ABSTRACT
ZnO nanopowders were prepared by the sol-gel techniques with two kinds of solvent. Microstructure of powder samples was examined by XRD and TEM. The results indicate that the two ZnO samples have the same crystal and energy band structure. Their photoluminescence (PL) spectra in ultraviolet region are analogous, but their photoluminescence (PL) spectra in visible region are different. The reason is that the two kinds of solvent with different polarity result in the difference in configuration and distribution of the sample surface states in the two systems.
Subject(s)
Luminescence , Nanoparticles/chemistry , Zinc Oxide/chemistry , Algorithms , Gels , Microscopy, Electron, Transmission , Models, Chemical , Nanoparticles/ultrastructure , Polymethyl Methacrylate , Powders , Spectrometry, Fluorescence , X-Ray DiffractionABSTRACT
A new synthesis route for preparing Dawson-type polyoxometalate (POM) based inorganic-organic hybrid materials is presented. Two new heteropolytungstate-based dimeric and oligomeric Pt(II) acetylide inorganic-organic hybrid compounds (2PtOD and PPtOD) were prepared by Hagihara's dehydrohalogenating coupling of a terminal diacetylene POM hybrid containing diphosphoryl functionality and an appropriate platinum(II) halide precursor. This method provides a rigid covalent linkage between the POM and the organometallic Pt(II) acetylide moiety. The redox potential of the polyanion can be tuned by grafting the organic and organometallic groups on it. The photoelectric properties of hybrid LB films derived from these inorganic-organic composites were studied.
Subject(s)
Organoplatinum Compounds/chemical synthesis , Tungsten Compounds/chemistry , Acetylene/chemical synthesis , Acetylene/chemistry , Dimerization , Electricity , Electrochemical Techniques , Luminescence , Models, Molecular , Organoplatinum Compounds/chemistry , Oxidation-Reduction , Photochemical Processes , Polyelectrolytes , Polymers/chemical synthesis , Polymers/chemistry , Spectrophotometry, Ultraviolet , Tungsten Compounds/chemical synthesisABSTRACT
Based on the sol-gel method, nanosized SnO2 material was prepared, and its structure and properties were studied by XRD, UV and Raman spectra. The XRD result indicated that the SnO2 particles had an ideal nanosize. The diameter of SnO2 particles increased with raising the temperature. The Raman spectrum indicated that the SnO2 nanometer material annealed at low temperature had a large number of O-empties. The UV spectra showed that the sample had stable absorption properties although the particle size changed greatly in the annealed range of 300-500 degrees C. These properties might be utilized in enhancing the performance of SnO2 gas-sensitive devices.
Subject(s)
Nanotechnology , Tin Compounds/chemical synthesis , Adsorption , Gels , Particle Size , Polymethyl Methacrylate , Spectrum Analysis, Raman , Temperature , Tin Compounds/chemistry , X-Ray DiffractionABSTRACT
High quality water-soluble semiconductor CdSe quantum dots (QDs) were prepared by a phase transfer method, in which amphiphilic oligomers (polymaleic acid aliphatic alcohol ester) was used as surface coating agents. The as-prepared aqueous QDs were high fluorescent and extremely stable. Fourier transform infrared spectroscopy, thermogravimetric analysis, and transmission electron microscopy all indicated that the surfaces of the QDs were coated with amphiphilic oligomers. Alkyl chain length of the amphiphilic oligomers could dramatically affect the phase transfer efficiency. It was found that the use of polymaleic acid n-hexadecanol ester had the best result. A biocompatible test has been carried out and such prepared water-soluble QDs were used to target tumor cells and found that the oligomer-functionalized QDs were excellent fluorescence labels for detecting the human hepatoma cells.