Cui Jieyuan, Liu Yang, Deng Yunzhou, Lin Chen, Fang Zhishan, Xiang Chensheng, Bai Peng, Du Kai, Zuo Xiaobing, Wen Kaichuan, Gong Shaolong, He Haiping, Ye Zhizhen, Gao Yunan, Tian He, Zhao Baodan, Wang Jianpu, Jin Yizheng
Zhejiang Key Laboratory for Excited-State Materials, State Key Laboratory of Silicon Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
Zhejiang Key Laboratory for Excited-State Materials, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
Sci Adv. 2021 Oct 8;7(41):eabg8458. doi: 10.1126/sciadv.abg8458.
Solution-processed planar perovskite light-emitting diodes (LEDs) promise high-performance and cost-effective electroluminescent devices ideal for large-area display and lighting applications. Exploiting emission layers with high ratios of horizontal transition dipole moments (TDMs) is expected to boost the photon outcoupling of planar LEDs. However, LEDs based on anisotropic perovskite nanoemitters remain to be inefficient (external quantum efficiency, EQE <5%) due to the difficulties of simultaneously controlling the orientations of TDMs, achieving high photoluminescence quantum yields (PLQYs) and realizing charge balance in the films of assembled nanostructures. Here, we demonstrate efficient electroluminescence from an in situ grown perovskite film composed of a monolayer of face-on oriented nanoplatelets. The ratio of horizontal TDMs of the perovskite nanoplatelet film is 84%, which leads to a light-outcoupling efficiency of ~31%, substantially higher than that of isotropic emitters (23%). In consequence, LEDs with a peak EQE of 23.6% are achieved, representing highly efficient planar perovskite LEDs.
溶液法制备的平面钙钛矿发光二极管（LED）有望成为适用于大面积显示和照明应用的高性能、低成本电致发光器件。利用具有高比例水平跃迁偶极矩（TDM）的发光层有望提高平面LED的光子出射效率。然而，基于各向异性钙钛矿纳米发光体的LED效率仍然较低（外量子效率，EQE<5%），这是因为同时控制TDM的取向、实现高光致发光量子产率（PLQY）以及在组装纳米结构薄膜中实现电荷平衡存在困难。在此，我们展示了由单层面朝上取向的纳米片组成的原位生长钙钛矿薄膜的高效电致发光。钙钛矿纳米片薄膜的水平TDM比例约为84%，这导致光出射耦合效率约为31%，大大高于各向同性发光体（约23%）。因此，实现了峰值EQE为23.6%的LED，代表了高效的平面钙钛矿LED。
