Pan Lunyao, Zeng Xiankan, Qu Yuanxiao, Mu Maolin, Yang Shiyu, Chen Yongjian, Li Chenglong, Dai Linzhu, Tao Li, Xin Hongqiang, Li Wen, Yang Weiqing
Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, P. R. China.
School of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, P. R. China.
Small. 2024 Nov;20(48):e2405528. doi: 10.1002/smll.202405528. Epub 2024 Sep 6.
CuZnSnS (CZTS) is strong candidate for hole transport in perovskite light emitting diodes (PeLEDs) due to their cost-effectiveness, deep highest occupied molecular orbital (HOMO), and high hole mobility. However, its inherent polymetallic ions usually deteriorate the quality of the perovskite emission layer (EML) affecting device performance. In this study, a bidirectional anchoring strategy is proposed by adding 15-crown-5 ether (15C5) into CZTS hole transport layer (HTL) to suppress the reaction between HTL and EML. The 15C5 molecule interacts with Cu, Zn and Sn cations forming host-guest complexes to impede their migration, which is elucidated by density functional theory calculations. Additionally, 15C5 can neutralize lead (Pb) defects by the abundant oxygen (O) and high electronegative cavities to reduce the nonradiative recombination of FAPbBr film. This bidirectional anchoring strategy effectively improves hole charge transport efficiency and suppresses nonradiative recombination at the HTL/EML interface. As a result, the optimized PeLEDs present a 3.5 times peak external quantum efficiency (EQE) from 3.12% to 11.08% and the maximum luminance (L) increased from 24495 to 50584 cd m. These findings offer innovative insights into addressing the metal ion migration issue commonly observed in inorganic HTLs.
