Efficient Perovskite Light-Emitting Diodes with Chemically Bonded Contact and Regulated Charge Behavior
Yaping Zhao, Wenjing Feng, Mingliang Li, Jianxun Lu, Xiangqian Qin, Kebin Lin, Jiefeng Luo, Wen‐Hua Zhang, Eng Liang Lim, Zhanhua Wei
Abstract
Efficient charge injection and radiative recombination are essential to achieving high-performance perovskite light-emitting diodes (Pero-LEDs). However, the perovskite emission layer (EML) and the electron transport layer (ETL) form a poor physically interfacial contact and non-negligible charge injection barrier, limiting the device performance. Herein, we utilize a phosphine oxide, 2,4,6-tris[3-(diphenylphosphinyl)phenyl]-1,3,5-triazine (PO-T2T), to treat the perovskite/ETL interface and form a chemically bonded contact. Specifically, PO-T2T firmly bonds on the perovskite’s surface and grain boundaries through a dative bond, effectively passivating the uncoordinated lead defects. Additionally, PO-T2T has high electron mobility and establishes an electron transport highway to bridge the ETL and EML. As a result, a maximum external quantum efficiency (EQE max ) of 22.06% (average EQE max of 20.02 ± 1.00%) and maximum luminance ( L max ) of 103286 cd m –2 have been achieved for the champion device. Our results indicate that EML/ETL interface modifications are crucial for the fabrication of highly efficient Pero-LEDs.