Eu3+-doped La2(MoO4)3 phosphor for achieving accurate temperature measurement and non-contact optical thermometers

In this study, La 2 (MoO 4 ) 3 doped with Eu 3+ was synthesized by the high-temperature solid-state method. The phase composition of the Eu 3+ -doped La 2 (MoO 4 ) 3 sample was confirmed by X-ray powder diffraction (XRD) analysis, and the microstructure was observed via the scanning electron microscopy (SEM). Under the excitation at 211 nm, the room temperature emission spectra of Eu 3+ in the samples with different doping levels were recorded. In addition, the prepared La 2 (MoO 4 ) 3 : x Eu 3+ ( x  = 0–0.25) phosphors were color tunable. A non-contact optical thermometer with high sensitivity and high-temperature resolution was fabricated based on the different thermal quenching behaviors of the Mo–O group and Eu 3+ center. The fluorescence intensity ratio (FIR), temperature resolution (ΔT), maximum absolute and relative sensor sensitivity (Sa and Sr) of La 2 (MoO 4 ) 3 :Eu 3+ were calculated according to different thermal quenching effects between room temperature (298K) and 573K of Eu 3+ and Mo–O group. These results show that La 2 (MoO 4 ) 3 :Eu 3+ has excellent sensitivity and temperature resolution, good reversibility and reliability, as Sa = 0.0525 K -1 , Sr = 0.3724. % K −1 , ΔT = 0.0806 K and the FIR error was only 0.62%. Therefore, the Eu 3+ -doped La 2 (MoO 4 ) 3 is a promising candidate material for high performance non-contact optical thermometers.