Comprehensive study of optical, photocatalytic and dielectric properties of CdMnZnO annealed nanocomposites.

The structural, optical, photocatalytic and dielectric properties of CdMnZnO annealed nanocomposites prepared by Hydrothermal and subsequently annealed at temperatures between 200 °C and 600 °C. The particle size, crystallite size, and inter-plane separation were all enlarged with increased T at 600 °C and electrical dielectric loss increased. The specific surface area and photocatalytic activity were maximized, obtaining in this case a rate of degradation of 2 × 10s at 400 °C. The lowest band gap = 1.55 eV was observed at 400 °C signifying enhanced optical absorption. The optical and dielectric properties exhibited a non-monotonic behavior: absorbance, optical dielectric loss, carrier density, dielectric constant, ac conductivity and Fill-factor, increased to the maximum values at 300 °C followed by a decrease. The dielectric constant (3.22), single and dispersion energies (10.58 eV and 23.33 eV), impedance (3.25-10.70 MΩ) and series resistance (14.3 MΩ) were maximum at 500 °C. From loss, modulus, and impedance curves, relaxation times were calculated by being 82.71 µs, 0.69-10.62 µs, and 15.92-40.94 µs. Two successive semicircles were identified in Cole-Cole plots for the composites after annealing in the range 200-500 °C. Results show composites annealed at 200-400 °C can be utilized for solar cell, supercapacitor, telecommunications, and water purification applications while those annealed at 500-600 °C are more suitable for a high frequency, nonlinear optical, and high-power antenna applications.