Post-Passivation of Perovskite Quantum Dots by Conjugated Molecules for Spectrally Stable and Efficient Deep Blue Light-Emitting Diodes

摘要

Perovskite light-emitting diodes (PeLEDs) are promising candidates for displays and solid-state lighting due to their tunable colors, high conversion efficiency, and low cost. However, the performance of deep blue PeLEDs lags far behind that of near-infrared, red, and green ones. Here, the ligand concentration on the perovskite surface is regulated by introducing a small organic molecule 3-(5,9-dioxa-13b-boranaphtho [3,2,1-d,e] anthracene-7-yl)-9-phenyl-9H-carbazole (BOCzPh) to reduce the defects in the mixed-halogen perovskite lattice and improve the exciton binding energy of perovskite quantum dots (QDs). Finally, deep blue PeLEDs with an emission peak at 469 nm, a peak external quantum efficiency of 2.8%, and a maximum brightness of 851 cd m(-2) are obtained. Owing to the post-passivation of QDs by BOCzPh molecules, the emission spectra of the mixed-halide perovskites are stabilized and the luminous efficiency of the devices is improved simultaneously. This work provides a new approach to realize spectrally stable and efficient deep blue PeLEDs.

关键词