Song Li, Guo Xiaoyang, Hu Yongsheng, Lv Ying, Lin Jie, Liu Zheqin, Fan Yi, Liu Xingyuan
State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences , Changchun 130033, China.
University of Chinese Academy of Sciences , Beijing 100049, China.
J Phys Chem Lett. 2017 Sep 7;8(17):4148-4154. doi: 10.1021/acs.jpclett.7b01733. Epub 2017 Aug 21.
Efficient inorganic perovskite light-emitting diodes (PeLEDs) with an ultrathin perovskite emission layer (∼30 nm) were realized by doping Lewis base polyethylene glycol (PEG) into CsPbBr films. PEG in the perovskite films not only physically fills the crystal boundaries but also interacts with the perovskite crystals to passivate the crystal grains, reduce nonradiative recombination, and ensure efficient luminance and high efficiency. As a result, promoted brightness, current efficiency (CE), and external quantum efficiency (EQE) were achieved. The nonradiative decay rate of the PEG:CsPbBr composite film is 1 order of magnitude less than that of the neat CsPbBr film. After further optimization of the molar ratio between CsBr and PbBr, a peak CE of 19 cd/A, a maximum EQE of 5.34%, and a maximum brightness of 36600 cd/m were achieved, demonstrating the interaction between PEG and the precursors. The results are expected to offer some helpful implications in optimizing the polymer-assisted PeLEDs with ultrathin emission layers, which might have potential application in see-through displays.
通过将路易斯碱聚乙二醇（PEG）掺杂到CsPbBr薄膜中，实现了具有超薄钙钛矿发光层（约30 nm）的高效无机钙钛矿发光二极管（PeLED）。钙钛矿薄膜中的PEG不仅物理填充晶界，还与钙钛矿晶体相互作用，以钝化晶粒、减少非辐射复合，并确保高效发光和高效率。结果，实现了亮度、电流效率（CE）和外量子效率（EQE）的提高。PEG:CsPbBr复合薄膜的非辐射衰减率比纯CsPbBr薄膜低1个数量级。在进一步优化CsBr与PbBr之间的摩尔比后，实现了19 cd/A的峰值CE、5.34%的最大EQE和36600 cd/m的最大亮度，证明了PEG与前驱体之间的相互作用。这些结果有望为优化具有超薄发光层的聚合物辅助PeLED提供一些有益的启示，其可能在透明显示器中具有潜在应用。
