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ZnO has been electrodeposited from 0.5 M Zn(NO3)2 at pH 4.5 with and without polyethylene glycol (PEG) as additive. Cyclic voltammetry on FTO substrates reveals two electrochemical regimes, where reduction of nitrate and water are rate determining, respectively. ZnO films were galvanostatically electrodeposited as a function of the deposition current density: at low current densities, where nitrate reduction is rate determining, highly crystalline ZnO films were obtained, whereas amorphous ZnO films were obtained at higher current densities, where water reduction dominates. The amorphous films transform to crystalline ZnO upon sintering, and SEM images show that the presence of PEG results in a homogeneous film morphology. The films were used for the fabrication of dye-sensitized solar cells (DSSCs), resulting in solar cell conversion efficiencies of up to 1.4% for non-sintered ZnO films deposited at low current density (without PEG), while the best cells were obtained with films electrodeposited from the plating bath with 0.15 mM PEG with efficiencies of up to 1.8% for sintered films prepared at higher current density. These results illustrate that the presence of PEG in the plating bath optimizes the film morphology and, hence, the performance of ZnO-based dye-sensitized solar cells.

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In this work, it is shown the feasibility for obtaining silver nanoparticles by ultrasonic spray pyrolysis and their simultaneous incorporation during deposition of thin layers of aluminum oxide to get a Cermet coating of Al2O3-Ag. The synthesis of these Cermets was achieved on the basis of both the simultaneous pyrolysis of silver nitrate and aluminum acetylacetonate on different substrates: Quartz, glass, crystalline silicon (c-Si), and titanium at temperatures of 500, 550 and 600• C. The structural properties of the Cermets were studied by ScanningElectron Microscopy, Atomic Force Microscopy and X-ray diffraction. For the optical properties, UV-vis spectroscopy was used to obtain the optical Absorbance of the Cermets, while the Reflectance was obtained by UV-vis-IR spectroscopy measurements. UV-Vis spectroscopy showed that the intensity of the absorption peak (plasmon) was limited to the concentration of silver nitrate, and it shifted toward shorter wavelengths with the decrease in the size of the Ag nanoparticles inside the Cermets. The plasmon position of Ag nanoparticles in the different samples was found to be centered at 504 nm, 506 nm, 497 nm and 475 nm for samples deposited with 0.1 mol, 0.05 mol, 0.02 mol, and 0.01 mol of Ag(NO 3 ), respectively. The shape of the Ag nanoparticles was approximately spherical, ranging from 4 nm to 35 nm, and their concentration was proportional to the concentration of Ag(NO3) included in the spray solution. By means of the UV-Vis Spectroscopy-IR and FT-IR, in the best of cases, a solar absorptance of 0.83 and an infrared thermal emittance of 0.14, for a sample of Al2O3-Ag prepared with 0.1 mol of Ag(NO 3 ) in the precursor solution, were obtained.

An Au/Cu2Te/CdTe/CdS/TCO/glass heterostructure based superstrate solar cells with 2.5 mm2of area, where the CdTe layer was prepared by means of closed spaced sublimation (CSS) and the CdS by chemical bath, reached an efficiencyηvalue of 12.1%. As transparent conductive oxide (TCO), a thin film of cadmium-indium oxide (CdIn2O4:CIO), obtained by sol-gel technique, was used. A systematic optimization of the thermal activation of the CdTe/CdS/CIO central part of the device with a CdCl2vapor ambient made the conversion efficiency of the Au/Cu2Te/CdTe/CdS/CIO/glass heterostructure reaches 9.94% for the CdTe layer with thickness of 1.8 μm. This efficiency was reached only through an open circuit voltageVOCoptimization. A maximumηof 12.1% was reached with the established procedure of optimization and when the CdTe layer thickness was increased to 3.1 ± 0.05 μm. The substitution of CIO by commercial ITO provoked in the cell a decrease ofηfrom 12.1% to 7.2%, both devices prepared under the same conditions. Starting from these results, we can say that CIO was a better TCO than commercial ITO in our solar cell, with the advantage that CIO was obtained by sol-gel, which is a simple and economical technique.