Optical thermometry using up and down conversion photoluminescence mechanism in Y2Zr2O7: Er3+ phosphors with excellent sensing sensitivity

In this article, photoluminescence up and down conversion properties of Er3+ activated Y2Zr2O7 (YZO) phosphors have been investigated. All the compositions have been synthesized via hydrothermal method. Various characterization techniques have been used to characterize the samples. Powder X-ray diffraction reveals the crystallization of the fluorite phase of all samples. FESEM technique and EDX spectroscopy were performed for surface morphology and elemental analysis of the samples. The optical band gap is appeared to increase after doping. Photoluminescence down conversion (DC) excitation (PLE) spectra exhibit a strong near UV absorption at 378 nm. All the doped samples under 378 nm excitation display the featured emission of Er3+ ions. The variation of DC PL intensity and the lifetimes with temperature were also investigated within the temperature range 77K-475K. Excitation power dependent up conversion (UC) emission and temperature dependent UC emission spectra within 303K-483K of the optimized sample were examined with 980 nm laser excitation. The fluorescence intensity ratio (FIR) technique and the variation of the average lifetime with temperature have been used to study the temperature sensing behaviour of the reported phosphors. Comparatively high sensitivities suggest the reported phosphors could have potential applications in temperature sensing and also could be a UV and NIR to green converter phosphors material. (C) 2020 Elsevier B.V. All rights reserved.