Synergistic function of doping and ligand engineering to enhance the photostability and electroluminescence performance of CsPbBr3quantum dots

Junfei Chen; Zhaohui Shen; Pengbo Liu; Zhengyang Sun; Jay Guoxu Liu; Chongyu Shen; Dandan Song; Suling Zhao; Zheng Xu

doi:10.1088/1361-6528/abfc73

Synergistic function of doping and ligand engineering to enhance the photostability and electroluminescence performance of CsPbBr₃quantum dots

Nanotechnology. 2021 May 17;32(32). doi: 10.1088/1361-6528/abfc73.

Authors

Junfei Chen^{1

2}, Zhaohui Shen^{1

2}, Pengbo Liu^{1

2}, Zhengyang Sun^{1

2}, Jay Guoxu Liu³, Chongyu Shen³, Dandan Song^{1

2}, Suling Zhao^{1

2}, Zheng Xu^{1

2}

Affiliations

¹ Key Laboratory of Luminescence and Optical Information, Beijing Jiaotong University, Ministry of Education, Beijing 100044, People's Republic of China.
² Institute of Optoelectronics Technology, Beijing Jiaotong University, Beijing 100044, People's Republic of China.
³ ShineOn (Beijing) Technology Co., Ltd, Beijing 100176, People's Republic of China.

PMID: 33910184
DOI: 10.1088/1361-6528/abfc73

Abstract

The photostability issue of CsPbX₃(X = Cl, Br, I) quantum dots (QDs) is one of the key origins for the degradation of their luminescence performance, which hinders their application in lighting and displays. Herein, we report a new method combining doping and ligand engineering, which effectively improves the photostability of CsPbBr₃QDs and the performance of QD light-emitting diodes (QLEDs). In this method, ZnBr₂is doped into CsPbBr₃QDs to reduce surface anion defects; didodecyldimethyl ammonium bromide (DDAB) and tetraoctylammonium bromide (TOAB) hybrid ligands, which have strong adsorption with QDs, are employed to protect the surface and enhance the conductivity of QD layer in QLEDs. The photoluminescence (PL) and transmission electron microscopy measurements prove the effectively improved photostability of CsPbX₃QDs. Moreover, reduced defects and improved conductivity by doping and hybrid ligands treatment also enable the improved electroluminescence performance of CsPbX₃QDs. The maximum luminance and external quantum efficiency of the QLED with optimized CsPbX₃QDs are 3518.9 cd m^-2and 5.07%, which are 3.6 and 2.1 times than that of the control device, respectively. Combining doping and hybrid ligands makes perovskite QDs have an extremely promising prospect in future applications of high-definition displays, high-quality lighting, as well as solar cells.

Keywords: CsPbBr3 perovskite; electroluminescence; ligand engineering; light-emitting diodes; photostability; quantum dots.