High‐Performance Perovskite Light‐Emitting Diode with Enhanced Operational Stability Using Lithium Halide Passivation. Issue 10 (29th January 2020)

• Record Type: Journal Article
• Authors: Wu, Tian; Li, Junnan; Zou, Yatao; Xu, Hao; Wen, Kaichuan; Wan, Shanshan; Bai, Sai; Song, Tao; McLeod, John A.; Duhm, Steffen; Gao, Feng; Sun, Baoquan
• Is Part Of: Angewandte Chemie international edition. Volume 59:Issue 10(2020)
• Page Start: 4099
• Page End: 4105
• Publication Date: 2020-01-29
• Subjects: lithium halides -- non-radiative recombination -- passivation -- stability -- surface defects; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201914000
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Defect passivation has been demonstrated to be effective in improving the radiative recombination of charge carriers in perovskites, and consequently, the device performance of the resultant perovskite light‐emitting diodes (LEDs). State‐of‐the‐art useful passivation agents in perovskite LEDs are mostly organic chelating molecules that, however, simultaneously sacrifice the charge‐transport properties and thermal stability of the resultant perovskite emissive layers, thereby deteriorating performance, and especially the operational stability of the devices. We demonstrate that lithium halides can efficiently passivate the defects generated by halide vacancies and reduce trap state density, thereby suppressing ion migration in perovskite films. Efficient green perovskite LEDs based on all‐inorganic CsPbBr3 perovskite with a peak external quantum efficiency of 16.2 %, as well as a high maximum brightness of 50 270 cd m −2, are achieved. Moreover, the device shows decent stability even under a brightness of 10 4 cd m −2 . We highlight the universal applicability of defect passivation using lithium halides, which enabled us to improve the efficiency of blue and red perovskite LEDs. Abstract : A green perovskite light‐emitting diode (LED) with both high efficiency and long‐term stability was fabricated through passivation effects of lithium bromide. The lithium bromide effectively passivates the surface defects, which leads to a high ratio of radiative recombination. Blue and red perovskite LEDs can also be fabricated by passivating with lithium halide (LiX). CB = conduction bond, VB = valence bond.