Preparation and characterization of CdS nano particles using chemical precipitation method for solar cell applications

Cadmium sulfide (CdS) nanoparticles were prepared using cadmium sulphate and sodium sulphide as precursor by chemical precipitation method. The synthesized CdS material was annealed at 300, 400 and 500 degrees C to study the effect of temperature on size and surface morphology. The prepared CdS was characterized using X-ray diffraction (XRD), Ulta-violet spectroscopy (UV-Vis), scanning electron microscopy (SEM) and photoluminescence (PL). The XRD pattern of CdS reveals the nano -sized hexagonal crystalline structure at 300 degrees C. The hexagonal structure of the CdS was converted into cubic CdO and monoclinic CdSO3 at 400 and 500 C by partial oxidation. The average crystallite size of the CdS, CdO and CdSO3 obtained at 300, 400 and 500 degrees C was 24, 26 and 31 nm, respectively. It shows the particle size of the materials was slightly increased at elevated temperature. The SEM analysis of CdS shows that the CdS particles are agglomerated particles at 300 degrees C. It also reveals that the morphology of CdO and CdSO3 at 400 and 500 degrees C is changed into cluster structure. The UV-Vis absorption spectroscopy reveals that the optical absorption increased from 425 to 490 nm from 300 to 500 degrees C. At the same time, the band gap energy of the CdS decreased from 2.91 to 2.53 eV. The average particle sizes of the different forms of CdS were 39, 47 and 49 nm at 300, 400 and 500 degrees C, respectively. The present study reveals that the synthesized CdS could be used as a material for solar cell applications.