基于 HEDTA 配体修饰的纯红色 CsPb(Br/I)₃ 钙钛矿发光二极管

Recently，perovskite light-emitting diodes（PeLEDs）have shown excellent properties such as ultra-high color purity，ultra-wide color gamut，and high luminous efficiency. In particular，the external quantum efficiency （EQE）and brightness of green and near-infrared light PeLEDs had been rapidly improved，but the performance（effi⁃ ciency，brightness，reliability，etc.）of pure-red PeLEDs with emission peak at 620-640 nm developed relatively slowly. In this paper，the pure-red mixed halogen perovskite CsPb（Br/I）₃ nanocrystals were successfully prepared by a traditional hot injection combined with post-treatment process based on N-hydroxyethyl ethylenediamine triacetic acid（HEDTA）ligands. The optical properties and stability were significantly improved. HEDTA multi-dentate li⁃ gands effectively bound to Pb²⁺ and I^- on the surface of nanocrystals to passivate the surface defects related to Pb²⁺ ions，and at the same time，inhibited the formation of I^- Frankel defects that usually lead to halide segregation. Final⁃ ly，PeLEDs encapsulated with HEDTA treated CsPb（Br/I）₃ nanocrystals as a luminescent layer achieved a pure-red emission peaked at 636 nm as well as a maximum EQE and luminnace of 18. 62% and 1 880 cd/m²，respectively.