近日，南京工业大学的王建浦&黄维&朱琳及其研究团队取得一项新进展。经过不懈努力，他们实现用于高效钙钛矿LED的辐射复合加速。相关研究成果已于2024年5月29日在国际权威学术期刊《自然》上发表。

该研究团队提出了一种双添加剂结晶方法，可以形成高效的3D钙钛矿，实现了96%的卓越PLQE。这种方法促进了四角形FAPbI3钙钛矿的形成，以其高激子结合能而闻名，有效地加速了辐射复合。基于此，研究人员成功制备出具有创纪录峰值外量子效率（EQE）达32.0%的钙钛矿LED，即使在100mAcm^-2的高电流密度下，其效率依然保持在30.0%以上。这些重大突破为推进高效、高亮度钙钛矿LED的发展提供了有价值的见解。

据悉，平板显示器和固态照明应用对更高效、更亮的薄膜发光二极管(LED)的需求日益增长，这推动了对三维钙钛矿(3D)的研究。这些材料表现出高电荷迁移率和低量子效率下降，使它们成为实现具有增强亮度的高效LED的有希望的候选者。为了提高LED的效率，在促进辐射复合的同时尽量减少非辐射复合是至关重要的。各种钝化策略已被用于降低三维钙钛矿薄膜的缺陷密度，接近单晶的水平。然而，缓慢的辐射(双分子)复合限制了3D钙钛矿的光致发光量子效率(PLQEs)低于80%，导致LED器件的外部量子效率(EQEs)低于25%。

附：英文原文

Title: Acceleration of radiative recombination for efficient perovskite LEDs

Author: Li, Mengmeng, Yang, Yingguo, Kuang, Zhiyuan, Hao, Chenjie, Wang, Saixue, Lu, Feiyue, Liu, Zhongran, Liu, Jinglong, Zeng, Lingjiao, Cai, Yuxiao, Mao, Yulin, Guo, Jingshu, Tian, He, Xing, Guichuan, Cao, Yu, Ma, Chao, Wang, Nana, Peng, Qiming, Zhu, Lin, Huang, Wei, Wang, Jianpu

Issue&Volume: 2024-05-29

Abstract: The increasing demands for more efficient and brighter thin-film light-emitting diodes (LEDs) in flat-panel display and solid-state lighting applications have promoted research into three-dimensional (3D) perovskites. These materials exhibit high charge mobilities and low quantum efficiency droop, making them promising candidates for achieving efficient LEDs with enhanced brightness. To improve the efficiency of LEDs, it is crucial to minimize nonradiative recombination while promoting radiative recombination. Various passivation strategies have been used to reduce defect densities in 3D perovskite films, approaching levels close to those of single crystals. However, the slow radiative (bimolecular) recombination has limited the photoluminescence quantum efficiencies (PLQEs) of 3D perovskites to less than 80% , resulting in external quantum efficiencies (EQEs) of LED devices of less than 25%. Here we present a dual-additive crystallization method that enables the formation of highly efficient 3D perovskites, achieving an exceptional PLQE of 96%. This approach promotes the formation of tetragonal FAPbI₃ perovskite, known for its high exciton binding energy, which effectively accelerates the radiative recombination. As a result, we achieve perovskite LEDs with a record peak EQE of 32.0%, with the efficiency remaining greater than 30.0% even at a high current density of 100mAcm^-2. These findings provide valuable insights for advancing the development of high-efficiency and high-brightness perovskite LEDs.

DOI: 10.1038/s41586-024-07460-7

Source: https://www.nature.com/articles/s41586-024-07460-7