Facile synthesis of Cu/N co-doped TiO2 nanoparticles and their optical and electrical properties

In the present work, pure and copper/nitrogen (Cu/N) co-doped TiO2 nanoparticles (NPs) with various Cu concentrations have been synthesized via sol–gel route. The optical and electrical properties of the prepared pure and Cu/N-doped TiO2 NPs have been assessed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscope, Brunauer, Emmett and Teller method and UV–Vis spectroscopy. The results show that the addition of suitable amounts of Cu and N content in TiO2 can alter its optical and electrical properties by extending absorption in the visible region and band gap reduction. XPS and XRD measurements suggest that some of the Ti sites are replaced by Cu atoms, while O sites are occupied by N atoms. An adequate addition of Cu/N in TiO2 could lead to smaller particle size, higher specific surface area, increased dye adsorption and retarded charge carrier recombination. An optimized 0.3 mol% Cu/N-doped sample shows a significant change in band gap value of TiO2 from 3.2 to 2.78 eV, enabling it to respond in the visible region. Hence, it can be used as a suitable alternative nanomaterial for dye-sensitized solar cell photoanode application and for photocatalysis operation as well.