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This work reports on the preparation of Cr-doped TiO 2 (Cr-TiO 2 ) and its utilization in the photoanode of a dye-sensitized solar cell (DSSC). Pure TiO 2 and 10% Cr-TiO 2 sols were individually obtained via hydrolysis followed by a hydrothermal process at 250 C for 12 h. The TiO 2 sol was first coated on a fluorine-doped tin oxide (FTO) substrate using a polymer binder and sintered at 500 C for 30 min. The Cr-TiO 2 sol was then deposited on the TiO 2 layer through the same procedure, thus forming two different layers on the substrate. We found that the photovoltaic efficiency was improved by ca. 18.3% when the double layer was adopted as the photoanode of a DSSC instead of only the TiO 2 layer. We assume that this improvement was caused by the repression of electron recombination occurring in the double layer. Further characterizations were carried out to clarify the function of the double layer.

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A binary BiTe nanocompound for thermoelectric applications was prepared via a water-based chemical reaction under atmospheric conditions. We attempted to increase the carrier mobility of the nanocompound by adopting a post-thermal treatment consisting of calcination and reduction at different temperatures. We also tried to control the carrier density of the compound by adjusting the stoichiometry of the atomic constituents. We measured other transport properties (i.e., electrical resistivity, Seebeck coefficient, and thermal conductivity) and observed how these properties were affected by both the carrier mobility and the carrier density. We derived the thermoelectric performance, as captured by the figure of merit (ZT), from the transport properties and discussed the effect of such properties on the ZT value. The nanocompound exhibited a very competent ZT value (0.91 at 100 °C), which is one of the best thermoelectric performances of chemically synthesized BiTe materials.