近日，上海大学杨绪勇团队研究了高效白光发光二极管用半导体量子点的局部点阵软化。相关论文于2025年7月16日发表在《自然—光子学》杂志上。
基于单组分量子点的白光发光二极管（sc-WQLEDs）由于其低工作电压和高光谱稳定性而受到广泛关注。然而，由于缺乏高效的白色量子点发射器，它们的性能目前远远落后于最先进的白色有机LED。在半导体量子点中产生自困激子是一种很有前途的产生宽带白光的方法。然而，这种发射体通常存在电荷输运差和结构不稳定的问题。
研究组通过杂价掺杂卤素离子使ZnSe核的局部晶格软化，将尖锐的激子蓝色发射与宽带自捕获的黄色激子发射相结合，实现了具有高效白光发射的核/壳结构ZnSe/ZnS量子点的可控合成。研究组发现，束缚在周围ZnSe共价矩阵中的自捕获激子可以产生强而稳定的黄色发射，而ZnSe的激子蓝色发射和电荷输运能力却最小。
基于该方法，研究组成功制备出高效无重金属白色量子点发光二极管(WQLEDs)，其最大外量子效率达15%（平均值10.5±2.6%），亮度超过26,000 cd m−2，并展现出卓越的器件工作寿命——在100 cd m−2初始亮度下，T50寿命超过2,500小时。
附：英文原文
Title: Local lattice softening in semiconductor quantum dots for efficient white light-emitting diodes
Author: Wang, Sheng, Wang, Chao, Wang, Yuankun, Long, Tengfei, Liu, Zirui, Wang, Lin, Wang, Haihui, Wu, Qianqian, Zhang, Jianhua, Li, Biwen, Dai, Linjie, Seong, Sijun, Chen, Jiayi, Zhao, Guangjiu, Jia, Guohua, Sun, Haoxiang, Zhang, Wei, Chen, Jun, Bai, Xue, Zhang, Jiaqi, Stranks, Samuel D., Friend, Richard H., Gong, Xiwen, Yang, Xuyong
Issue&Volume: 2025-07-16
Abstract: White light-emitting diodes based on single-component quantum dots (sc-WQLEDs) have gained great attention owing to their low operating voltage and the high spectral stability of their emission. However, their performance presently lags far behind that of state-of-the-art white organic LEDs owing to a lack of efficient white quantum dot emitters. Creating self-trapped excitons in semiconductor quantum dots is a promising approach to producing broadband white emission. However, such emitters generally suffer from poor charge transport and structural instability. Here we accomplish controllable synthesis of core/shell structured ZnSe/ZnS quantum dots with efficient white emission through combining a sharp excitonic blue emission with a broadband yellow self-trapped exciton emission owing to local lattice softening of ZnSe cores by heterovalent doping with halogen ions. We reveal that the self-trapped excitons confined in the surrounding ZnSe covalent-bond matrix can generate strong and stable yellow emission with minimal reduction of the excitonic blue emission and charge transport capability of ZnSe. On the basis of this approach, we demonstrate highly efficient, heavy-metal-free WQLEDs with a maximum external quantum efficiency up to 15% (average 10.5±2.6%), a luminance of over 26,000cdm2 as well as exceptional device operational lifetime with T50 exceeding 2,500h at an initial luminance of 100cdm2.
DOI: 10.1038/s41566-025-01716-y
Source: https://www.nature.com/articles/s41566-025-01716-y