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.

Gd2O3:Er3+@Gd2O3:Yb3+ core-shell nanofibers with cubic phase were successfully fabricated by electrospinning method. The structural, morphological properties were investigated by X-Ray diffraction, scanning electron microscopy. Under 980 nm excitation, the upconversion photoluminescence in visible light exhibits strong red emitting band with obvious splitting peaks resulted from stark splitting of energy level. The visible emissions are sensitive to temperature in the range of 303-543 K. The red emission displays quenching with elevation of temperature. The activation energy for thermal quenching is equal to 0.1408 eV. The temperature dependent multi-peaks of red emission were systematically investigated. Based on valley and peak ratio of I680.31nm/ I683.03nm in upconversion emission spectra, temperature sensing with constant absolute sensitivity was achieved. These results suggest Gd2O3:Er3+@Gd2O3:Yb3+ nanofibers are promising candidates for luminescence thermometry, which may provide their application values in both scientific research and industry.