Growth and characterization of nanostructured CdS/Polyaniline/CuInSe2 thin films for solar cell applications

Abstract In the present paper, we report about synthesis of nanostructured organic–inorganic heterojunction of CdS/Polyaniline/CuInSe 2 thin films by cost effective chemical route at room temperature, for solar cell application. As such obtained thin films are characterized for structural, compositional, morphological, optical and electrical properties by X-ray diffraction (XRD) pattern, energy dispersive X-ray (EDAX) analysis, scanning electron microscopy (SEM), optical absorbance spectra and I–V response respectively. The XRD reveals the polycrystalline nature of the thin films having tetragonal crystal structure and a crystallite size of 19 nm. The presence of observed and expected elements in the EDAX spectra confirms the elemental compositions in CdS/Polyaniline/CuInSe 2 thin films. From SEM images it can be inferred that the surface morphology of the Polyaniline thin films exists like clothing fibers, while CdS/CuInSe 2 shows granular shape particles distributed over the substrate and the SEM of CdS/Polyaniline/CuInSe 2 represents mixing and attachment of circular particles to fiber like structure. The optical absorbance spectra have shown red shift in absorbance strength and energy band gap value of CdS/CuInSe 2 from ~ 1.36 eV to ~ 1.62 eV upon formation of CdS/Polyaniline/CuInSe 2 thin film. The I–V response of CdS/CuInSe 2 and CdS/Polyaniline/CuInSe 2 measured under dark and illumination to 100 mW/cm 2 light, exhibited the solar characteristics from these graphs and the conversion efficiency calculated is observed to be 0.26 and 0.55% for CdS/CuInSe 2 and CdS/Polyaniline/CuInSe 2 thin films respectively.