Sn2+/Mn2+ codoped strontium phosphate (Sr2P2O7) phosphor for high temperature optical thermometry

In this work, a new type of luminescent temperature sensor based on the Sn 2+ →Mn 2+ resonance energy transfer is designed, which shows great potential in high temperature optical thermometry. Using the micro-sized Sn 2+ /Mn 2+ :α-Sr 2 P 2 O 7 phosphor fabricated by carbon reduction method as optical thermometer, the sensitivity in the temperature range of 423 K–623 K is well superior to that for the other micro/nano luminescent temperature sensing materials reported previously, and the maximal absolute sensitivity reaches as high as 0.027 K −1  at 623 K. Analyses of the temperature-dependent photoluminescence spectra and configurational coordinate diagrams for Sn 2+ :α-Sr 2 P 2 O 7 and Mn 2+ :α-Sr 2 P 2 O 7 indicate that the temperature-sensitive variation in fluorescence intensity ratio of Sn 2+ to Mn 2+ is originated from the difference in thermal quenching activation energy for 3 P J (J = 0,1) levels of Sn 2+ (4053 cm −1 ) and 4 T 1 level of Mn 2+ (2464 cm −1 ). These results may provide useful inspiration for building highly sensitive self-referencing optical thermometers based on energy transfer induced sensitized luminescence.