Manipulation of Charge Dynamics for Efficient and Bright Blue Perovskite Light-Emitting Diodes with Chiral Ligands.

Zhang, Lingjiao; Hu, Sujuan; Guo, Min; Ren, Yunfei; Wei, Linfeng; Li, Wenxuan; Lin, Faxu; Yang, Zhiyong et al. · Adv Mater · 2023

basic_science · Level V

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Abstract

Perovskite light-emitting diodes (PeLEDs) emerge as a promising class of optoelectronic devices for next-generation displays and lighting technology. However, the performance of blue PeLEDs lags far behind that of their green and red counterparts, including the unachieved trade-off between high efficiency and high luminance, severe efficiency roll-off, and unsatisfactory power efficiency. Here, a multi-functional chiral ligand of L-phenylalanine methyl ester hydrochloride is strategically introduced into quasi-2D perovskites, which can effectively passivate defects, modulate the phase distribution, improve photoluminescence quantum yield, guarantee high-quality film morphology, and enhance charge transport. Furthermore, ladder-like hole transport layers are established, boosting charge injection and balance. The resultant sky-blue PeLEDs (the photoluminescence peak is 493 nm and the electroluminescence peak is 497 nm) exhibit an external quantum efficiency of 12.43% at 1000 cd m<sup>-2</sup> and a record power efficiency of 18.42 lm W<sup>-1</sup> , rendering that the performance is among the best blue PeLEDs.