Poly (3,4-ethylenedioxythiophene):Polystyrene sulfonate (PEDOT:PSS) is a dispersion used as a buffer layer on the ITO electrode in the organic solar cells. Silver nanoparticles (Ag NPs) are incorporated to the dispersion using two different strategies. The first is by reduction of silver ions in the PEDOT:PSS dispersion. Chemical reduction of silver ions using sodium borohydried is compared with reduction using gamma radiation. The TEM and UV-visible spectra indicates that smaller Ag NPs are obtained for the chemical reduction method than those obtained from the radiochemical. The second strategy, is by preparing Ag NPs in polyvinyl pyrolidone (PVP) solution using gamma irradiation then adding them to the PEDOT:PSS dispersion. Layers of the PEDOT:PSS incorporated different concentrations of Ag NPs (1, 2, 4, 6, 8, 10%) are formed. The SEM and AFM studies of the layers morphology reveal that smooth morphology on the obtained for layers containing Ag NPs up to concentrations of 4%.

The objective of this research was to investigate the miscibility behavior of urea-formaldehyde (UF) resin and vinyl acetate versatic ester copolymer latex (VAcVe) blends. Blend of various compositions of UF resin as thermoset polymer and VAcVe as thermoplastic polymer were prepared. This study shows how the addition of VAcVe latex can alter the behavior of UF resin toward hardness, press-ability, and inhibition of cracks occurred in the UF resin films and moulds. After that, these blends (UF/VAcVe) were irradiated with gamma rays in different doses. Physical properties such as solubility percent, water absorption behavior in water, and effect of dilute acid and dilute alkali were studied. Thermogravimetric analysis shows that VAcVe is more stable against thermal decomposition than UF resin over the entire temperature range studied. Also, the thermal stability of polymer blends (UF/VAcVe) increases with increasing the ratio of VAcVe component in the blend. The influence of addition of VAcVe on compressive strength was studied. The results showed an improvement with a decrease in compressive strength due to the flexibility, this improvement is related to the amount of VAcVe.

The annealing treatment effects on the nanostructure of the active layer based on P3HT and PCBM and its relation to the solar cell performance was studied. The UV-visible absorption spectra and the x-ray diffraction patterns indicated enhanced crystallinity upon annealing. The AFM showed that annealing increased surface roughness and the effect is more pronounced for the higher annealing temperature. J-V characteristics of the organic solar cells showed an enhanced performance for the active layer annealed at 140 • C compared to that annealed at 80 • C with efficiencies of 2.7% and 0.31% respectively.

Here, we report a simple strategy for the preparation of graphene/TiO 2 nanocomposite by UV-assisted incorporation of TiO 2 nanosol in graphene oxide (GO) dispersion. The proposed method is facile and of low cost without using any photocatalysts or reducing agents; this can open up a new possibility for green preparation of stable graphene dispersions in large-scale production. X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy (TEM) have been used to characterize carefully the as-prepared composites and to confirm the successful preparation of the nanocomposites. The average crystallite size of TiO 2 nanoparticles calculated from XRD pattern using Rietveld analysis is ∼35 nm. TEM measurements show the adsorption of TiO 2 onto graphene (G) sheets, which prevents the restacking of graphene sheets. Current-voltage and capacitance-voltage measurements were used to investigate the electrical resistive memory properties of GO, GO/TiO 2 , and G/TiO 2 thin films. Observed results show hysteresis behavior due to the charge trapping and detrapping process, indicating that the prepared thin films exhibit an excellent resistance switching memory characteristic for G/TiO 2 device.

No abstract