Influence of polyaniline doping concentration in (Bi0.5Sb0.5)2S3 thin polycrystalline films on structural, electrical and optical properties

The electrodeposition of as-deposited polycrystalline (Bi0.5Sb0.5)2S3 thin film and polyaniline doped thin films for three different concentrations from aqueous acidic bath onto stainless steel substrate and ITO coated conducting glass substrate is described. The influence of PAni on the film formation and deposition mechanism is discussed using I–V studies. X-ray diffraction studies show polycrystalline nature of the thin films with orthorhombic structure for all the films deposited at room temperature. The crystallite size is found to increase with increase in PAni concentration. The surface morphology of the doped films changes due to the addition of PAni. The optical studies reveal that the band gap values decrease from 2.06 eV to 1.68 eV as the PAni concentration increases. PAni doped films show shifts in the FTIR peaks at 1024 cm− 1 and 1373 cm− 1. Electrical conductivity measurements carried out at different temperatures indicate that all the films follow Arrhenius behavior and that the activation energy decreases with increase in PAni concentration.