Studies on structural, photo and thermoluminescence properties of Sm³⁺ activated Ca₃MgSi₂O₈ phosphors for solid-state lighting

Abstract

The samarium activated orange–red-emitting calcium magnesium orthosilicates [Ca₃MgSi₂O₈:xSm³⁺ (CMSOSM)] phosphors with different concentration were synthesized by solid-state reaction method. The monoclinic crystal structure with P21/c space group was confirmed by the PXRD technique. Under the excitation at 405 nm, characteristics emission spectra of Sm³⁺ ions in orange–red region were recorded at 565 nm, 570 nm, 602 nm, and 648 nm due to the transition of ⁴G_5/2 → ⁶H_5/2, ⁶H_7/2, ⁶H_9/2 respectively. The critical doping concentration of Sm³⁺ ion was 2.0 mol% and the critical distance was determined as 32 Å. The energy transfer among Sm³⁺ ions in Ca₃MgSi₂O₈ (CMSO) phosphors was found to be a dipole–quadrupole interaction. Furthermore, it’s exciting to find that the red-emitting phosphors showed high thermal stability. Ca_2.98MgSi₂O₈:Sm_0.02 (CMSOSM2) exhibits a strong sharp peak at 104 °C was shoulder at 291 °C when heating rate (HTR) is constant 5 °Cs⁻¹. The shape of glow peak and intensity of isolated curve depend on dopant impurity rigorously, results in remarkable increasing in TL sensitivity. The photometric results indicate that the synthesized orange–red phosphor can be potentially applicable for solid-state lighting and display devices applications.