Development of sensor materials for fluorescence thermometer application using LED excitation

Phosphor materials, such as Cr doped spinel (MgAl₂O_4|), garnet (Y{ub3}Al₅O₁₂) and sapphire (Al₂O₃) crystals and composites of these materials are developed for a highly sensitive thermo-sensor in fluorescence thermometer excited using LED. Temperature dependences of photoluminescence (PL) intensity from these materials are evaluated using LED excitation. PL intensity from sensor materials decreases linearly with temperature. Impurities doped sapphire, spinel, garnet crystals and their composites are found to be suitable materials as sensor materials for fluorescence thermometer using LED excitation. Yellow colored LED is found to be useful excitation light for Cr doped sensor materials. All the materials examined in this paper can be effectively excited using a yellow colored LED.