Advancing luminescence thermometry: Employing multiple fluorescence intensity ratios of YAG:Er3+/Mn4+ nanocrystals for supersensitive temperature sensing

Luminescence thermometry has gained significant attention for its semi-invasive and highly accurate temperature sensing capabilities. Recent research has focused on improving sensitivity, particularly using the Luminescence Intensity Ratio (LIR) technique. This study advances luminescence thermometry by employing the LIR technique with Er 3+ and Mn 4+ ions in a Y 3 Al 5 O 12 host. By combining the temperature-insensitive emission of Er 3+ ( 4 S 3/2 ) and the temperature-sensitive emission of Mn 4+ ( 2 E) over the 200–450 K range, we achieve a relative sensitivity of 6.4 %K -1 at room temperature. Additionally, we introduce a novel approach by utilizing the higher energy Er 3+ 2 H 11/2 level, which thermalizes with the 4 S 3/2 level, further enhancing sensitivity. This dual LIR method, leveraging both thermally activated Er 3+ and rapidly quenching Mn 4+ emissions, yields an impressive sensitivity of 8 %K -1 at 300 K- one of the highest reported. Temperature resolutions at 350 K for the LIRs of 4 S 3/2 Er 3+ / 2 E Mn 4+ , and 2 H 11/2 Er 3+ / 2 E Mn 4+ emissions are estimated to be 0.48 K and 0.59 K, respectively. Finally, we demonstrate the potential of this material for highly sensitive temperature mapping, utilizing cameras with RAW image capabilities that allow separate analysis of RGB channels.