Zeng Xiankan, Yin Qiming, Pan Lunyao, Chen Yongjian, Li Chenglong, Mu Maolin, Wang Qungui, 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.
Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, P. R. China.
ACS Nano. 2025 Apr 1;19(12):11878-11890. doi: 10.1021/acsnano.4c14429. Epub 2025 Mar 19.
CsCuI light-emitting diodes (LEDs) have attracted tremendous interest due to their environmental friendliness, low-cost processing, and broadband luminescence properties. However, their hole injection efficiency usually towers over electron injection efficiency owing to the intrinsic Cu vacancy-mediated excess hole concentration and wide bandgap of CsCuI, generating severe charge imbalance. Here, we designed an inorganic interfacial dipole layer (IDL) based on lithium chloride to exert a hole delayed-release effect for charge balance in CsCuI LEDs by selectively modulating the energy levels of the contact layers. Accordingly, the IDL-based CsCuI LEDs exhibit a record champion brightness of 2620 cd/m along with a three times enhanced peak external quantum efficiency of 3.73% at 565 nm. Meanwhile, the universality of the hole delayed-release effect of inorganic IDLs is verified by demonstrating enhanced CsCuI LEDs incorporated with other alkali metal salt-based IDLs. This work provides a comprehensive guideline for optimizing the charge transport of lead-free LEDs by charge delayed-release effect of IDLs toward next-generation eco-friendly display applications.
CsCuI发光二极管（LED）因其环境友好、低成本加工以及宽带发光特性而备受关注。然而，由于CsCuI固有的铜空位介导的过量空穴浓度和宽带隙，其空穴注入效率通常高于电子注入效率，从而产生严重的电荷失衡。在此，我们设计了一种基于氯化锂的无机界面偶极层（IDL），通过选择性地调节接触层的能级，对CsCuI LED中的电荷平衡施加空穴延迟释放效应。相应地，基于IDL的CsCuI LED表现出创纪录的2620 cd/m的冠军亮度，以及在565 nm处三倍增强的3.73%的峰值外量子效率。同时，通过展示与其他碱金属盐基IDL结合的增强型CsCuI LED，验证了无机IDL空穴延迟释放效应的普遍性。这项工作为通过IDL的电荷延迟释放效应优化无铅LED的电荷传输提供了全面的指导方针，以用于下一代环保显示应用。
