UV radiation emitting Gd3+ activated Sr2SiO4 host system prepared by sol–gel procedure: structural, electron paramagnetic resonance, and luminescence studies

Abstract

Trivalent gadolinium (Gd3+) activated strontium silicate (Sr2SiO4:xGd3+; 0.01 ≤ x ≤ 0.11) systems have been synthesized via sol–gel technique. The structural, morphological, luminescent, and magnetic properties have been investigated using X-ray diffraction patterns, scanning electron microscopy (SEM), photoluminescence (PL), and electron paramagnetic resonance (EPR) technique, respectively. The synthesized strontium silicate samples exhibit a mixed phase of α′ and β-Sr2SiO4. The SEM images show irregular morphologies with a random distribution of particles. The PL spectra confirm the ultraviolet emission from the synthesized samples and the optimum concentration of Gd3+ ions is observed at 0.05 mol. With low dopant concentrations, Sr2SiO4:Gd3+ sample displays EPR lines, mainly in the low field region with effective g-values 5.8, 4.5, 3.1, and 2.7. As dopant concentration increases, a broad line appears with geff ~ 2.1 along with the low field lines. A relatively strong crystal field is experienced by Gd3+ ion due to distortions in the immediate environment of the ion, which lead to low field EPR lines. These studies allow the use of gadolinium-activated strontium silicate in phototherapy lamps.