MICROWAVE-ASSISTED SYNTHESIS OF Cr-DOPED Gd2O3 NANOSTRUCTURES AND INVESTIGATION ON MORPHOLOGY, OPTICAL, AND PHOTOLUMINESCENCE PROPERTIES
Vinayak Adimule, Basappa C. Yallur, Sheetal Batakurki, Adarsha Haramballi Jagadeesha Gowda
Abstract
In the present study, pure and chromium (Cr)-doped gadolinium oxide (Gd2O3) nanostructures (NSs) (2%, 5%, and 8%) were successfully synthesized by a microwave-assisted solution process technique. The X-ray diffraction and scanning electron microscopy results revealed that single-phase crystals appeared in up to 8% of the Cr-doped NSs and a secondary phase of GdCr2O4 formed beyond an 8% increase in Cr concentration. The spherical-shaped morphology observed for Cr:Gd2O3 NSs had average particle sizes varying between 80 and 150 nm. The ultraviolet-visible spectroscopic results exhibited absorption maxima between 345.1 and 411. 1 nm and the Eg value decreased from 3.46 to 2.85 eV as the Cr concentration increased. The X-ray photoelectron spectroscopy results suggested that the Cr+3 ions were well incorporated into the Gd2O3 NSs, with a high-energy Gd 3d3/2 peak appearing at 1222 eV. The room temperature photoluminescence spectra exhibited a blue emission peak, which was found to increase with an increase in the Cr content. In addition, a broad emission peak appeared at 463.4-495.5 nm, which is characteristic for Cr insertion in Gd2O3 NSs; an increase in Cr+3 ions beyond 8% supressed the blue emission peak. The results strongly suggest that the Cr:Gd2O3 NSs form a new class of luminescent materials.