Proton-conducting gel polymer electrolytes based on gelatin plasticized with glycerol and containing acetic acid were investigated, characterized, and applied to electrochromic window. For glycerol contents varying from 7% to 48%, the conductivity of the uniform and predominantly amorphous gel electrolyte was found to follow a Vogel-Tamman-Fulcher behavior with the temperature. Typically, for the electrolyte chosen to make 7×2 cm 2 electrochromic smart window with the configuration: glass/ fluor-doped tin oxide (FTO)/WO 3 /gelatin electrolyte/CeO 2 -TiO 2 /FTO/glass and containing 28% of glycerol, the conductivities were found to be of the order of 5×10 −5 S/cm at room temperature and 3.6×10 −4 S/cm at 80°C. The device was characterized by spectroelectrochemical techniques and was tested up to 10,000 cycles showing a fast coloring/ bleaching behavior, where the coloring process was achieved in 10 s and the bleaching in 2 s. The transmission variation at the wavelength of 550 nm was about 15%. The cyclic voltammograms showed a very good reversibility of the cathodic/anodic processes, and the charge density was about 3.5 mC/cm 2 . The memory tests showed that the transmittance in the colored state increased by 8% in 90 min after removing the potential.

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This work emp loys extracts fro m Walnuts, Rhubarb, and Po megranate as natural dyes for fabricat ion of dye-sensitized solar cells (DSSCs). ZnO nanoparticles with crystallite mean value 12 n m as confirmed fro m XRD data have been synthesized at pH 12. SEM p icture of the ZnO powder reveals ho mogeneous and well defined nanoparticles with size of about 15 n m. TEM micrograph shows that the powder has a porous agglomerate structure consisting main ly of spherical crystalline particles with about 15-20 n m diameter. ZnO films were deposited on Fluorinated Tin Oxide (FTO) coated glass sheets followed by sintering at 450℃. The samples were sensitized by soaking in the dye solution. A Graphite slab was used as a back electrode, and redo x was employed as an electrolyte. Each cell was illu minated with light intensities in the range 40,000-100,000 Lux to measure the photovoltaic parameters. The experimental results shows that the highest I sc value is obtained fro m the DSSC sensitized with Rhubarb extract while the highest V oc value is obtained from the DSSC sensitized with the Walnuts extract. The P max of the DSSC sensitized by the Walnuts extract is greater than those sensitized by Rhubarb and Po megranate ext racts. Moreover, the open circuit voltage V oc decay was found to closely fo llo w a pseudo single exponential form.

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Stable crystalline aluminum doped zinc oxide (AZO) nanopowders were synthesized using hydrothermal treatment processing. Three different aluminum precursors have been used. The Al-precursors were found to affect the morphology of the obtained nanopowders. AZO nanoparticles based on zinc acetate and aluminum nitrate have been prepared with different Al/Zn molar ratios. XRD investigations revealed that all the obtained powders have single phase zincite structure with purity of about 99%. The effect of aluminum doping ratio in AZO nanoparticles (based on Al-nitrate precursor) on structure, phase composition, and particle size has been investigated. The incorporation of Al in ZnO was confirmed by UV-Vis spectroscopy revealing a blue shift due to Burstein-Moss effect.