Enhancing crystal integrity and structural rigidity of CsPbBr3 nanoplatelets to achieve a narrow color-saturated blue emission

Qianqian Huang; Wenxu Yin; Bo Gao; Qingsen Zeng; Dong Yao; Hao Zhang; Yinghe Zhao; Weijia Zheng; Jiaqi Zhang; Xuyong Yang; Xiaoyu Zhang; Andrey L Rogach

doi:10.1038/s41377-024-01441-1

Enhancing crystal integrity and structural rigidity of CsPbBr₃ nanoplatelets to achieve a narrow color-saturated blue emission

Light Sci Appl. 2024 May 11;13(1):111. doi: 10.1038/s41377-024-01441-1.

Authors

Qianqian Huang^#¹, Wenxu Yin^#¹, Bo Gao¹, Qingsen Zeng², Dong Yao², Hao Zhang², Yinghe Zhao³, Weijia Zheng⁴, Jiaqi Zhang¹, Xuyong Yang⁵, Xiaoyu Zhang⁶, Andrey L Rogach⁷

Affiliations

¹ Key Laboratory of Automobile Materials MOE, School of Materials Science & Engineering, and Jilin Provincial International Cooperation Key Laboratory of High-Efficiency Clean Energy Materials, Jilin University, Changchun, China.
² State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, China.
³ State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, China.
⁴ Department of Chemistry, University of Victoria, Victoria, BC, Canada. alex610@foxmail.com.
⁵ Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, Shanghai, China.
⁶ Key Laboratory of Automobile Materials MOE, School of Materials Science & Engineering, and Jilin Provincial International Cooperation Key Laboratory of High-Efficiency Clean Energy Materials, Jilin University, Changchun, China. zhangxiaoyu@jlu.edu.cn.
⁷ Department of Materials Science and Engineering, and Centre for Functional Photonics (CFP), City University of Hong Kong, Hong Kong S.A.R, China. andrey.rogach@cityu.edu.hk.

^# Contributed equally.

Abstract

Quantum-confined CsPbBr₃ perovskites are promising blue emitters for ultra-high-definition displays, but their soft lattice caused by highly ionic nature has a limited stability. Here, we endow CsPbBr₃ nanoplatelets (NPLs) with atomic crystal-like structural rigidity through proper surface engineering, by using strongly bound N-dodecylbenzene sulfonic acid (DBSA). A stable, rigid crystal structure, as well as uniform, orderly-arranged surface of these NPLs is achieved by optimizing intermediate reaction stage, by switching from molecular clusters to mono-octahedra, while interaction with DBSA resulted in formation of a Cs_xO monolayer shell capping the NPL surface. As a result, both structural and optical stability of the CsPbBr₃ NPLs is enhanced by strong covalent bonding of DBSA, which inhibits undesired phase transitions and decomposition of the perovskite phase potentially caused by ligand desorption. Moreover, rather small amount of DBSA ligands at the NPL surface results in a short inter-NPL spacing in their closely-packed films, which facilitates efficient charge injection and transport. Blue photoluminescence of the produced CsPbBr₃ NPLs is bright (nearly unity emission quantum yield) and peaks at 457 nm with an extremely narrow bandwidth of 3.7 nm at 80 K, while the bandwidth of the electroluminescence (peaked at 460 nm) also reaches a record-narrow value of 15 nm at room temperature. This value corresponds to the CIE coordinates of (0.141, 0.062), which meets Rec. 2020 standards for ultra-high-definition displays.