High-sensitivity temperature sensor of Cr3+-doped Lu2BaAl4SiO12 phosphor

During recent years, non-contact ratiometric luminescent thermometry has gained increasing attention in scientific research due to its remarkable advantages including high precision, rapid response, and operational convenience. Chromium ions (Cr 3+ ), owing to their high emission intensity and inherent benefits from the 3d 3 electronic configuration, have emerged as the most extensively utilized transition metal ions in luminescent temperature sensing. Accordingly, we synthesized Lu 2 BaAl 4 SiO 12 :Cr 3+ phosphors via high-temperature solid-state reaction and systematically investigated their photoluminescence-based temperature sensitivity. In this material, Cr 3+ ions experience strong crystal field effects, resulting in the observation of both R-line emissions and narrowband emissions from the overlapping 2 E and 4 T 2 transitions. By strategically employing the fluorescence intensity ratio (FIR) between these emissions, we developed a ratiometric luminescent thermometer achieving a maximum relative sensitivity ( S r ) of 1.93%/K at 498 K. Furthermore, an optical temperature-sensing film was fabricated for practical temperature measurements in organic solutions. The results demonstrate excellent agreement between FIR-derived temperatures and programmed values, with a maximum deviation of merely 1.49 K. These findings establish a novel approach for designing highly sensitive Cr 3+ -doped ratiometric fluorescent temperature sensors.