Efficient and Stable Mg2+-Doped CsPbCl3 Nanocrystals for Violet LEDs.

It has been a challenge to prepare perovskite violet light-emitting diodes due to the low luminous efficiency and poor stability of the relevant materials. In this work, the defect state density of CsPbCl3 NCs was reduced by Mg2+ doping, so the photoluminescence quantum efficiency (PLQY) was increased by 57 times (from 1.3% to 75.8%) compared with undoped CsPbCl3 NCs. The doped CsPbCl3 NCs had no phase change in the atmosphere over 180 days, and the PLQY was only dropped by 19%. Based on the highly efficient luminescence and high stability of Mg2+-doped CsPbCl3 NCs, violet-light-emitting diodes were fabricated. The maximum brightness of device was 135 cd/m2, and the peak EQE reached 0.1%.