Copper and nickel co-doping effects on the structural, optical and electrical properties of tungsten trioxide nanoparticles prepared by co-precipitation technique

Abstract

The pristine WO3 (tungsten trioxide) and Cu/Ni Co-doped WO3 nanoparticles were synthesized by the co-precipitation synthesis methods with fixed wt.% of nickel, i.e., 5 wt.%, and different wt.% of copper, i.e., 2, 3, 5 wt.%. The structural, optical and electrical properties, as well as the surface morphology were investigated thoroughly by various characterization techniques. All the doped/co-doped and un-doped samples had an orthorhombic structure, according to the XRD measurements. The XRD results further confirmed that the average crystalline size ranged from 46 to 25 nm after the dopant concentration was introduced. Reflectance spectroscopy was used to investigate the optical properties of the prepared nanomaterials and revealed that the optical band gap varied from 2.80 to 2.63 eV with dopant concentrations. The room temperature photoluminescence study showed that the emission peaks were observed in the visible region with slight peak shift towards short wavelength with dopant concentrations. The FTIR studies described the different mode of band related to a functional groups present in the materials and the stretching mode of O-W-W observed from 550 to 1050 cm-1. The I-V studies confirmed that the prepared samples had a good ohmic contact behavior and the resistivity decreased from 6.3 × 10-3ω.cm to 0.63 × 10-3 ω.cm with doping concentrations.