Efficient sky-blue perovskite light-emitting diodes via photoluminescence enhancement

• Published in: Nature communications Vol. 10; no. 1; pp. 5633 - 8
• Main Authors: Wang, Qi, Wang, Xiaoming, Yang, Zhi, Zhou, Ninghao, Deng, Yehao, Zhao, Jingjing, Xiao, Xun, Rudd, Peter, Moran, Andrew, Yan, Yanfa, Huang, Jinsong
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 10.12.2019; Nature Publishing Group; Nature Portfolio
• Subjects: 147/135; 147/136; 639/301/1005/1007; 639/4077/4072/4062; Diodes; Humanities and Social Sciences; Luminescence; multidisciplinary; Organic light emitting diodes; Perovskites; Photoluminescence; Photons; Science; Science & Technology - Other Topics; Science (multidisciplinary); Yttrium
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-13580-w

The efficiencies of green and red perovskite light-emitting diodes (PeLEDs) have been increased close to their theoretical upper limit, while the efficiency of blue PeLEDs is lagging far behind. Here we report enhancing the efficiency of sky-blue PeLEDs by overcoming a major hurdle of low photoluminescence quantum efficiency in wide-bandgap perovskites. Blending phenylethylammonium chloride into cesium lead halide perovskites yields a mixture of two-dimensional and three-dimensional perovskites, which enhances photoluminescence quantum efficiency from 1.1% to 19.8%. Adding yttrium (III) chloride into the mixture further enhances photoluminescence quantum efficiency to 49.7%. Yttrium is found to incorporate into the three-dimensional perovskite grain, while it is still rich at grain boundaries and surfaces. The yttrium on grain surface increases the bandgap of grain shell, which confines the charge carriers inside grains for efficient radiative recombination. Record efficiencies of 11.0% and 4.8% were obtained in sky-blue and blue PeLEDs, respectively. Despite the rapid progress on perovskite light emitting diodes (PeLEDs), the efficiency of blue PeLEDs is lagging behind. Here Wang et al. employ yttrium (III) chloride additive to yield enhanced photoluminescence in the perovskite materials and thus record high device efficiencies for sky-blue and blue PeLEDs.