Sm3+ Doped Lithium Strontium Borate Glasses for Solid State Lighting Applications

Abstract

The glasses of samarium (0.1, 0.2, 0.5, 1.0, 1.5 and 2.0 mol %) doped lithium strontium borate samples were synthesized. The physical and optical properties are studied at ambient conditions and discussed in this study. XRD spectra reveals the no atomic order in structure (amorphous) present in these glasses. Infrared spectroscopic study reveals the structural units of borate viz., BO₃ and BO₄ group present in the matrix. Interestingly, it is found that as the rare earth concentration increases and beyond 1.5 mol % the luminescence intensity decreases due to non-bridging Sm³⁺ ions in the glass network. The peaks in absorption spectra are due to dipole transition from ⁶H_5/2 to levels corresponds to ^{(2S + 1)}L_J excited states under the excitation wavelength of 402 nm. Judd–Ofelt theory applied to estimate dipole strength in terms of J–O parameters (Ω₂, Ω₄ and Ω₆), oscillator strength (f_exp and f_cal), radiative transition possibility (A_R), branching ratio (β_R) and stimulated emission cross section (σ) of the glass samples. From Judd–Ofelt analysis the parameters obtained are shown for 1.50 mol % of Sm³⁺ doped lithium strontium borate (LSB) glasses studied, which were compared with other glasses. The obtained results suggest their potential candidature for using as solid state material lighting applications due their efficient orange emissions.