Novel GdAlGe2O7:Bi3+,Eu3+ phosphors with anti-thermal quenching properties for high sensitivity optical temperature measurement

The thermometry technique based on fluorescence intensity ratio has attracted much attention for its advantages of fast response, high accuracy, and non-contact. Here, we report a series of novel GdAlGe2O7:Bi3+,Eu3+ phosphors with anti-thermal quenching properties for high sensitivity optical temperature measurement. By constructing the energy transfer between Bi3+ and Eu3+ ions, the GdAlGe2O7:Bi3+,Eu3+ exhibits a rare anti-thermal quenching performance upon 285 nm excitation due to the redshift of the charge transfer band. Therefore, we designed ratiometric optical thermometers with high sensitivity based on the intense thermal quenching behavior of the Bi3+ ions and the anti-thermal quenching property of the Eu3+ ions with a relative sensitivity of 1.06% K−1 at 483 K and an absolute sensitivity of up to 0.0447 K−1 at 573 K. Our results not only reveal the optical behaviors of the Bi3+ and Eu3+ ions in GdAlGe2O7:Bi3+,Eu3+, but also propose that the synthesized phosphors have significant potential applications in the field of optical temperature measurement.