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

• Published in: ACS nano Vol. 14; no. 9; pp. 11420 - 11430
• Main Authors: 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
• Format: Journal Article
• Language: English
• Published: American Chemical Society 22.09.2020
• Subjects: quasi-2D perovskite; sky-blue; light-emitting diode; sodium ion; phase distribution
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/acsnano.0c03765

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.