Dimension control of in situ fabricated CsPbClBr2 nanocrystal films toward efficient blue light-emitting diodes

• Published in: Nature communications Vol. 11; no. 1; pp. 6428 - 8
• Main Authors: Wang, Chenhui, Han, Dengbao, Wang, Junhui, Yang, Yingguo, Liu, Xinyue, Huang, Sheng, Zhang, Xin, Chang, Shuai, Wu, Kaifeng, Zhong, Haizheng
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 22.12.2020; Nature Publishing Group; Nature Portfolio
• Subjects: 140/125; 639/301/1005; 639/301/357; Domains; Electroluminescence; Fabrication; Halides; Humanities and Social Sciences; Ligands; Light emitting diodes; Luminescence; multidisciplinary; Nanocrystals; Perovskites; Photoluminescence; Photons; Quantum efficiency; Quantum wells; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-20163-7

In the field of perovskite light-emitting diodes (PeLEDs), the performance of blue emissive electroluminescence devices lags behind the other counterparts due to the lack of fabrication methodology. Herein, we demonstrate the in situ fabrication of CsPbClBr 2 nanocrystal films by using mixed ligands of 2-phenylethanamine bromide (PEABr) and 3,3-diphenylpropylamine bromide (DPPABr). PEABr dominates the formation of quasi-two-dimensional perovskites with small- n domains, while DPPABr induces the formation of large- n domains. Strong blue emission at 470 nm with a photoluminescence quantum yield up to 60% was obtained by mixing the two ligands due to the formation of a narrower quantum-well width distribution. Based on such films, efficient blue PeLEDs with a maximum external quantum efficiency of 8.8% were achieved at 473 nm. Furthermore, we illustrate that the use of dual-ligand with respective tendency of forming small- n and large- n domains is a versatile strategy to achieve narrow quantum-well width distribution for photoluminescence enhancement. Designing efficient blue perovskite LEDs by using mixed halides perovskite is still a challenge, limited mainly by the phase segregation issue. Here, the authors demonstrate in situ fabrication of quasi-2D CsPbClBr2 nanocrystal films with mixed ligands to overcome the constraint.