Unravelling Alkali‐Metal‐Assisted Domain Distribution of Quasi‐2D Perovskites for Cascade Energy Transfer toward Efficient Blue Light‐Emitting Diodes

Autor: Wanqing Cai, Muhammad Umair Ali, Ping Liu, Miao He, Cong Zhao, Ziming Chen, Yue Zang, Man‐Chung Tang, Hong Meng, Hongyan Fu, Guodan Wei, Hin‐Lap Yip
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Advanced Science, Vol 9, Iss 20, Pp n/a-n/a (2022)
Druh dokumentu: article
ISSN: 2198-3844
DOI: 10.1002/advs.202200393
Popis: Abstract Solution processable quasi‐2D (Q‐2D) perovskite materials are emerging as a promising candidate for blue light source in full‐color display applications due to their good color saturation property, high brightness, and spectral tunability. Herein, an efficient energy cascade channel is developed by introducing sodium bromide (NaBr) in phenyl‐butylammonium (PBA)‐containing mixed‐halide Q‐2D perovskites for a blue perovskite light‐emitting diode (PeLED). The incorporation of alkali metal contributes to the nucleation and growth of Q‐2D perovskites into graded distribution of domains with different layer number . The study of excitation dynamics by transient absorption (TA) spectroscopy confirms that NaBr induces more Q‐2D perovskite phases with small n number, providing a graded energy cascade pathway to facilitate more efficient energy transfer processes. In addition, the nonradiative recombination within the Q‐2D perovskites is significantly suppressed upon Na+ incorporation, as validated by the trap density estimation. Consequently, the optimized blue PeLEDs manifest a peak external quantum efficiency (EQE) of 7.0% emitting at 486 nm with a maximum luminance of 1699 cd m−2. It is anticipated that these findings will improve the understanding of alkali‐metal‐assisted optimization of Q‐2D perovskites and pave the way toward high‐performance blue PeLEDs.
Databáze: Directory of Open Access Journals
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