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Abstract: A thin compact layer of TiO2 deposited on the conductive transparent substrate of a dye-sensitized solar cell photoanode, (blocking layer, BL) can enhance the performances of the entire device. In this paper, an optimized spin coating process using an alcoholic TiCl4 solution was developed and correlated to the final properties of the layer. The physicochemical characteristics of the precursor solution and the spin coating parameters were optimised to obtain a uniform layer. XRD, FE-SEM, UV–Vis spectroscopy, AFM, cyclic voltammetry and electrochemical impedance spectroscopy were used to evaluate the influence of the number of deposition cycles on the TiO2 layer. The results were compared with those obtained using a conventional dip coating technique, showing that the newly developed spin coating process produces blocking layers with superior properties. Finally, analyses of the photovoltaic performances of the complete cell confirmed that an optimized blocking layer can lead to an improvement of the solar conversion efficiency of about 84%. [Copyright &y& Elsevier]

Abstract: Sub-micrometer powder (100–150nm diameter) of Yb-doped yttrium oxide was obtained, for the first time, by microwave-assisted polyol (diethylene glycol, DEG) method. This method is based on fast and homogeneous increase of temperature, due to the microwave heating, and on addition of the hydrolysing agent (water) at high temperature. This promotes a fast nucleation followed by a controlled growth of nuclei. Different procedures were used to process the as-synthesized powders. In some cases washing by ultrapure water was used to dissolve nitrate and DEG by-products, this treatment allowed the use of a lower calcination temperature (150–200°C less) to obtain the crystalline phase. Analysis of the calcined powder showed different levels of structures: from nanocrystal (10–15nm), to primary particles (100–150nm), to micrometer soft aggregates (2–4μm). The microwave-assisted polyol method resulted an easy way to dope yttria with the desired amount of Yb3+. This work was carried out in order to prepare particles to be used as rare-earth doped Y2O3 and YAG polycrystalline transparent ceramic for laser source applications. [Copyright &y& Elsevier]