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.