Study of the doping effect of CoCl2 on the structural, optical and electrical properties of polyvinyl alcohol (PVA)

Abstract

Cobalt chloride (CoCl2) doped with polyvinyl alcohol (CH2CHOH) n films, were synthesized by solution casting method. The pure PVA and doped [PVA: CoCl2] films were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, dc electrical conductivity and UV–VIS spectroscopy. The SEM analysis confirmed the presence of uniformly distributed Co2+ ions in the polymer matrix. FT-IR spectra provide information on the structure of the doped PVA and signify the intermolecular hydrogen bonding between Co2+ ions with the OH group of PVA. From the optical studies, it is found that the optical band gap (Eg) decreases with an increase in the dopant concentration. The dc electrical studies revealed that the conductivity of the doped PVA is significantly higher than that of pristine PVA and conductivity is found to increase with the temperature. The activation energy decreases at the lower concentrations of cobalt chloride, whereas it becomes constant at higher concentrations

Keywords

• Polyvinyl alcohol
• Cobalt chloride
• Doped films
• Dc conductivity
• Optical study