Photoluminescence characteristics of Sm3+ activated Y2SiO5 orange emitting phosphors

Abstract

The structural and photoluminescence characteristics of sol-gel-derived Y2SiO5 activated with triply ionized samarium ions were examined. Structural analysis was performed using XRD (X-ray diffraction) and FT-IR (Fourier Transform Infrared) spectral measurements. Lattice expansion was observed with an increased concentration of Sm3+ ions in the Y2SiO5 phosphor due to increased crystallite size. The observed spectra of diffuse reflectance and emission spectra of Y2SiO5 phosphors doped with Sm3+ ions were used for the analysis of optical and luminescence characteristics. J-O intensity parameters, Ω2 = 0.16 × 10−20 cm2, Ω4 = 0.16 × 10−20 cm2 and Ω6 = 0.16 × 10−20 cm2 were obtained for the Y2SiO5:0.03Sm3+ phosphor. Radiative transition probabilities (Arad), radiative lifetimes (τrad), and branching ratios (β) for a certain Sm3+ ion transition are presented. Photoluminescence spectra of Sm3+ activated Y2SiO5 phosphors show an orange emission under the n-UV excitation of phosphor. Dexter's theory on emission spectra supports the existence of dipole-dipole interactions between dopant ions. Furthermore, photometric and colorimetric studies were also accomplished to determine the emission behavior of the synthesized phosphors for their application in w-LEDs.