Er3+-doped BaY2F8 for non-contact lifetime thermometry: Combined effects of dopant concentration and programmable UV LED excitation

Abstract

This work presents a luminescence thermometry system based on a programmable electronic module designed for precise control of excitation pulses using a UV LED source, enabling time-resolved measurements of luminescence lifetime. This system was applied to investigate the influence of dopant concentration on the luminescence lifetime of Er³⁺ ions in a barium and yttrium fluoride matrix (BaY₂F₈) doped with different concentrations (1, 2, and 3 mol%) and their possible effects on thermometric usage. Spectroscopic measurements revealed that the sample with 3 mol% of Er³⁺ exhibited the highest luminescence efficiency, without evidence of concentration quenching. The luminescence lifetime decreased with increasing temperature, which was attributed to the increase in nonradiative de-excitation processes observed for all samples. The relative thermal sensitivity (S_r) was obtained from the lifetime dependence on temperature with the 3 mol% Er³⁺-doped sample presenting the highest S_r, reaching 0.36 % K⁻¹ at 317 K, indicating its potential usage as a non-contact luminescent thermometer. The measurements were performed via an electronic module specifically developed for excitation and lifetime-based luminescence detection, allowing precise control of the excitation pulse parameters. The repeatability of the measurements reached approximately 98 %, confirming that the sensor is stable and highly reproducible. The results demonstrate that lifetime-based luminescence thermometry using Er³⁺-doped BaY₂F₈, combined with a programmable electronic module for precise excitation and detection control, provides a robust and accessible approach for temperature sensing, reducing the dependence on complex excitation sources, such as lasers, and increasing flexibility in data acquisition.