Thermoelectricity Based on Cuo as a Semiconducting Material

In this paper, thermoelectricity based on copper(II) oxide CuO as semiconducting material is explored. The electrical properties of the samples were studied under different temperature gradients and pressures. Moreover, the effect of baking temperature was also investigated. CuO prepared using decomposition of Cu(NO3)2 as well as CuO nanopowder prepared using microwave-assisted synthesis technique were investigated and their results were compared. It was found that the current density can be enhanced with increasing the pressing pressure of the sample and when the sample undergoes a baking process. Moreover, it was found that the current density can be considerably enhanced with increasing the temperature gradient between the two ends of the sample. The CuO prepared using microwave-assisted synthesis technique was found to exhibit much better results over those of the CuO prepared using decomposition of Cu(NO3)2

Aldimine derivatives as photosensitizers for dye-sensitized solar cells

Five aldimine derivatives were prepared by condensation of the appropriate amine with salicylaldehyde (m1-m4) and 4-aminobenzoic acid with 2-thiophene carboxaldehyde (m5). A molar ratio of 1: 1 was used and the mixture was refluxed in ethanol for 2 h to obtain the corresponding aldimine derivative. These derivatives were used as photosensitizers for dye-sensitized solar cells (DSSCs). The best performance was obtained for the DSSC sensitized with 2-(2-hydroxybenzylideneamino) benzoic acid, for which a short-circuit current of 2.86 mA/cm^ 2, an open-circuit voltage of 0.562 V, and an efficiency of 0.575% were obtained.Five aldimine derivatives were prepared by condensation of the appropriate amine with salicylaldehyde (m1-m4) and 4-aminobenzoic acid with 2-thiophene carboxaldehyde (m5). A molar ratio of 1: 1 was used and the mixture was refluxed in ethanol for 2 h to obtain the corresponding aldimine derivative. These derivatives were used as photosensitizers for dye-sensitized solar cells (DSSCs). The best performance was obtained for the DSSC sensitized with 2-(2-hydroxybenzylideneamino) benzoic acid, for which a short-circuit current of 2.86 mA/cm^ 2, an open-circuit voltage of 0.562 V, and an efficiency of 0.575% were obtained

Natural Dyes as Photosensitizers for Dye-sensitized Solar Cells

Dye-sensitized solar cells (DSSCs) were assembled using Zinc oxide (ZnO) nanoparticles as a photoelectrode and natural dyes extracted from eight natural plants as photosensitizers. The structural properties of the synthesized ZnO nanoparticles were studied using XRD, SEM and TEM characterizations. Photovoltaic parameters such as short circuit current density Jsc, open circuit voltage Voc, fill factor FF, and overall conversion efficiency η for the fabricated cells were determined under 100 mW/cm2 illumination. It was found that the DSSC fabricated with the extracted safflower dye as a sensitizer showed the best performance. Also, its performance increased with increasing the sintering temperature of the semiconductor electrode with highest performance at 400 °C. Moreover, it was found that a semiconductor electrode of 7.5 μm thickness yielded the highest response

Dyes Extracted from Safflower, Medicago Sativa, and Ros Marinus Oficinalis as Photosensitizers for Dye-sensitized Solar Cells

In this work, three extracts of plant leaves were used as sensitizers for dye-sensitized solar cells (DSSCs). These plants are Safflower, Medicago sativa and Ros marinus oficinalis. The natural dyes were extracted before and after grinding the plant leaves. The UV-VIS absorption spectra of the three extracts in ethyl alcohol solution were measured. The DSSCs were assembled using TiO2 films on Fluorine-doped tin oxide (FTO) coated glass. The DSSCs sensitized with the extracts of grinded leaves showed a better performance compared to those sensitized with un-grinded leaves with the highest efficiency of 0.115 % was obtained for the DSSC sensitized with Medicago sativa. The performance of the DSSCs sensitized with Safflower and Ros marinus oficinalis was significantly improved by acid treatment of the FTO substrates. Impedance spectroscopy of the fabricated cells was also carried out

الخلايا الشمسية ذات الاصباغ باستخدام اكسيد الزنك كطبقة شبه موصلة

Dye-sensitized solar cell (DSSC) was developed by Grätzel in 1991 which was named "Grätzel Cell". DSSC is considered the third generation of photovoltaic devices for the conversion of visible light into electric energy. These new types of solar cells are based on the photosensitization produced by the dyes on wide band-gap semiconductors such as TiO2. This sensitization is produced by the dye absorption of part of the visible light spectrum. One advantage of DSSCs is the low cost of the solar energy conversion into electricity because of inexpensive materials and the relative ease of the fabrication processes. Recent studies have shown that metal oxides such as TiO2, have been successfully used as photo-anode when a dye is absorbed in the interior of the porous layer of the semiconductor. In this work, DSSCs were prepared using Zinc oxide (ZnO) as a semiconducting layer with eight natural and eight chemical dyes. Thin films of nanocrystalline ZnO was spread on transparent conducting FTO coated glass using doctor blade method. The absorption spectra of all dyes were performed. The I-V characteristic curves of the fabricated cells were measured and studied at different light intensity. All photovoltaic parameters of the cells were defined. The results revealed that the extract of safflower and Eosin Y corresponds to the highest efficiency. Optimization of the fabricated cells were conducted concerning the sintering temperature and the thickness of the ZnO layer

Dyes Extracted from Safflower, Medicago Sativa, and Ros Marinus Oficinalis as Photosensitizers for Dye-sensitized Solar Cells

In this work, three extracts of plant leaves were used as sensitizers for dye-sensitized solar cells (DSSCs). These plants are Safflower, Medicago sativa and Ros marinus oficinalis. The natural dyes were extracted before and after grinding the plant leaves. The UV-VIS absorption spectra of the three extracts in ethyl alcohol solution were measured. The DSSCs were assembled using TiO2 films on Fluorine-doped tin oxide (FTO) coated glass. The DSSCs sensitized with the extracts of grinded leaves showed a better performance compared to those sensitized with un-grinded leaves with the highest efficiency of 0.115 % was obtained for the DSSC sensitized with Medicago sativa. The performance of the DSSCs sensitized with Safflower and Ros marinus oficinalis was significantly improved by acid treatment of the FTO substrates. Impedance spectroscopy of the fabricated cells was also carried out

Dyes Extracted From the Seeds of Eruca Sativa, Nigella Sativa and Ammi Visnaga as Photosensitizers for Dye-Sensitized Solar Cells

In this work, the extracts of three natural dyes obtained from the seeds of Eruca Sativa, Nigella sativa, and Ammi visnaga were used as photosensitizers for dye-sensitized solar cells (DSSCs). Dye Extraction was carried out before and after grinding the plant seeds. TiO2 nanopowder was used as a semiconducting material. The UV-Vis absorption spectra of the extracts of the seeds of Eruca Sativa, Nigella sativa, and Ammi visnaga in ethyl alcohol solution and the current-voltage characteristic curves of the fabricated DSSCs were measured. The energy gaps of the extracted dyes were estimated. The best response was obtained for the DSSC sensitized with Ammi visnaga with an efficiency of 0.107% before grinding the raw material and 0.132% after grinding. The acidic treatment of FTO glass sheets with HNO3 improved the efficiency by 123%, 108% and 105% for the three extracts of Eruca Sativa, Nigella sativa and Ammi visnaga, respectively