NIR Light-triggered Green Emitting Perovskite-based Phosphor for Optical Thermometry and Future Molecular Logic Gate Applications

Er³⁺ and Yb³⁺ doped CaTiO₃ phosphors were synthesized via the solution combustion method and analyzed for structural, morphological, and optical properties using X-ray powder diffraction, field emission scanning electron microscopy, and photoluminescence spectroscopy. The Er³⁺ ions showed green and red emissions when excited by a 980 nm infrared source. Power-dependent emission spectra were used to study the up-conversion process, and a rate equation model was proposed for clarity. For temperature sensing, the phosphor’s temperature-dependent emission lines were examined between 303 and 583 K. This analysis was conducted using the fluorescence intensity ratio method. Relative sensitivities of 1.14%, 1.66%, 0.15%, and 0.33% K^-1 were observed for various thermally and non-thermally linked transitions. The phosphor also demonstrated potential for molecular logic gate applications, achieving switching ratios of ~ 170.86% for the AND gate and ~ 72.28% for the INHIBIT gate when heat and IR excitation were used as inputs. This material shows promise for both optical thermometry and future molecular logic devices.