Synthesis and Characterization of Sm $^{3+}$ –Yb $^{3+}$ Codoped Y

The Y₂O₃ phosphors doped/codoped with Sm³⁺/Sm³⁺-Yb³⁺ ions at different concentrations have been prepared using combustion technique. The prepared phosphors are characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The average crystallite size of the phosphors calculated based on the XRD is observed to increase with annealing. The FTIR analysis suggested that the impurity is reduced on annealing the sample. NIR to visible frequency upconversion emission has been observed from synthesized phosphors upon a 980 nm diode laser excitation. The concentration dependence study shows a tuning in light color emitted from samples. The upconversion mechanism involved in the Sm³⁺/Sm³⁺-Yb³⁺ doped/codoped Y₂O₃ phosphors has been explained on the basis of excited state absorption (ESA) and energy transfer (ET) process.