A new non-contact self-calibrated optical thermometer based on Ce3+ → Tb3+ → Eu3+ energy transfer process

Abstract

A new optical thermometry strategy based on the Ce3+ → Tb3+ → Eu3+ energy migration process has been proposed, which provides a promising approach to design non-contact self-calibrated optical thermometer with high temperature sensitivity and good signal discriminability. Specifically, uniform β-NaYF4:Ce3+/Tb3+/Eu3+ microcrystals have been successfully synthesized to explore its possible application in optical thermometry. Relying on different thermal responses between Ce3+ → Eu3+ metal-metal charge transfer (MMCT) and Ce3+ → Tb3+ → Eu3+ energy transfer process, the fluorescence intensity ratio (FIR) of Eu3+ to Tb3+ in the as-designed material presents excellent temperature sensing performance in the temperature range of 303–563 K. Using the as-synthesized β-NaYF4:Ce3+/Tb3+/Eu3+ phosphor as optical thermometric medium, the absolute and relative sensitivities can reach as high as 1.20% K−1 and 1.17% K−1, respectively. This study not only provides an effective approach for developing new optical temperature sensing materials, but also gives a reference for exploring other innovative optical thermometry.