Zhang Jibin, Cai Bo, Zhou Xin, Yuan Fanglong, Yin Chunyang, Wang Heyong, Chen Hongting, Ji Xinzhen, Liang Xiangfei, Shen Chao, Wang Yu, Ma Zhuangzhuang, Qing Jian, Shi Zhifeng, Hu Zhangjun, Hou Lintao, Zeng Haibo, Bai Sai, Gao Feng
Key Laboratory of Materials Physics of Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Daxue Road 75, Zhengzhou, 450052, China.
Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, SE-58183, Sweden.
Adv Mater. 2023 Nov;35(45):e2303938. doi: 10.1002/adma.202303938. Epub 2023 Oct 9.
Achieving high-performance perovskite light-emitting diodes (PeLEDs) with pure-red electroluminescence for practical applications remains a critical challenge because of the problematic luminescence property and spectral instability of existing emitters. Herein, high-efficiency Rec. 2020 pure-red PeLEDs, simultaneously exhibiting exceptional brightness and spectral stability, based on CsPb(Br/I) perovskite nanocrystals (NCs) capping with aromatic amino acid ligands featuring cation-π interactions, are reported. It is proven that strong cation-π interactions between the PbI -octahedra of perovskite units and the electron-rich indole ring of tryptophan (TRP) molecules not only chemically polish the imperfect surface sites, but also markedly increase the binding affinity of the ligand molecules, leading to high photoluminescence quantum yields and greatly enhanced spectral stability of the CsPb(Br/I) NCs. Moreover, the incorporation of small-size aromatic TRP ligands ensures superior charge-transport properties of the assembled emissive layers. The resultant devices emitting at around 635 nm demonstrate a champion external quantum efficiency of 22.8%, a max luminance of 12 910 cd m , and outstanding spectral stability, representing one of the best-performing Rec. 2020 pure-red PeLEDs achieved so far.
由于现有发光体存在发光性能问题和光谱不稳定性，实现具有纯红色电致发光的高性能钙钛矿发光二极管（PeLED）用于实际应用仍然是一项严峻挑战。在此，报道了基于用具有阳离子-π相互作用的芳香族氨基酸配体包覆的CsPb(Br/I)钙钛矿纳米晶体（NCs）的高效Rec. 2020纯红色PeLED，其同时表现出优异的亮度和光谱稳定性。事实证明，钙钛矿单元的PbI八面体与色氨酸（TRP）分子富含电子的吲哚环之间强烈的阳离子-π相互作用不仅在化学上修饰了不完美的表面位点，而且显著提高了配体分子的结合亲和力，导致CsPb(Br/I) NCs具有高光致发光量子产率和大大增强的光谱稳定性。此外，掺入小尺寸的芳香族TRP配体确保了组装发光层具有优异的电荷传输性能。所得在635 nm左右发光的器件表现出22.8%的最佳外量子效率、12910 cd m的最大亮度和出色的光谱稳定性，代表了迄今为止实现的性能最佳的Rec. 2020纯红色PeLED之一。
