Papers by Keyword: Organic/Inorganic

Abstract: A perylenetetracarboxylic diimide derivative, N,N,N′,N′-tetra(hydroxyethyl)-1,7-di (4-tert-butylphenol)perylene-3,4:9,10-tetracarboxylic diimide(THPDI), was synthesized and covalently self-assembled as a monolayer on the modified a quartz surface. UV-vis absorption and IR spectra revealed the H-aggregate nature of THPDI molecules in the obtained thin solid film. With this thin solid film as a template, CdS nanoparticles were deposited on it in situ, which were characterized by electronic absorption, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The morphology of CdS nanoparticles is disklike, and the diameter is ca. 150 nm as determined by AFM. The present result provides an effective and new method toward directed growth of specific morphologies of the nanoparticles. It is believed helpful for designing and preparing molecular-based nano-electronic and nano-optoelectronic devices with good performance.

Abstract: Organic-inorganic photovoltaic systems which attempt to integrate benefits of both material types in terms of ease of fabrication, stability and efficiency are reviewed. Three broad categories; inorganic-small molecule systems, carbon naotube incorporated organic photovoltaics and nanostructured organic surfaces-based photovoltaics have been discussed with reference to recent literature. Nanocrystal-organic systems are designed to improve broadband photon collection possibilty, nanostructred organic surfaces-based systems attempt to enhance exciton dissociation at the increased area interface. Incorporation of carbon nanotubes in donor-acceptor type photovoltaic systems have been shown as a technique to mitigate drawbacks from short carrier diffusion lengths of organic materials. The concepts present new opportunities for complex photovoltaic systems, which need to be cheap, large area and efficient in order to arrive at an economically viable level for mass uptake.

Abstract: This paper focuses on the preparation of siloxane-polyurethane hybrid materials using a sol-gel method. The global aim of the project is to tailor mechanical properties, degradability rate, bioactivity and biocompatibility to design scaffolds for musculoskeletal applications. A series of seven hybrid materials were synthesized with varying the proportion of polydimethylsiloxane (PDMS), and Polyurethane (PU). The organic part ratios (by weight) employed were (% PDMS:% PU) 30:0, 35:5, 20:10, 15:15, 10:20, 5:25, and 0:30. The organic part was reacted with constant 70 % TEOS to obtain the hybrid materials. A sol-gel process was selected for the synthesis of the hybrids. The characterization of materials was carried out by the fourier-infrared spectroscopy (FT-IR), x-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electronic microscopy (SEM) and proton nuclear magnetic resonance (1H-NMR) techniques in order to analyze the structure, microstructure and chemical composition of the hybrid materials. Gelification time depends on the proportion of PU used. When no PU is employed, the gel time is 8 hours but it rises up to 18 days for 30 % of polyurethane. Materials range from opaque to translucent but with a greater fragility for greater amounts of polyurethane. No differences in the bonding of materials could be appreciated.

Abstract: Hybrid organic-inorganic materials were fabricated using sol-gel technique using poly(methyl methacrylate) and methacrylic acid 3-(trimethoxysilyl)propyl ester (MAMSE) with 90/10, 80/20 and 70/30 (%w/w) ratios with tetrahydrofuran (THF) solvent. The thin films were then characterized using FTIR spectra, SEM, DSC and TGA thermograms. From the preliminary characterization, the hybrid material was found to have nano and ultra scale tight pore ranges. FT-IR spectroscopy uncovered all the signature peaks characteristic of silicate structures in the near-surface regions. Fingerprints of Si-O-Si groups in cyclic and linear molecular substructures are present. The SEM image clearly shows that hybrid materials have homogenous and smooth surface. DSC analysis of the material shows interesting phenomenon regarding glass transition temperature (Tg). The hybrid material was found to have higher Tg than pure PMMA. From TGA analysis, the hybrid materials were observed to have higher thermal stability than pure PMMA.