LAUSR

To explore new upconversion materials for optical temperature sensing, a series of Tm3+-Yb3+ codoped Y4.67Si3O13 (YSO) phosphors was prepared by solid-state reaction. The phase composition was examined by XRD patterns, revealing that the samples are single-phase. Upon 980 nm excitation, four main emission peaks of Tm3+ were observed from the near-ultraviolet to the near-infrared region. The pump-dependence measurement indicates that the blue and near-infrared emissions of Tm3+ are three- and two-photon processes, respectively. By studying the temperature-dependence of the typical YSO:0.5%Tm3+,10%Yb3+ sample, it has been found that the fluorescence intensity ratios (FIRs) of both the 695/789 and 466/484 nm emissions increase with increasing temperature due to the thermally-coupled levels. The repeatability of measurement was examined by relative standard deviation and cycle test. The relative and absolute sensitivities of YSO:0.5%Tm3+,10%Yb3+ were evaluated.