Stabilizing electroluminescence color of blue perovskite LEDs via amine group doping

Fengjuan Zhang; Jizhong Song; Bo Cai; Xi Chen; Changting Wei; Tao Fang; Haibo Zeng

doi:10.1016/j.scib.2021.04.033

Stabilizing electroluminescence color of blue perovskite LEDs via amine group doping

Sci Bull (Beijing). 2021 Nov 15;66(21):2189-2198. doi: 10.1016/j.scib.2021.04.033. Epub 2021 Apr 24.

Authors

Fengjuan Zhang¹, Jizhong Song¹, Bo Cai¹, Xi Chen¹, Changting Wei¹, Tao Fang¹, Haibo Zeng²

Affiliations

¹ 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.
² 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. Electronic address: zeng.haibo@njust.edu.cn.

PMID: 36654110
DOI: 10.1016/j.scib.2021.04.033

Abstract

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 (-NH₂) doping source for CsPbBr_xCl_3-_x quantum dots (QDs), experimental and theoretical results reveal that the strong N-H⋯X (X = Br/Cl) bonding can be produced between -NH₂ 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.

Keywords: Amine-group doping; Color stability; Hydrogen bond; Light-emitting diodes; Perovskites; Quantum dots.