Manipulation of Charge Dynamics for Efficient and Bright Blue Perovskite Light‐Emitting Diodes with Chiral Ligands
Lingjiao Zhang, Sujuan Hu, Min Guo, Yunfei Ren, Linfeng Wei, Wenxuan Li, Faxu Lin, Zhiyong Yang, Zhenyu Yang, Chuan Liu, Baiquan Liu
Abstract
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 −2 and a record power efficiency of 18.42 lm W −1 , rendering that the performance is among the best blue PeLEDs.