Structural, electronic and optical characteristics of TiO2 and Cu-TiO2 thin films produced by sol-gel spin coating

Abstract

Sol-gel spin coating was employed to deposit titanium dioxide (TiO2) and Cu-TiO2 composites on glass substrates. Cu was utilized as a dopant in varying amounts. The structural, morphological, optical, and dielectric characteristics of the produced samples were evaluated using a variety of techniques. XRD analysis was used to confirm the anatase (TiO2) phase's existence. After adding Cu(NO3)2.3(H2O) to TiO2, it was observed that Cu atoms were mostly distributed on the TiO surface, resulting in a decrease in the particle size, as revealed by the TEM images. Raman Spectroscopy and FTIR analysis indicates the expansion of the lattice TiO2 with Cu amount and the formation of vibrating Ti-O-Ti bonds respectively. With increasing dopants, spherical nanoparticles begin to form and orient themselves to aggregate, as shown in the AFM's noticeable shift in roughness. The UV–vis spectroscopy revealed a shift of the absorption peak toward visible range that signified an increase in the bandgap after doping. The theoretical study using quantum espresso ab initio simulation and DFT + U correction were used to derive the electronic band gap energy values which are consistent with our experimental results.