Effect of LI Concentration on the Structural and Optical Properties of Co1-xLixCr2O4 Chromate Nanoparticles Prepared By Sol-Gel Method

CoCr2O4 and doped lithium Co1-xLixCr2O4 chromate powder and nanoparticles were prepared by modified by sol-gel method. The morphological and structural properties of nano chromates were investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy and Photoluminescence (PL). Nanoparticles of doped lithium were synthesized by adding appropriate amount of cobalt nitrate, chromium nitrate, lithium nitrate and 1,2 Ethanediol as a complexing agent. The sample were heated at 105 ˚C for ten hours in oven to obtain dry gel. Calcination temperature for these samples was 700˚C for 3 hours in a furnace. The particle size of parent compound ranges from 4.4 nm to 11 nm, determined by SEM. The tendency of particles to form the aggregates with the increased annealing temperature was observed. The SEM and optical characterization of this compound has shown the sol gel derived material may be successfully used as an effective doped lithium cobalt ceramic pigment with controlled variation in structural and optical properties. SEM images showed that spherical like doped particle have diameter 33nm. From PL spectra Nano structure shows band gap 2.5ev and when we doped Lithium in it band gap decreases and become 1.19ev, which is associated to band gap transition.