Improving the temperature-dependent sensitivity of Ca9Y(PO4)7:Ce3+,Mn2+ and g-C3N4 composite phosphors by mechanical mixing

Measurement of the optical temperature based on fluorescence intensity ratio (FIR) technology is a promising research direction owing to a rapid response performance that is undisturbed by external circumstances. The composite phosphors of Ca9Y(PO4)7:0.05Ce3+,0.05Mn2+ and g-C3N4 (CYPO:Ce3+,Mn2+/g-C3N4) with different proportions were prepared by mechanical mixing. Thermometric properties were explored for application in highly sensitive optical-temperature measurement. The properties of composite phosphors were analyzed by X-ray powder diffraction and fluorescence spectroscopy. Compared with pure CYPO:Ce3+,Mn2+, the composite phosphors of CYPO:Ce3+,Mn2+/g-C3N4 showed better temperature-dependent properties. The maximum absolute and relative sensitivities of the designed composite phosphors were 0.11 K−1 at 447 K and 1.673% K−1 at 547 K based on the FIR. This work provides a feasible idea for optical-temperature measurement by exploring the diverse photoluminescence behaviors of the CYPO:Ce3+,Mn2+ and g-C3N4 to realize versatile applications.