Optical and electrochemical properties of pure and Ti-doped CdO nanoparticles for device applications

•The structural, optical, and electrochemical properties of pure CdO and Ti doped CdO nanoparticles were investigated.•Structural analysis was done using XRD and the average crystallite sizes were calculated.•Band gap, Urbach energy, optical conductivity, real and imaginary part of dielectric constant, dielectric loss tangent were calculated.•Optical band gap of CdO nanoparticles was tunned from 2.14 eV to 2.99 eV by Ti doping.•The maximum specific capacitance of 390 F/g and 219 F/g was observed for pure and Ti-doped CdO nanoparticles. Cadmium oxide (CdO) is one among the transparent conducting oxides which is famous for its various applications in optoelectronics, gas sensors, and electrochemical sensors, etc. The present work therefore reports the synthesis and structural, optical, and electrochemical properties of pure CdO and Ti doped CdO nanoparticles which were synthesized using simple sol–gel method. The structural analysis of the prepared samples was done by using x-ray diffraction (XRD) technique. The XRD peaks revealed the existence of crystalline structure of the samples. The average crystallite sizes of the samples were calculated by considering the intense peaks observed in the XRD spectrum and they were found to be 59.45 nm and 55.25 nm for pure CdO and Ti doped CdO nanoparticles respectively. The absorption and transmission spectra of synthesized nanoparticles were recorded in the UV–VIS-NIR region. Using the absorption and transmission spectra, the optical band gap of pure CdO and Ti doped CdO were estimated as 2.14 eV and 2.99 eV respectively, using Tauc plot method. The Urbach energies were calculated, and they were found to be 1059 meV and 679 meV for the pure and Ti doped CdO nanoparticles. The optical conductivity, real and imaginary part of dielectric constant, dielectric loss tangent were also investigated using UV–VIS-NIR spectral data for the possible application in opto-electronic devices. The electrochemical performance of the samples was investigated using cyclic voltammetry (CV) technique. The specific capacitance and diffusion coefficients were calculated using the recorded cyclic voltammogram. The results of CV data showed that the maximum specific capacitance was occurred to be 390F/g at the rate 25 mV/s and 219F/g at the rate 50 mV/s for the pure and Ti-doped CdO nanomaterials respectively. The outcome of the present study provided an useful information for the possibilities of these materials in the device applications.