Investigation of energy band gap in polymer/ZnO nanocomposites

Polymers/ZnO nanocomposites have been receiving great interest due to their wide range of applications in optical devices. So, there is an essential need to enhance their optical properties. In this work, nanocomposites of four types of polymer and ZnO nanoparticles have been prepared as flexiable foil by using the casting method. Poly (methyl methacrylate) (PMMA), poly (vinylidene fluoride) (PVDF), polyvinyl alcohol (PVA), and polystyrene (PS) are used as polymer matrix while different concentrations of ZnO nanoparticles are used as filler. The analysis of energy dispersive X-ray (EDX) is satisfied of the high purity of as-prepared samples. UV-visible transmittance spectra have shown low transmittance in UV region which is inversely proportional with the concentration of ZnO nanoparticles. Linear absorption coefficient (alpha) has shown the presence of absorption edges. The energy gap is calculated, it is noticed that the optical band gap of all nanocomposites are red shifted. The values of the energy gap for all samples decreased with the increase of the weight percentage of ZnO nanoparticles in nanocomposites. However, the decrement in nanocomposites samples is different.