Rearranging Low-Dimensional Phase Distribution of Quasi-2D Perovskites for Efficient Sky-Blue Perovskite Light-Emitting Diodes

作者：Pang, Peiyuan; Jin, Guangrong; Liang, Chao; Wang, Bingzhe; Xiang, Wei; Zhang, Dengliang; Xu, Jingwei; Hong, Wei; Xiao, Zewen; Wang, Lei; Xing, Guichuan^*; Chen, Jiangshan^*; Ma, Dongge^*

来源：ACS Nano, 2020, 14(9): 11420-11430.

DOI：10.1021/acsnano.0c03765

• quasi-2D perovskite
• phase distribution
• light-emitting diode
• sky-blue
• sodium ion

Metal halide perovskites have received much attention for their application in light-emitting diodes (LEDs) in the past several years. Rapid progress has been made in efficient green, red, and near-infrared perovskite LEDs. However, the development of blue perovskite LEDs is still lagging far behind. Here, we report efficient sky-blue perovskite LEDs by rearranging low-dimensional phase distribution in quasi-2D perovskites. We incorporated sodium ions into the mixed-Cl/Br quasi-2D perovskites with phenylethylammonium as the organic spacer and cesium lead halide as the inorganic framework. The inclusion of the sodium ion was found to significantly reduce the formation of the n = 1 phase, which was dominated by nonradiative transition, and increase the formation of other small-n phases for efficient exciton energy transfer. By managing the phase distribution, a maximum external quantum efficiency (EQE) of 11.7% was achieved in the sky-blue perovskite LED, with a stable emission peak at 488 nm. Further optimizing the phase distribution and film morphology with Pb content, we demonstrated the sky-blue devices with the average EQE approaching 10%. This strategy of engineering phase distribution of quasi-2D perovskites with a sodium ion could provide a useful way for the fabrication of high-performance blue perovskite LEDs.

• 单位
  华中科技大学