Nanoparticles of Sr0.995Gd0.005ZrO3-gel-combustion synthesis, characterization, fluorescence and EPR spectroscopy

• Undoped and SrZrO3:Gd3+ were prepared by gel-combustion route.
• Synthesis temperature is brought down to as low as 600 °C.
• Evidence for the presence of two rare earth ion sites in the matrix.
• EPR spectrum exhibits typical U-shape.
• Most of the Gd3+ occupies Sr2+ site.

Undoped and Sr0.995Gd0.005ZrO3 were prepared by “the gel-combustion route” using citric acid as fuel. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), dynamic light scattering (DLS), photoluminescence (PL) and electron paramagnetic resonance (EPR) spectroscopy. Upon UV light excitation (274 nm), the phosphor exhibits a strong and sharp UV emission at 313 nm, which is ascribed to 6P7/2 → 8S7/2 transition of Gd3+ ions. Life time spectroscopy showed the presence of two types of Gd3+ ions. The EPR spectrum of Gd3+ doped SrZrO3 exhibits typical U-shape with resonance signals having effective g values at g = 2.0, 2.8, 4.8 and 6.0. The g values at 2.8, 4.8 and 6.0 are due to presence of Gd3+ ion at Sr2+ site having high coordination number (C.N = 8) whereas relatively sharp signal at g = 2.0 is attributed to isolated Gd3+ ion in polycrystalline region.