Broad-Temperature Optical Thermometry via Dual Sensitivity of Self-Trapped Excitons Lifetime and Higher-Order Phonon Anharmonicity in Lead-Free Perovskites

Guangming Niu; Jutao Jiang; Xiangyu Zeng; Xin Liu; Xiaowei Wang; Yutong Zhang; Li Che; Laizhi Sui; Guorong Wu; Kaijun Yuan; Xueming Yang

doi:10.1002/anie.202422424

Broad-Temperature Optical Thermometry via Dual Sensitivity of Self-Trapped Excitons Lifetime and Higher-Order Phonon Anharmonicity in Lead-Free Perovskites

Angew Chem Int Ed Engl. 2025 Jan 23:e202422424. doi: 10.1002/anie.202422424. Online ahead of print.

Authors

Guangming Niu¹, Jutao Jiang², Xiangyu Zeng³, Xin Liu¹, Xiaowei Wang³, Yutong Zhang¹, Li Che⁴, Laizhi Sui⁵, Guorong Wu³, Kaijun Yuan³, Xueming Yang³

Affiliations

¹ Dalian Maritime University, Marine Engineering College, CHINA.
² Ningbo University of Technology, School of New Energy, CHINA.
³ DICP: Chinese Academy of Sciences Dalian Institute of Chemical Physics, State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, CHINA.
⁴ Dalian Maritime University, Department of Physics, School of Science, CHINA.
⁵ Dalian Institute of Chemical Physics, State key Laboratory of Molecular Reaction Dynamics, 457 Zhongshan Road, 116023, Dalian, CHINA.

PMID: 39844778
DOI: 10.1002/anie.202422424

Abstract

Broad-temperature optical thermometry necessitates materials with exceptional sensitivity and stability across varied thermal conditions, presenting challenges for conventional systems. Here, we report a lead-free, vacancy-ordered perovskite Cs2TeCl6, that achieves precise temperature sensing through a novel combination of self-trapped excitons (STEs) photoluminescence (PL) lifetime modulation and unprecedented fifth-order phonon anharmonicity. The STEs PL lifetime demonstrates a highly temperature-sensitive response from 200 to 300 K, ideal for low-to-intermediate thermal sensing. In contrast, the Eg phonon mode undergoes significant linewidth broadening due to five-phonon scattering processes, with a distinct nonlinear temperature dependence up to 500 K. This fifth-order anharmonic effect enhances Raman-based temperature sensitivity, yielding a specific sensitivity (Sr) of 0.577% K-1 at 330 K and remaining above 0.5% K-1 at elevated temperatures. This study presents the first evidence of fifth-order anharmonic effects enhancing Raman-based temperature sensitivity, establishing Cs2TeCl6 as a versatile candidate for broad-temperature optical thermometry and opening new avenues for precise non-contact temperature sensing in advanced technological applications.

Keywords: Raman spectroscopy; anharmonic effects; lead-free perovskite; optical thermometry.