Enhancement of dual-mode emission and temperature sensing performance in Y2Zr2O7: Er3+ nano phosphor by incorporation of lithium ions

The present work has been planned with the primary objective to study the effect of Li+ doping on photoluminescence (PL) emission intensity and temperature sensing performance of Y2Zr2O7(YZO): Er3+ phosphors. The hydrothermal method was employed to synthesize the YZO: 4Er(3+), xLi+ (x = 0, 3, 5, 10 mol%) phosphors. The formation of the phase and the crystallinity of the prepared samples were examined from the XRD results. The cell parameters were estimated from Rietveld refinement. The surface morphology and elemental analysis were studied using the FESEM and EDX techniques. UV-Vis-NIR diffuse reflectance spectroscopy was utilized to find the optical band gap of the prepared samples. The Li+ doped sample exhibits better optical absorption than the sample without Li+ ions. The FTIR spectroscopy confirms the presence of the desired functional groups within the samples. XPS measurements were performed to find the bonding state of the compositions. Photoluminescence down-conversion and up-conversion measurements were carried out under 378 nm and 976 nm excitation, respectively. The optical thermometry of the prepared phosphors was investigated within the temperature range 303K-630K. The reported phosphor shows a significant amount of intensity enhancement after Li+ doping in both the down conversion and up conversion processes. In general, the charge compensation effect is used to explain this type of result. As the phosphor is already charge balanced, the phenomenon mentioned above cannot be considered. We have explained the various contributing factors responsible for the changes in intensity and correlated them with the different experimental results collected by characterizing the prepared samples. Overall, the obtained results suggest that the reported phosphor may act as multifunctional material.