Study of optical and dielectric properties of alkali metal cation (Li+, Na+, K+) codoped Eu3+ activated gadolinium aluminate nanoparticles

In the present work, solution combustion method is used to synthesize GdAlO3 nanophosphors, doped with Eu3+ (1 mol%) and Co-doped with alkali metals such as Li+, Na+, K+ (1 mol%) using ODH (oxalyldihydrazide) as fuel. The morphological details have been investigated using various analytical techniques. X-ray diffraction patterns reveal the formation of pure, orthorhombic structured nanoparticles in the Pbnm phase group having an average crystallite size of about 45-60 nm. The functional groups and chemical interactions were probed using the FTIR spectrum. The agglomerated spherical shaped nanoparticles were evidenced by SEM micrographs. The optical energy gap (E-g(opt)), Urbach energy (Delta E) and refractive index (n) were determined by UV spectroscopy from the direct allowed transitions. Due to the highly stable physical and chemical properties, rare earth doped nanocrystals have been widely employed miniaturized dielectric devices. The dielectric and electrical properties are measured in the frequency ranging from 10 Hz to 8 MHz at RT using an LCR meter. The synthesized nanoparticles have a high dielectric constant in the low-frequency region and at the higher frequency region, the low dielectric loss was observed. Thus, these nanomaterials find potential utility for high-frequency applications.