facilitates electron extraction due to suitable energy level alignment
between the ETL and perovskite. The strong interaction between uncoordinated
Pb2+ at the perovskite/ETL interface and the −COO– in the ligand of InP CQDs reduces the density of defects
in perovskite. As a result, the hybrid InP CQD-based ETL with an optimized
InP ratio (18 wt %) boosts the power conversion efficiency of PSCs
from 22.38 to 24.09% (certified efficiency of 23.43%). Meanwhile,
the device demonstrates significantly improved photostability and
atmospheric storage stability.