近日，河南大学的申怀彬&王丽及其研究小组与中国科学技术大学的樊逢佳等人合作并取得一项新进展。经过不懈努力，他们通过能量景观展平实现低电压驱动的高亮度稳定量子点发光二极管。相关研究成果已于2025年1月16日在国际知名学术期刊《光：科学与应用》上发表。

本文引入了一种以“巨型”全合金CdZnSe/ZnSeS核/壳量子点（尺寸约19纳米）作为发光层，来构建高效稳定的量子点发光二极管（QLED）。所合成的CdZnSe基量子点显示出减小的基态带分裂、较浅的价带最大值以及改善的准费米能级分裂，这有效地平整了量子点层与空穴传输层之间的能量分布。更高的电子浓度和加速的空穴注入显著促进了载流子的辐射复合动力学。

因此，CdZnSe基器件展现出高达27.3%的功率转换效率（PCE）和极低的效率衰减，同时在低驱动电压范围（1.8-3.0V）内保持超过25%的高外量子效率（EQE），且产热低。在100%和120%的带隙电压下，分别实现了1400和8600 cd/m²的创纪录高亮度水平。

同时，这些LED在1000 cd/m²的亮度下，展现出了前所未有的工作寿命T₉₅（亮度降低至95%的时间）为72968小时。我们的工作为溶液处理光电子器件在量子点相关界面平整能量分布提供了一条新途径。

据悉，溶液处理量子点发光二极管（QLED）作为显示和照明应用的竞争候选技术，具有巨大潜力。然而，量子点（QD）与空穴传输层（HTL）之间严重的能量失配，使得在低电压范围内实现高性能器件面临挑战。

附：英文原文

Title: Realizing low voltage-driven bright and stable quantum dot light-emitting diodes through energy landscape flattening

Author: Liu, Yiting, Sun, Yingying, Yan, Xiaohan, Li, Bo, Wang, Lei, Li, Jianshun, Sun, Jiahui, Guo, Yaqi, Liu, Weipeng, Hu, Binbin, Lin, Qingli, Fan, Fengjia, Shen, Huaibin

Issue&Volume: 2025-01-16

Abstract: Solution-processed quantum dot light-emitting diodes (QLEDs) hold great potential as competitive candidates for display and lighting applications. However, the serious energy disorder between the quantum dots (QDs) and hole transport layer (HTL) makes it challenging to achieve high-performance devices at lower voltage ranges. Here, we introduce “giant” fully alloy CdZnSe/ZnSeS core/shell QDs (size ~ 19nm) as the emitting layer to build high-efficient and stable QLEDs. The synthesized CdZnSe-based QDs reveal a decreased ground-state band splitting, shallow valence band maximum, and improved quasi-Fermi level splitting, which effectively flatten the energy landscape between the QD layer and hole transport layer. The higher electron concentration and accelerated hole injection significantly promote the carrier radiative recombination dynamics. Consequently, CdZnSe-based device exhibits a high power conversion efficiency (PCE) of 27.3% and an ultra-low efficiency roll-off, with a high external quantum efficiency (EQE) exceeding 25% over a wide range of low driving voltages (1.8-3.0V) and low heat generation. The record-high luminance levels of 1,400 and 8,600cdm^-2 are achieved at bandgap voltages of 100% and 120%, respectively. Meanwhile, These LEDs show an unprecedented operation lifetime T₉₅ (time for the luminance to decrease to 95%) of 72,968h at 1,000cdm^-2. Our work points to a novel path to flatten energy landscape at the QD-related interface for solution-processed photoelectronic devices.

DOI: 10.1038/s41377-024-01727-4

Source: https://www.nature.com/articles/s41377-024-01727-4