On the correlation between mechanical and electrical properties of pure and Ag doped ZnO nanoparticles

We present here structural, mechanical, and electrical properties at different values of temperatures (30-150 °C) for Zn_1-xAg_xO nanoparticles (NPs) with x = 0.00, 0.02, and 0.04. All NPs samples show wurtzite structure, tensile stress, and brittle character. Ag doping resulted in a slight increase in crystallite size, along with reduction in dislocation density, micro-strain, specific surface area, porosity, particle size, and M-O spacing. The FTIR spectra exhibit various bands between 3450.69 and 411.3 cm^-1 for all samples, with most shifting to lower wavenumbers as x increases. With increasing Ag doping content up to 0.04, the Debye temperature, effective mass, elastic moduli, hardness, and wave velocities all gradually increased. The dielectric constant, dielectric loss, AC conductivity, and F-factor increase with increasing temperature (T) or doping content (x). In addition, the activation energy of the charge carriers, determined using the Arrhenius equation, decreased with increasing x or f, ranging from 0.187 to 0.68 eV across all samples. In general, no relaxation peaks are observed in the tan δ curves for x = 0.00 and x = 0.02 across the entire temperature range; however, for x = 0.04, clear relaxation peaks appear at 110 °C and 150 °C. The relaxation peaks are also evident in the electric modulus (M) and impedance (Z) curves for all samples, with their peak frequencies increasing with T or x. The frequency exponent (0.05 < s ≤ 0.55) indicates the conduction mechanism is the correlated barrier hopping. Meanwhile, the binding energy (0.163-0.345 eV) decreases as either T or x increases. The Cole-Cole plots reveal ideal semi-circular arcs corresponding to parallel RC representations for all samples. The impedance of grains, grain boundaries, and the series resistance (ranging from 2 × 10⁴ to 10⁸ Ω) decrease with increasing x or T, whereas the effective capacitance increases (0.005-38.73 µF). These findings establish a correlation between the mechanical and dielectric properties and highlight the promising potential of Ag-doped ZnO nanoparticles for further exploration in electronic and energy-related applications.