Green Spin Light-Emitting Diodes Enabled by Perovskite Nanocrystals <i>in Situ</i> Modified with Chiral Ligands
Desui Chen, Bing Tang, Aleksandr A. Sergeev, Ye Wu, Haochen Liu, Ding Zhu, Sile Hu, Kam Sing Wong, Hin‐Lap Yip, Andrey L. Rogach
Abstract
High Resolution Image Download MS PowerPoint Slide Spin-polarized light-emitting diodes (spin-LEDs) hold promise for next-generation technologies across optical communication, biological imaging, and quantum information processing. Chiral metal halide perovskites, which combine advantageous optoelectronic properties with chirality, are promising materials for high-performance spin-LEDs. However, such spin-LEDs still suffer from low efficiency and limited brightness, as they often rely on low-dimensional chiral perovskites with rather inferior charge-transport properties as spin filter layers. Herein, we demonstrate bright and efficient green spin-LEDs based on chiral perovskite nanocrystals as emitters. We employed an in situ chiral ligand modification using R-/S-1-(4-bromophenyl)-ethylammonium bromide to imprint chirality onto CsPbBr 3 nanocrystals, which exhibited both a high photoluminescence quantum yield of 89% and improved spin relaxation lifetime. A remarkable spin-polarization of 88% was observed for the CsPbBr 3 nanocrystal films. Consequently, our spin-LEDs without a commonly used spin filter layer simultaneously achieved a maximum brightness of 12,800 cd m –2, a record-high peak external quantum efficiency of 15.4%, and a circularly polarized electroluminescence with a dissymmetry factor of 2.16 × 10 –3 at room temperature, setting new benchmarks for perovskite-based spin-LEDs.