Jiang Yuanzhi, Cui Minghuan, Li Saisai, Sun Changjiu, Huang Yanmin, Wei Junli, Zhang Li, Lv Mei, Qin Chaochao, Liu Yufang, Yuan Mingjian
Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Center (RECAST), College of Chemistry, Nankai University, 300071, Tianjin, P. R. China.
Henan Key Laboratory of Infrared Materials and Spectrum Measures and Applications, College of Physics and Materials Science, Henan Normal University, 453007, Xinxiang, P. R. China.
Nat Commun. 2021 Jan 12;12(1):336. doi: 10.1038/s41467-020-20555-9.
Rapid Auger recombination represents an important challenge faced by quasi-2D perovskites, which induces resulting perovskite light-emitting diodes' (PeLEDs) efficiency roll-off. In principle, Auger recombination rate is proportional to materials' exciton binding energy (E). Thus, Auger recombination can be suppressed by reducing the corresponding materials' E. Here, a polar molecule, p-fluorophenethylammonium, is employed to generate quasi-2D perovskites with reduced E. Recombination kinetics reveal the Auger recombination rate does decrease to one-order-of magnitude lower compared to its PEA analogues. After effective passivation, nonradiative recombination is greatly suppressed, which enables resulting films to exhibit outstanding photoluminescence quantum yields in a broad range of excitation density. We herein demonstrate the very efficient PeLEDs with a peak external quantum efficiency of 20.36%. More importantly, devices exhibit a record luminance of 82,480 cd m due to the suppressed efficiency roll-off, which represent one of the brightest visible PeLEDs yet.
快速俄歇复合是准二维钙钛矿面临的一项重要挑战，它会导致钙钛矿发光二极管（PeLEDs）的效率滚降。原则上，俄歇复合速率与材料的激子结合能（E）成正比。因此，可以通过降低相应材料的E来抑制俄歇复合。在此，使用极性分子对氟苯乙铵来制备具有降低的E的准二维钙钛矿。复合动力学表明，与基于苯乙胺（PEA）的类似物相比，俄歇复合速率确实降低到了一个数量级。经过有效的钝化后，非辐射复合得到了极大的抑制，这使得所得薄膜在很宽的激发密度范围内都表现出出色的光致发光量子产率。我们在此展示了峰值外量子效率为20.36%的非常高效的PeLEDs。更重要的是，由于效率滚降得到抑制，器件表现出创纪录的82480 cd m的亮度，这是目前最亮的可见PeLEDs之一。
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