Pu Chaodan, Dai Xingliang, Shu Yufei, Zhu Meiyi, Deng Yunzhou, Jin Yizheng, Peng Xiaogang
Centre for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou, 310027, China.
State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, 310027, China.
Nat Commun. 2020 Feb 18;11(1):937. doi: 10.1038/s41467-020-14756-5.
Colloidal quantum dots are promising emitters for quantum-dot-based light-emitting-diodes. Though quantum dots have been synthesized with efficient, stable, and high colour-purity photoluminescence, inheriting their superior luminescent properties in light-emitting-diodes remains challenging. This is commonly attributed to unbalanced charge injection and/or interfacial exciton quenching in the devices. Here, a general but previously overlooked degradation channel in light-emitting-diodes, i.e., operando electrochemical reactions of surface ligands with injected charge carriers, is identified. We develop a strategy of applying electrochemically-inert ligands to quantum dots with excellent luminescent properties to bridge their photoluminescence-electroluminescence gap. This material-design principle is general for boosting electroluminescence efficiency and lifetime of the light-emitting-diodes, resulting in record-long operational lifetimes for both red-emitting light-emitting-diodes (T > 3800 h at 1000 cd m) and blue-emitting light-emitting-diodes (T > 10,000 h at 100 cd m). Our study provides a critical guideline for the quantum dots to be used in optoelectronic and electronic devices.
胶体量子点是基于量子点的发光二极管中很有前景的发光体。尽管已经合成出具有高效、稳定且高色纯度光致发光的量子点，但在发光二极管中继承其优异的发光特性仍然具有挑战性。这通常归因于器件中电荷注入不平衡和/或界面激子猝灭。在此，我们识别出了发光二极管中一个普遍但此前被忽视的退化通道，即表面配体与注入的电荷载流子之间的原位电化学反应。我们开发了一种策略，将具有优异发光特性的电化学惰性配体应用于量子点，以弥合其光致发光与电致发光之间的差距。这种材料设计原则对于提高发光二极管的电致发光效率和寿命具有通用性，使得红色发光二极管（在1000 cd m下T > 3800 h）和蓝色发光二极管（在100 cd m下T > 10,000 h）都实现了创纪录的长工作寿命。我们的研究为用于光电器件和电子器件的量子点提供了关键指导。
