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Sedghi A.,Imam khomeni International University | Miankushki H.N.,Imam khomeni International University
International Journal of Electrochemical Science | Year: 2012

Dye sensitized solar cells (DSSC) are working based on adsorbtion of photon by dye and transfer it to TiO2 electrodes. The control of microstructure and defects of TiO2 electrodes are vital for fabrication of highefficiency dye sensitized solar cells. These properties strongly related to TiO2 electrode fabrication method and its parameters. In this research the effect of different solvent, TiCl4 treatment and carbon nanotubes on microstructure and quality of nanocrystalline TiO2 electrodes were investigated. Nanocrystalline TiO2 thin films with different additives have been deposited on FTO coated glass substrates by tape casting method, then these electrodes were dried at 130°C and sintered. After that, these electrodes were immersed into a dye solution. Then cell were assembled by dye-covered TiO2 electrode, platinum coated FTO and Iodine electrolyte. The samples were characterized by FESEM, OM and the cell performance was measured by solar light simulator at an intensity of 1000 W.m-2.Best result was achieved by pre and post treatment of TiO2 electrodes by acetyl acetone and using carbon nanotube additive. ©2012 by ESG. Source


Sedghi A.,Imam khomeni International University | Miankushki H.N.,Imam khomeni International University
International Journal of Electrochemical Science | Year: 2015

Dye-sensitized solar cells (DSSC) are based on the absorption of photons by dye, and the transfer of these to TiO2 electrodes. The microstructure and defects of TiO2 electrodes are vital for the fabrication of high efficiency dye-sensitized solar cells. These properties strongly relate to the TiO2 electrode method of fabrication and its parameters. In this research, the effect of drying and thickness of the nanocrystallineTiO2 electrodes were investigated. Nanocrystalline TiO2 thin films of different thicknesses were deposited on FTO-coated glass substrates using a tape casting method. Then, these electrodes were dried at different temperatures (130°C and 70°C) at different heating rate. Subsequently, the electrodes were immersed into a dye solution. After dyeing, the cells were assembled using the dye-covered TiO2 electrodes and platinum-coated FTO and iodine electrolytes. These samples were characterized by SEM, TGA, FTIR, OM and the cell performance then measured by a solar light simulator at an intensity of 1000 W.m-2. Drying the electrodes at different temperature and different heating rate showed that the solar cells with a TiO2 electrode dried at 130°C, and at lower heating rate gave a higher short-circuit current density and open circuit voltage, with a higher overall conversion efficiency of 5.1%. The effect of the thickness of TiO2 films on the parameters of DSSCs was also investigated. Results showed that by increasing the thickness of the TiO2 films, absorption of the N719 dye through the TiO2 layers increased to a more optimum level, so that power conversion efficiency (Η) of 7.51 % was obtained. © 2015 The Authors. Source


sedghi A.,Imam khomeni International University | Miankushki H.N.,Imam khomeni International University
International Journal of Electrochemical Science | Year: 2014

The counter electrode is an important component in dye-sensitized solar cells (DSSC) where the mediator is reduced. It consists of fluorine-doped tin oxide (FTO) glass coated with platinum to afford more reversible electron transfer. In this research for increasing energy conversion efficiency of DSSC's, Multi-Walled carbon nanotubes (MWCNTs) were used in counter electrode. Three types of counter electrode (CE) were fabricated: (i) All platinum counter electrodes (Pt-CE) (ii) All Multi-Walled carbon nanotube counter electrodes (MWCNT-CE) and (iii) Mixed Platinum and Multi-Walled carbon nanotube counter electrodes (Pt-MWCNT-CE). All of counter electrodes prepared fabricated on FTO glasses and cells were assembled by these electrodes and its performance was measured by solar light simulator, their behavior were studied by cyclic voltammetry technique and their Structure were studied by SEM. Results revealed that enhanced efficiency was obtained by using the Pt-MWCNT-CE. Also by using this electrode, the energy conversion efficiency increased up to about 18% in comparison with standard DSSC's. Pt-MWCNT-CE displayed the highest catalytic activity for the reduction of tri-iodide ions and lowest transfer resistance in cyclic voltammetry tests which improves photovoltaic activity of cells. © 2014 by ESG. Source

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