Luminescent enhancement and multi-mode optical thermometry of erbium doped halide Cs2(Na/Ag)BiCl6 microcrystals*

Lanthanum-doped double halide perovskite has attracted increasing interest due to its distinctive upconversion and near-infrared (NIR) luminous characteristics. Here, erbium ion (Er3+) doped Cs2(Na/Ag) BiCl6 microcrystals (MCs) were synthesized and proved to be one of the most prospective candidates for optical thermometry. The enhancement of both white light from self-trapped exciton emission and NIR emission from Er3+ ion of Cs2AgBiCl6 microcrystals is caused by lattice distortion due to Na+ ion doping. Fluorescence intensity ratio and lifetime methods provide self-referenced and sensitive thermometry under 405 and/or 980 nm laser excitation at the temperatures from 80 to 480 K. Besides, the maximum values of relative and absolute sensitivity of 3.62%/K and 27%/K can be achieved in the low to high temperature range under 980 and 405 nm laser co-excitation. Through the experimental analysis, Er3+ doped Cs2(Na/Ag)BiCl6 double perovskite is considered to be an ideal self-calibrating thermometric material due to its good long-term stability and multi-mode function of excitation and detection. (c) 2024 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.