The Upconversion Luminescence of Ca(3)Sc(2)Si(3)O(12):Yb(3+),Er(3+) and Its Application in Thermometry

To develop novel luminescent materials for optical temperature measurement, a series of Yb(3+)- and Er(3+)-doped Ca(3)Sc(2)Si(3)O(12) (CSS) upconversion (UC) phosphors were synthesized by the sol–gel combustion method. The crystal structure, phase purity, and element distribution of the samples were characterized by powder X-ray diffraction and a transmission electron microscope (TEM). The detailed study of the photoluminescence emission spectra of the samples shows that the addition of Yb(3+) can greatly enhance the emission of Er(3+) by effective energy transfer. The prepared Yb(3+) and Er(3+) co-doped CSS phosphors exhibit green emission bands near 522 and 555 nm and red emission bands near 658 nm, which correspond to the (2)H(11/2)→(4)I(15/2), (4)S(3/2)→(4)I(15/2), and (4)F(9/2)→(4)I(15/2) transitions of Er(3+), respectively. The temperature-dependent behavior of the CSS:0.2Yb(3+),0.02Er(3+) sample was carefully studied by the fluorescence intensity ratio (FIR) technique. The results indicate the excellent sensitivity of the sample, with a maximum absolute sensitivity of 0.67% K(−1) at 500 K and a relative sensitivity of 1.34% K(−1) at 300 K. We demonstrate here that the temperature measurement performance of FIR technology using the CSS:Yb(3+),Er(3+) phosphor is not inferior to that of infrared thermal imaging thermometers. Therefore, CSS:Yb(3+),Er(3+) phosphors have great potential applications in the field of optical thermometry.