Zhang Fengjuan, Song Jizhong, Cai Bo, Chen Xi, Wei Changting, Fang Tao, Zeng Haibo
School of Materials Science and Engineering, MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics & Nanomaterials, Nanjing University of Science and Technology, Nanjing 210094, China.
School of Materials Science and Engineering, MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics & Nanomaterials, Nanjing University of Science and Technology, Nanjing 210094, China.
Sci Bull (Beijing). 2021 Nov 15;66(21):2189-2198. doi: 10.1016/j.scib.2021.04.033. Epub 2021 Apr 24.
Voltage loading-induced change in the electroluminescence (EL) wavelength of mixed halide perovskite light-emitting diodes (PeLEDs), so-called color-shift, has become an inevitable phenomenon, which is seriously unfavorable to their applications in lighting and display. Here, we achieve color-stable blue PeLEDs via a hydrogen-bonded amine-group doping strategy. Selecting guanidine (GA) or formamidinium (FA) as amine-group (-NH) doping source for CsPbBrCl quantum dots (QDs), experimental and theoretical results reveal that the strong N-H⋯X (X = Br/Cl) bonding can be produced between -NH dopants and Pb-X lattices, thereby increasing the migration barrier of halide anions. Resultantly, color-stable sky-blue devices were realized with emission peaks fixed at 490.5 (GA) and 492.5 (FA) nm without any obvious shift as the voltage increases, in sharp contrast devices without N-H⋯X producing a 15 nm red-shift from 487 to 502 nm. Not only that, maximum external quantum efficiency is improved to 3.02% and 4.14% from the initial 1.3%. This finding offers a convenient boulevard to achieve color-stable PeLEDs with high efficiency.
电压加载引起的混合卤化物钙钛矿发光二极管（PeLEDs）的电致发光（EL）波长变化，即所谓的颜色偏移，已成为一种不可避免的现象，这对其在照明和显示中的应用极为不利。在此，我们通过氢键胺基掺杂策略实现了颜色稳定的蓝色PeLEDs。选择胍（GA）或甲脒（FA）作为CsPbBrCl量子点（QDs）的胺基（-NH）掺杂源，实验和理论结果表明，-NH掺杂剂与Pb-X晶格之间可形成强N-H⋯X（X = Br/Cl）键，从而增加卤化物阴离子的迁移势垒。结果，实现了颜色稳定的天蓝色器件，其发射峰固定在490.5（GA）和492.5（FA）nm，随着电压增加没有明显偏移，与之形成鲜明对比的是，没有N-H⋯X的器件从487到502 nm产生了15 nm的红移。不仅如此，最大外量子效率从最初的1.3%提高到了3.02%和4.14%。这一发现为实现高效颜色稳定的PeLEDs提供了一条便捷途径。
