Photoluminescence Characteristics Of ZnMgO Nanoparticles For Tunable visible Light And White Light Devices

Series of six Zn(100−x)-MgxO (for x = 0.0, 0.4, 0.8, 1.2, 1.6, and 2.0; in mol%) nanoparticles were prepared by chemical co-precipitation. The morphology of the nanoparticles was determined by SEM with EDAX studies. The typical particle size (D) was identified as 46–58 nm. The photoluminescence spectrum (excited at 350 nm) of pure ZnO nanoparticles showed five distinct emission bands in violet, violet-blue, blue, green, and yellow-orange regions. When MgO added to ZnO gradually, a clear blueshift was observed in the emission bands of shorter wavelength (violet, violet-blue, and blue) region with gradual decrease in their intensities; whereas, redshift was observed in the emission bands of longer wavelength (green and yellow-orange) region with gradual increase in their intensities. The emission band intensity ratio (I_SL = I_shorter/I_longer) was determined. This ratio, I_SL has indicated the existence of more number of oxygen defects (O_i and V_O) than zinc defects (Zn_i and V_Zn) at high MgO content in the ZnMgO nanoparticles. The CIE diagram revealed that the coordinates (x, y) of the ZnMgO nanoparticles are nearly close to those of ideal white light emitters (x≈0.33, y≈0.33). Thus, the ZnMgO nanoparticles may find the potential applications as optical materials.