Li Hanming, Lin Hong, Ouyang Dan, Yao Canglang, Li Can, Sun Jiayun, Song Yilong, Wang Yufeng, Yan Yanfa, Wang Yong, Dong Qingfeng, Choy Wallace C H
Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, 999077, China.
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, China.
Adv Mater. 2021 Apr;33(15):e2008820. doi: 10.1002/adma.202008820. Epub 2021 Mar 9.
The long-term operational stability of perovskite light-emitting diodes (PeLEDs), especially red PeLEDs with only several hours typically, has always faced great challenges. Stable β-CsPbI nanocrystals (NCs) are demonstrated for highly efficient and stable red-emitting PeLEDs through incorporation of poly(maleic anhydride-alt-1-octadecene) (PMA) in synthesizing the NCs. The PMA can chemically interact with PbI in the precursors via the coupling effect between O groups in PMA and Pb to favor crystallization of stable β-CsPbI NCs. Meanwhile, the cross-linked PMA significantly reduces the Pb anti-site defect on the surface of the β-CsPbI NCs. Benefiting from the improved crystal phase quality, the photoluminescence quantum yield for β-CsPbI NCs films remarkably increases from 34% to 89%. The corresponding red-emitting PeLEDs achieves a high external quantum efficiency of 17.8% and superior operational stability with the lifetime, the time to half the initial electroluminescence intensity (T ) reaching 317 h at a constant current density of 30 mA cm .
钙钛矿发光二极管（PeLEDs）的长期运行稳定性一直面临着巨大挑战，尤其是红色PeLEDs，其典型寿命通常只有几个小时。通过在合成纳米晶体（NCs）时引入聚（马来酸酐-alt-1-十八碳烯）（PMA），展示了稳定的β-CsPbI纳米晶体用于高效稳定的红色发光PeLEDs。PMA可以通过PMA中O基团与Pb之间的偶联效应与前驱体中的PbI发生化学相互作用，有利于稳定的β-CsPbI NCs的结晶。同时，交联的PMA显著减少了β-CsPbI NCs表面的Pb反位缺陷。受益于改善的晶相质量，β-CsPbI NCs薄膜的光致发光量子产率从34%显著提高到89%。相应的红色发光PeLEDs实现了17.8%的高外量子效率和优异的运行稳定性，在30 mA cm²的恒定电流密度下，初始电致发光强度减半的时间（T₅₀）达到317小时。
