Wide Band Gap Transparent Polymer-Inorganic Composite Thin Films by Dip-Coating Method: Preparation and Characterizations

Wide band gap transparent polymer-inorganic (PVA-ZnO) composite thin films were prepared by the dip-coating method. Functional groups and metal oxide vibrations were found from Fourier transform-infrared spectroscopy. The elements Zn and O were confirmed from energy dispersive X-ray spectroscopy. The X-ray diffraction patterns revealed that the sharp diffraction peaks correspond to the hexagonal wurtzite structure of ZnO in the PVA matrix. Scanning electron microscopy images showed that the ZnO nanoparticles are randomly distributed throughout the entire film surface. The optical study reveals that the transmittance was more than 85% with very low absorption and wide band gap energy (4.03 to 3.95 eV). The obtained results indicate that the high transmittance, very low absorption, and wide band gap energy of the prepared dip-coated composite thin films make them suitable for use in transparent optoelectronic device applications in the near future.     

Nano-electrocatalyst materials for low temperature fuel cells:A review

Low temperature fuel cells are an attractive technology for transportation and residential applica‐tions due to their quick start up and shut down capabilities. This review analyzed the current status ...     

Synthesis,growth and characterization of single crystals of pure and thiourea doped L‐glutamic acid hydrochloride

L(+)Glutamic acid hydrochloride [HOOC (CH₂)₂CH(NH₂) COOH·HCl], a monoamino dicarboxylic acid salt of L‐Glutamic acid was synthesized and the synthesis was confirmed by FTIR analysis. Solubility of the material in water was determined. Pure and Thiourea doped L‐Glutamic acid hydrochloride crystals were grown by low temperature solution growth using solvent evaporation technique. XRD, UV‐Vis‐NIR analyses were carried out for both pure and thiourea doped crystals. The crystals were qualitatively analyzed by EDAX analysis and the presence of thiourea was confirmed. The cell parameters of L‐Glutamic acid hydrochloride have been determined as a = 5.151 Å, b = 11.79 Å, c = 13.35 Å by X‐ray diffraction analysis and it crystallizes in orthorhombic space group P2₁2₁2₁. UV‐Vis‐NIR spectra analysis showed good optical transmission in the entire visible region for both pure and doped crystals. Micro hardness of both pure and doped crystals has been determined using Vickers micro hardness tester. The SHG efficiencies of both pure and doped crystals were determined using Kurtz powder test and pure L‐Glutamic acid hydrochloride crystal was found to possess better efficiency than thiourea doped L‐Glutamic acid hydrochloride crystals. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)