Pump power-responsive optical thermometry of titanate phosphors via TCLs and NTCLs based LIR techniques

Abstract

A new strategy for modulating the optical thermometric performance of the Er3+-Yb3+-Mo6+ doped/co-doped CaBi4Ti4O15 phosphors with laser excitation power has been demonstrated in this paper. The structural, functional, optical and thermometric properties of the phosphors prepared at 1100 ºC using the solid-state reaction method have been studied thoroughly. The influence of Yb3+-MoO42- complex on the upconversion emission intensity of the Mo6+ ion co-doped phosphors have been explained with a suitable energy level diagram. Despite having the massive reputation of the luminescence intensity ratio (LIR) technique in estimating the temperature sensitivity, the limitations and further improvement using non-thermally coupled levels (NTCLs) have been discussed. The dependence of maximum sensitivities and thermal quenching ratios on the laser excitation power has been noticed. The maximum relative sensitivities of ∼0.0120 K−1 at 303 K and 0.0104 K−1 at 498 K corresponds to the TCLs and NTCL based LIR technique, respectively at 1.56 W/cm2 confirms the optical temperature measurement in a wide temperature range.