Ammonia-free chemical bath deposition of nanocrystalline ZnS thin film buffer layer for solar cells

In this work, we prepared zinc sulfide thin films on glass substrates by ammonia-free chemical bath deposition method using thioacetamide as the sulfide source and Ethylene Diamine Tetra Acetic Acid disodium salt as the complexing agent in a solution of pH = 6.0. Thin films of ZnS with different thicknesses of 18–450 nm were prepared. The effect of film thickness and annealing temperature in atmospheric air, on optical properties, band gap energy and grain size of nanocrystals were studied. The X-ray diffraction analysis showed a cubic zinc blend structure and a diameter of about 2–5 nm for ZnS nanocrystals. The Fourier Transform Infrared spectrum of films revealed no peaks due to impurities. The as-deposited ZnS films had more than 70% transmittance in the visible region. The direct band gap of as-deposited films ranged from 3.68 to 3.78 eV and those of annealed films varied from 3.60 to 3.70 eV.     

Decoration of multi-walled carbon nanotubes with silver nanoparticles and investigation on its colloid stability

In this paper, multi-walled carbon nanotubes (MWCNTs) were decorated with silver nanoparticles which have been successfully synthesized by chemical reduction of Ag cations on the acid treated MWCNTs surface by sodium hydroxide. Ag/MWCNTs were characterized by TEM and XRD. The results indicated that silver nanoparticles were homogeneously dispersed on the outer surface of MWCNTs. The dispersibility of pristine, acid treated and decorated carbon nanotubes in distilled water were investigated by zeta potential and optical image. The results revealed that the dispersion of acid treated carbon nanotubes in distilled water was better than those of pristine MWCNTs and Ag/MWCNTs.     

Calcium phosphate porous pellets as drug delivery systems: Effect of drug carrier composition on drug loading and in vitro release

Drug loaded porous calcium phosphate bone substitutes are studied for targeted drug delivery applications. In this study, porous hydroxyapatite and beta-tricalcium phosphate pellets were investigated as anti-inflammatory drug carriers and their ibuprofen adsorption and release properties were compared. While the adsorption equilibrium time of 1 h was obtained for both pellets, hydroxyapatite pellets showed a higher adsorption capacity than beta-tricalcium phosphate. The physico-chemical characterisations of loaded pellets confirmed an ibuprofen reversible physisorption on both hydroxyapatite and beta-tricalcium phosphate pellets. Moreover, higher adsorption capacity of hydroxyapatite was attributed to their physical differences. The in vitro ibuprofen release evaluation showed 100% release of ibuprofen from both hydroxyapatite and beta-tricalcium phosphate pellets which was found to be compatible with the obtained interactions between the pellets and ibuprofen.     

Hardystonite/palladium nanocomposite as a high performance catalyst for electrochemical hydrogen storage and Cr(VI) reduction

In this work, the catalytic performance of hardystonite/palladium nanocomposite (HT/Pd) for hydrogen evolution reaction (HER) and reduction of organic pollutants in water has been studied. For this purpose, palladium nanoparticles (Pd NPs) were synthesized by laser ablation in liquid (LAL) method in different concentrations and decorated on hardystonite substrate using a simple method. HT/Pd nanocomposite was characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and Brunauer-Emmett-Teller (BET) analyses. The prepared nanocomposites were coated on a stainless steel mesh and their HER activity was investigated using cyclic voltammetry (CV). The results indicated that HT/Pd catalyst had good HER performance and capability of hydrogen storage. Moreover, HT/Pd nanocomposite with high surface area exhibited excellent catalytic activity in Cr(VI) reduction within 2.5 min.     

The optical properties of PVA/TiO2 composite nanofibers

The electrospun nanofibers emerge several advantages because of extremely high specific surface area and small pore size. This work studies the effect of PVA nanofibers diameter and nano‐sized TiO₂ on optical properties as reflectivity of light and color of a nanostructure assembly consisting polyvinyl alcohol and titanium dioxide (PVA/TiO₂) composite nanofibers prepared by electrospinning technique. The PVA/TiO₂ composite spinning solution was prepared through incorporation of TiO₂ nanoparticles as inorganic optical filler in polyvinyl alcohol (PVA) solution as an organic substrate using the ultrasonication method. The morphological and optical properties of collected composites nanofibers were highlighted using scanning electron microscopy (SEM) and reflective spectrophotometer (RS). The reflectance spectra indicated the less reflectance and lightness of composite with higher nanofiber diameter. Also, the reflectance and lightness of nanofibers decreased with increasing nano‐TiO₂ concentration. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013