Fluorescent Temperature Characteristics of CaMoO4:5%Tb3+ Based on Variable Temperature Excitations

This study focuses on the fluorescent thermometric properties of CaMoO4:5%Tb3+ under different temperature excitations. At the detection wavelength of 544 nm, with the temperature varying from 293 K to 563 K, there is a broadband absorption peak in the range of 250 nm to 350 nm. The results indicate that this phenomenon is caused by the superposition of the 4f-5d transition of Tb3+ and the O2--Mo6+ charge transfer. It is considered that as the temperature rises, the luminescent intensity of the material shows an obvious continuous decreasing trend, which reflects a significant luminescent thermal quenching trend; thus, this quenching belongs to the “strong coupling” type. Based on the excitation spectrum results, two excitation wavelengths, 312 nm and 338 nm, were specifically selected to excite the samples, which correspond to the top of the charge transfer band, the redshift intersection of the charge transfer band, and the edge of the charge transfer band at 293 K, respectively.