Zhang Kai, Shen Yang, Cao Long-Xue, Su Zhen-Huang, Hu Xin-Mei, Feng Shi-Chi, Wang Bing-Feng, Xie Feng-Ming, Li Hao-Ze, Gao Xingyu, Li Yan-Qing, Tang Jian-Xin
Macao Institute of Materials Science and Engineering (MIMSE), Faculty of Innovation Engineering, Macau University of Science and Technology, Taipa, Macao, China.
Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, China.
Nat Commun. 2024 Dec 5;15(1):10621. doi: 10.1038/s41467-024-55074-4.
Blue perovskite light-emitting diodes (PeLEDs) still remain poorly developed due to the big challenge of achieving high-quality mixed-halide perovskites with wide optical bandgaps. Halide exchange is an effective scheme to tune the emission color of PeLEDs, while making perovskites susceptible to high defect density due to solvent erosion. Herein, we propose a versatile strategy for nondestructive in-situ halide exchange to obtain high-quality blue perovskites with low trap density and tunable bandgaps through long alkyl chain chloride incorporated chloroform post-treatment. In comparison with conventional halide exchange method, the ionic exchange mechanism of the present strategy is similar to a bimolecular nucleophilic substitution process, which simultaneously modulates perovskite bandgaps and inhibits new halogen vacancy generation. Consequently, efficient PeLEDs across blue spectral regions are obtained, exhibiting external quantum efficiencies of 23.6% (sky-blue emission at 488 nm), 20.9% (pure-blue emission at 478 nm), and 15.0% (deep-blue emission at 468 nm), respectively.
由于在实现具有宽带隙的高质量混合卤化物钙钛矿方面面临巨大挑战，蓝色钙钛矿发光二极管（PeLEDs）的发展仍然滞后。卤化物交换是一种调节PeLEDs发光颜色的有效方案，但由于溶剂侵蚀，会使钙钛矿容易出现高缺陷密度。在此，我们提出了一种通用的无损原位卤化物交换策略，通过长烷基链氯化物掺入氯仿后处理，获得具有低陷阱密度和可调带隙的高质量蓝色钙钛矿。与传统卤化物交换方法相比，本策略的离子交换机制类似于双分子亲核取代过程，该过程同时调节钙钛矿带隙并抑制新的卤素空位产生。因此，获得了跨越蓝色光谱区域的高效PeLEDs，其外量子效率分别为23.6%（488nm处天蓝色发射）、20.9%（478nm处纯蓝色发射）和15.0%（468nm处深蓝色发射）。
