Thermal, structural and optical investigation of Cu-doped ZnO nanoparticles

Well-dispersed undoped and copper-doped zinc oxide nanoparticles (Zn1-xCuxO, x - 0, 1, 5 and 10 wt.%) have been synthesized by precipitation method at room temperature. X-ray diffraction data revealed that the undoped and copper-doped zinc oxide nanoparticles are in phase pure wurtzite structure and the crystallite size increases from 24 nm to 36 nm with increase in dopant concentration. The optical band gap was found to decrease with increasing dopant concentration, which clearly indicates the blue shift. High-resolution scanning electron microscope image shows that the synthesized samples consist of an assembly of nanopetals. Transmission electron microscope image also confirmed the average particle size of 2050 nm. Energy-dispersive X-ray spectrum shows that the prepared samples are free from impurities. Photoluminescence spectra exposed that copper ions are doped into the lattice positions of ZnO. A simultaneous differential scanning calorimeter/thermogravimetric analysis combination was used to study the phase variations.