Effect of annealing temperature on the spectroscopic and photoluminescence properties of CdO-ZnO nanocomposites.

The annealing temperature of CdO-ZnO (3:1) particles that were derived by using a sol–gel precipitation method has been optimized in order to improve the photoluminescence (PL) efficiency. The CdO-ZnO particles have been characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), impedance spectroscopy and UV–VIS spectroscopy. The transition point was found near 32°C with DSC for the highest annealing temperature (600°C). The impedance (Z) and phase angle (θ) as functions of frequency were recorded and the CdO:ZnO particles annealed at 450°C has the lowest 8.2–6.8 kΩ impedance. The reflectance spectra in the range of 300–800 nm were recorded and the optical bandgap was found varied from 2.76 to 2.99 eV. The excitation and emission PL spectra were obtained and the sample annealed at 600°C showed an intense blue emission with respect to the other samples. [ABSTRACT FROM AUTHOR]