Synergic Effect of CdS Nano Additives and UV Exposure on Properties of PVA/CdS Nanocomposite

Abstract

PVA/CdS nanocomposites with varying amounts of CdS NPs in PVA were synthesized and subjected to UV irradiation. An absorption peak around 450 nm indicates the presence of CdS NPs in PVA. UV irradiation causes red shift in wavelength in absorption spectra, suggesting an increase in particle size after UV exposure. A decrease in transmittance of PVA after embedding NPs and further with UV exposure suggests that these can be used for UV-blocking devices. The band gap of PVA decreased with an increase in NPs and UV exposure time. An increase in the refractive index of PVA after embedding CdS NPs was observed, further increasing with increasing concentration of NPs and with increase of UV exposure. Structural induced changes in PVA after embedding NPs and with UV exposure were analyzed by Fourier transform infra-red spectroscopy. Field-emission scanning electron microscopy and energy-dispersive spectroscopy analysis confirmed the presence and distribution of NPs. Photoluminescence spectrum exhibits quantum confinement effect of CdS NPs embedded in polymer matrix. The thermal nature of nanocomposite films was investigated by DSC and TG. Dependence of electrical parameters on concentration of NPs and UV exposure time were studied and explained on the basis of formation charge-transfer complexes inside matrix.

Impacts of Low Energy Oxygen Irradiation on the Dielectric Properties of PVA/TiO2 Nanocomposite Films

“…illustrates the M' vs frequency for PVA/TiO 2 sheets at different fluences; 0.3 × 10 17 , 0.6 × 10 17 , and 0.9 × 10 17 ions cm −2 of oxygen beam. The M' value is almost 0 in the low frequency band, 24 as observed in the figure. At larger frequencies, there is an exponential relationship between M' and frequency.…”

Study of electrical and dielectric properties as an effect of nanoparticle concentration and UV irradiation of PVA-Ag nanocomposites

“…From figure 7 it is noticed that there is increase in s ac as the concentration of Ag in PVA increases and with time of UV exposure. This is due to changes in chemical composition of PVA chains because of generation of CTCs inside PVA and hence leading to increase in values of e″ [46]. In addition to this form figure 9 it is noticed that e″ reduces with increment in frequency.…”

PVA/CdS-Ag Nanocomposites: Effect of Composition and UV Radiation on Optical, Electrical and Structural Properties

“…) verses incident photon energy is plotted for prepared films and optical energy gap is estimated by extrapolating straight part on y-axis, and estimated values are tabulated in Table I. 23 Figure 4a illustrates that band gap of PVA has reduced in comparison when CdS-Ag nanostructures are incorporated in PVA matrix. Energy gap (E g ) value of virgin PVA film is 4.86 eV, which is observed to reduce as CdS-Ag nanostructures are incorporated in PVA.…”