Luminescence thermometry based on downshifting and upconversion photoluminescence of Bi4Ti3O12:Yb3+/Pr3+ ceramic

Yb3+/Pr3+ codoped Bi4Ti3O12 (abbreviated as Bi4Ti3O12:Yb3+/Pr3+) ceramic was successfully fabricated by solid state sintering method. The structural, morphological and luminescence properties were investigated by X-Ray diffraction, scanning electron microscopy, steady-state downshifting and upconversion photoluminescence spectra. Green and red downshifting emissions can be effectively excited by 450 nm blue light irradiation. The intensity ratios of downshifting green and red emissions are sensitive to temperature. The spectral positions of downshifting green and red emissions show blue-shift with elevation of temperature. Under 980 nm excitation, the tempreature dependent upconversion photoluminescence were recorded. Based on fluorescence intensity ratio of 545 nm and 623 nm in upconversion emission spectra, temperature sensing was achieved with maximum absolute sensitivity value of 0.0068 K-1 at 443 K. These results show Bi4Ti3O12:Yb3+/Pr3+ ceramic is a promising candidate for luminescence thermometry, which may find its applications in the scientific research and industry.