Efficient and Spectrally Stable Blue Perovskite Light-Emitting Diodes Based on Potassium Passivated Nanocrystals
Efficient and Spectrally Stable Blue Perovskite Light-Emitting Diodes Based on Potassium Passivated Nanocrystals
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DOI：
10.1002/adfm.201908760
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发表时间：
2020-01-20
影响因子：
19
通讯作者：
Wang, Lei
中科院分区：
文献类型：
--
作者：
Yang, Fei;Chen, Hongting;Wang, Lei
金属卤化物钙钛矿材料在显示和照明领域具有广阔的应用前景，近年来引起了人们极大的兴趣。然而，由于难以获得高质量的蓝色钙钛矿发光层，蓝色钙钛矿发光二极管（PeLED）的发展仍然远远落后于其绿色和红色表亲。在这项研究中，设想了一种简单的方法来改善蓝色钙钛矿的发射和电学性能。通过引入碱金属离子占据外围悬浮有机配体的某些位置，抑制了非辐射复合，从而获得了具有38.4%的高光致发光量子效率的蓝色CsPb（Br/Cl）（3）纳米晶体。引入的K+作为一种新型的金属配体，不仅抑制了非辐射途径，而且改善了钙钛矿纳米晶体的载流子输运。通过进一步设计器件结构以平衡电荷注入速率，制造了在477 nm的发射峰处具有1.96%的最大外量子效率的光谱稳定且高效的蓝色PeLED。
Metal halide perovskites have aroused tremendous interest in the past several years for their promising applications in display and lighting. However, the development of blue perovskite light-emitting diodes (PeLEDs) still lags far behind that of their green and red cousins due to the difficulty in obtaining high-quality blue perovskite emissive layers. In this study, a simple approach is conceived to improve the emission and electrical properties of blue perovskites. By introducing an alkali metal ion to occupy some sites of peripheral suspended organic ligands, the nonradiative recombination is suppressed, and, consequently, blue CsPb(Br/Cl)(3) nanocrystals with a high photoluminescence quantum efficiency of 38.4% are obtained. The introduced K+ acts as a new type of metal ligand, which not only suppresses nonradiative pathways but also improves the charge carrier transport of the perovskite nanocrystals. With further engineering of the device structure to balance the charge injection rate, a spectrally stable and efficient blue PeLED with a maximum external quantum efficiency of 1.96% at the emission peak of 477 nm is fabricated.