Facile Melting-Crystallization Synthesis of Cs2NaxAg1- xInCl6: Bi Double Perovskites for White Light-Emitting Diodes

Xiaoxi Li; Weiwei Li; Mengling Xia; Chao Liu; Neng Li; Zuhao Shi; Yinsheng Xu; Xianghua Zhang

doi:10.1021/acs.inorgchem.1c03996

Facile Melting-Crystallization Synthesis of Cs₂Na_xAg_{1- x}InCl₆: Bi Double Perovskites for White Light-Emitting Diodes

Inorg Chem. 2022 Mar 28;61(12):5040-5047. doi: 10.1021/acs.inorgchem.1c03996. Epub 2022 Mar 11.

Authors

Xiaoxi Li¹, Weiwei Li², Mengling Xia³, Chao Liu¹, Neng Li¹, Zuhao Shi¹, Yinsheng Xu¹, Xianghua Zhang^{1

4}

Affiliations

¹ State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, China.
² State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China.
³ Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430074, China.
⁴ ISCR (Institut Des Sciences Chimiques de Rennes)-UMR 6226, CNRS, Univ Rennes, 35000 Rennes, France.

PMID: 35275617
DOI: 10.1021/acs.inorgchem.1c03996

Abstract

Lead-free double perovskites (DPs) have outstanding luminescent properties, which make them excellent candidates for wide use in optoelectronics. Herein, a solvent-free melting-crystallization technique, which can produce kilogram-scale DP microcrystals (DP-MCs) in one batch, is invented to synthesize the Cs₂Na_xAg_1-xInCl₆: Bi (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) DP-MCs. The structure and composition analysis confirmed the products are pure Cs₂Na_xAg_1-xInCl₆ DP-MCs. Affected by Jahn-Teller distortion of AgCl₆ octahedra, self-trapped excitons appear in the excited state, resulting in the broadband emission (400-850 nm) of Cs₂Ag_1-xNa_xInCl₆: Bi DP-MCs. The enhancement of the photoluminescence quantum yield can be realized by introducing Na⁺ to break the parity-forbidden transition in the Cs₂AgInCl₆ DP. Optimized Cs₂Na_0.4Ag_0.6InCl₆: Bi DP-MC phosphors combined with commercial blue and green phosphors were coated on ultraviolet chips (365 nm) to fabricate white light-emitting diodes (WLEDs) from warm white (2930 K) to cold white (6957 K). An ultrahigh color rendering index of 97.1 and a CCT of 5548 K as well as Commission Internationale de l'Eclairage color coordinates of (0.331, 0.339) have been demonstrated. This kilogram-scale synthesis technique could stimulate the industrial development of WLEDs for general lighting based on DP-MC phosphors.