Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
College of Materials Science and Opto-electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China.
Nat Commun. 2017 Jun 7;8:15640. doi: 10.1038/ncomms15640.
Inorganic perovskites such as CsPbX (X=Cl, Br, I) have attracted attention due to their excellent thermal stability and high photoluminescence quantum efficiency. However, the electroluminescence quantum efficiency of their light-emitting diodes was <1%. We posited that this low efficiency was a result of high leakage current caused by poor perovskite morphology, high non-radiative recombination at interfaces and perovskite grain boundaries, and also charge injection imbalance. Here, we incorporated a small amount of methylammonium organic cation into the CsPbBr lattice and by depositing a hydrophilic and insulating polyvinyl pyrrolidine polymer atop the ZnO electron-injection layer to overcome these issues. As a result, we obtained light-emitting diodes exhibiting a high brightness of 91,000 cd m and a high external quantum efficiency of 10.4% using a mixed-cation perovskite CsMAPbBr as the emitting layer. To the best of our knowledge, this is the brightest and most-efficient green perovskite light-emitting diodes reported to date.
无机钙钛矿如 CsPbX（X=Cl、Br、I）因其优异的热稳定性和高光致发光量子效率而受到关注。然而，它们的发光二极管的电致发光量子效率<1%。我们假设这种低效率是由于钙钛矿形态不佳导致的漏电流高、界面和钙钛矿晶粒边界处的非辐射复合率高以及电荷注入不平衡造成的。在这里，我们将少量的甲脒有机阳离子掺入 CsPbBr 晶格中，并在 ZnO 电子注入层上沉积一层亲水性和绝缘性的聚乙烯基吡咯烷酮聚合物，以克服这些问题。结果，我们使用混合阳离子钙钛矿 CsMAPbBr 作为发射层，获得了亮度为 91,000cd/m²、外量子效率为 10.4%的高亮度发光二极管。据我们所知，这是迄今为止报道的最亮、效率最高的绿色钙钛矿发光二极管。
