CsPbBr3-Cs4PbBr6 composite nanocrystals for highly efficient pure green light emission

Miao He; Chunyun Wang; Jingzhou Li; Jiang Wu; Siwei Zhang; Hao-Chung Kuo; Liyang Shao; Shichao Zhao; Jinzhong Zhang; Feiyu Kang; Guodan Wei

doi:10.1039/c9nr07096f

CsPbBr₃-Cs₄PbBr₆ composite nanocrystals for highly efficient pure green light emission

Nanoscale. 2019 Dec 21;11(47):22899-22906. doi: 10.1039/c9nr07096f. Epub 2019 Nov 25.

Authors

Miao He¹, Chunyun Wang², Jingzhou Li², Jiang Wu², Siwei Zhang², Hao-Chung Kuo³, Liyang Shao⁴, Shichao Zhao⁵, Jinzhong Zhang¹, Feiyu Kang², Guodan Wei²

Affiliations

¹ Key Laboratory of Polar Materials and Devices (MOE) and Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Department of Electronic Engineering, East China Normal University, Shanghai 200241, China. jzzhang@ee.ecnu.edu.cn.
² Tsinghua-Berkeley Shenzhen Institute (TBSI), Tsinghua University, Shenzhen, 518055, China and Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China. weiguodan@sz.tsinghua.edu.cn.
³ Department of Electrical Engineering and Computer Sciences and Tsinghua-Berkeley Shenzhen Institute (TBSI), University of California at Berkeley, Berkeley, California 94720, USA.
⁴ Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
⁵ College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou, 310018, China.

PMID: 31763640
DOI: 10.1039/c9nr07096f

Abstract

All-inorganic perovskite CsPbBr₃-Cs₄PbBr₆ composite nanocrystals (NCs) were synthesized via a convenient solution process without inert gas protection and systematically studied as green phosphors for light emitting diode (LED) applications. While colloidal composite NCs emit green color with an emission peak at around 515 nm, their thin films on top of blue GaN chips exhibit a redshift of ∼15-20 nm due to subsequential aggregation in solid state. The Commission Internationale De I'eclairage (CIE) chromaticity coordinates of the green LEDs assembled by composite NCs reached (0.201, 0.746) with nearly 100% green ratio. Moreover, the pure green LED displayed a luminous efficiency of 45 lm W^-1 under 10 mA driving current. The colloidal CsPbBr₃-Cs₄PbBr₆ composite NCs have the photoluminescence quantum yield (PLQY) as high as 74%. The high PLQY originates from cubic CsPbBr₃ NCs well passivated by the zero-dimensional Cs₄PbBr₆ matrix, substantially suppressing the nonradiative recombination. The comparison between the green LEDs fabricated with pure and composite perovskites imply that the CsPbBr₃-Cs₄PbBr₆ composites with higher quantum yield could be an effective way to get the brightness and the stability of pure green LEDs.