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The polyol method was employed for the first time to synthesize cuprous oxide nanowires using only a precursor of Cu(II) acetate monohydrate and diethylene glycol (DEG). With careful control of the reaction temperature (190 °C), the precursor concentration (0.01−0.1 mol/L), and the reaction time (6 h), we prepared Cu2O nanowires with a diameter of approximately 20 nm and a length up to 5 μm. The nanowires were characterized by SEM, TEM, XRD, and IR spectroscopy.

Introduction Cerium dioxide (CeO,) is a rare earth oxide with high refractive index and with very sharp fundamental absorption edge. It is a semiconductor with a band gap at ~3 . 2 eV. It is a highly efficient UV absorber and is used, e.g., as an additive for glass (2 to 4% CeO,) for protecting light-sensitive materials, as coating for corrosion protection of metals, as oxidation catalyst, and recently has been proposed as counter-electrode for electrochromic devices [l, 21. Different methods have been used for the preparation of CeO, coatings, namely evaporation of cerium metal followed by oxidation [3] or reactive magnetron sputtering [1]. The sol-gel process offers a new possibility for the synthesis of oxide layers by applying the liquid precursors to a substrate by dipping, spinning, or spraying [4, 51. Processing offers advantages in controlling the microstructure of films and enables the deposition of films containing multiple cations. The sol-gel method requires also less capital to deposit large area coatings.In our work CeO, and CeO,/SnO, thin films were prepared by the sol-gel method. Their optical absorption properties, which were not reported previously, will be compared with those obtained by different other techniques. Experimental Films were prepared by the dip-coating method with a pulling speed of 10 cm/min on I T 0 glass plates (2 x 3 x 0.1 cm3) and heated at 500 "C for 5 min, with eight times repeated dipping [2].The preparation of an aqueous dispersion of hydrated oxides (sol) of CeO, and mixed CeO,/SnO, started from a solution of metal salts Ce(NH,),(NO,), and SnC1,. Precipitates were obtained by addition of NH,OH until p H = 9 was reached. After washing the precipitate in order to remove residual NHZ, C1-, NO; by bidistilled water the peptization was performed, according to a modified method described by Atkinson and Guppy [6], by addition of an equimolar quantity of HNO, (pH z 1) [5]. The colloidal sols were aged at a temperature up to 90°C for 20min, giving yellowish semi-transparent sols.Transmittance spectra, in the spectral range 0.3 to 2.5 pm, were measured with a Perkin-Elmer Lambda 9 spectrometer at resolution 2 nm. A surface profiler Alfa step 200 was used for thickness measurements (resolution z 5 nm).') Hajdrihova 19,

ZnO nanorods (length 30–150 nm) were synthesized in di(ethylene glycol) using Zn(CH3COO)2as a precursor andpara-toluene sulphonic acid, p-TSA, as an end-capping agent. Increasing the concentration of p-TSA above 0.1 M causes the reduction of the ZnO length. Nanocomposites with poly(methyl methacrylate) were prepared using unmodified nanorods. They enhanced the UV absorption of nanocomposites (∼98%) at low ZnO concentrations (0.05–0.1 wt.%), while visible light transparency was high. At concentrations of 1 wt.% and above, nanorods enhanced the thermal stability of nanocomposites. At low concentrations (0.05–0.1 wt.%), they increased the storage modulus of material and shiftedTgtowards higher temperatures as shown by dynamic mechanical analysis, DMA, while at higher concentrations (1.0 wt.%) this effect was deteriorated. DMA also showed that spherical ZnO particles have a more pronounced effect on the storage modulus andTgthan nanorods.

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