Optical and dielectric investigations on Ag: CdZnTe hybrid polyvinyl alcohol freestanding films

Abstract

Hybrid freestanding films of polyvinyl alcohol incorporated with silver and CdZnTe quantum dots were synthesized. The effect of varying silver concentration on optical and dielectric properties were studied. Structural and morphological analysis of hybrid films were done using X-ray diffraction and transmission electron microscopy. Optical parameters like absorption coefficient, extinction coefficient, refractive index, optical bandgap, urbach energy and optical conductivity were studied for the polymer nanocomposite for 0 to 0.3 wt percentage of silver content. With increasing silver content, a decrease in bandgap energy and an increase in urbach energy was observed. Dielectric constants, loss tangent and AC conductivity values of hybrid films were found to improve, with silver addition and highest values were obtained for 0.2 wt percentage. Complex impedance plots provided semicircles and Cole-Cole parameters were calculated. The nature of impedance plot revels single relaxation process and this was effectively modelled through an equivalent RC parallel circuit.