Electrical and thermal characterizations of synthesized composite films based on polyethylene oxide (PEO) doped by aluminium chloride (AlCl3)

Polymer electrolytes based on poly(ethylene oxide)-aluminium chloride (PEO-AlCl3) are synthesized by the casting method. The crystal structure, chemical bonding, thermal, and electrical properties are investigated and correlated. Particularly, the interplay between the electrical conductivity, crystallinity, and thermal properties of the nanocomposite thin films is tested. Incorporating of suitable amounts of AlCl3 into PEO thin films reduces the crystallinity degree and the crystallite size of the resulting nanocomposite thin films. The measured FTIR profiles confirm the complexation between Al-3 ions and the ether oxygen of the PEO host polymer. Furthermore, the melting temperature and melting enthalpy are significantly reduced by adding the ionic salt into the PEO thin films. Electrical characterization of the PEO-AlCl3 thin films is performed using the four-point probe. The electrical conductivity, the conductivity maps, and activation energy of PEO-AlCl3 nanocomposite films are investigated to elucidate the effect of the complexation between Al-3 ions and the ether oxygen of the host polymer. The room temperature conductivity of the pure PEO thin films is measured to be 1.67 x 10(-4) S/cm. The highest value of the conductivity is attained for PEO doped by 5 wt% of AlCl3. Moreover, electrical conductivity of all PEO-AlCl3 nanocomposite thin films is found to enhance with increasing temperature. The optimized conductivity of PEO nanocomposite films doped by 20 wt% AlCl3 at 328 K is attained. The enhancement of physical and chemical properties of PEO-AlCl3 may pave the way to manufacture polymer nanocomposite films that could be potential candidates to fabricate high-efficiency photovoltaic devices.