Novel-approach for fabrication of CdS thin films for photoelectrochemical solar cell application

Abstract

In present report, we have successfully synthesized nanocrystalline nanosheet-like CdS thin films on ultrasonically cleaned bare and FTO-coated glass substrates by using self-organized arrested precipitation technique. The effect of annealing on opto-structural, morphological and electrical properties were studied by using UV–Vis–NIR spectroscopy, X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) equipped with energy dispersive spectroscopy (EDS) analyzer, X-ray photoelectron spectroscopy (XPS), electrical conductivity and thermoelectric power measurement. The UV–Vis–NIR studies revealed that band gap energy is varied from 2.23–2.05 and 2.00 eV with increase in deposition time and post annealing temperature (373 K), respectively. Also, optical absorption data indicates transition mechanism type is direct and allowed. The XRD study revealed that films are nanocrystalline in nature and pure cubic crystal structure with crystallite size ranging from 61 to 86 nm. FESEM micrographs confirm material is well adherent, pin-hole free over entire substrate surface. XPS shows presence of Cd2+ and S2− ions and EDS confirms Stoichiometric film formation. Finally as deposited and annealed (372 K for 1 h) thin films were tested for their photoelectrochemical properties. PEC results revealed that the annealed CdS thin film shows 0.846 mA cm−2 short current density (J sc ) with 0.10 % highest conversion efficiency (η).