Papers by Keyword: Dye Sensitized Solar Cell

Abstract: Dye sensitized solar cells (DSSCs) consist of photoanodes (dye adsorbed porous semiconductor film), electrolytes and counter electrodes. Nanostructured materials play important parts in both the photoanodes and the counter electrodes, while dyes are there to absorb photons and generate electron-hole pairs and electrolytes are there to transfer electrons from the photoanodes to the counter electrodes. In this study, to enhance light absorption and minimize electron-hole recombination, Ag nanoparticles and MgO nanolayer were coated on TiO₂, respectively. To enable a long lifetime, i.e. avoiding liquid electrolyte leakage, quasi-solid-state (QSS) DSSCs were fabricated. PtSn nanoparticles were prepared by a simple chemical reduction method on graphene oxide (GO) to compare with conventional Pt catalyst on FTO substrates as counter electrodes. An average efficiency of the QSS DSSCs with PtSn/GO co-catalysts was found to outperform that of the QSS DSSCs with conventional Pt catalyst. A mixed microstructure of the PtSn/GO co-catalyst was observed. Although, PtSn₂ and Pt₂Sn₃ phases were suggested by XRD, in a small region observed by EDX-STEM, it was found that C, O and Si were distributed uniformly on the graphene oxide film. Pt was also distributed uniformly, but the signal was low so there were only a few X-Ray counts across the image. There was no sign of Pt being concentrated in the particles. However, Sn was found to be concentrated in the particles without any other elements.

Abstract: Natural dyes extracted from black rice are used as sensitizer for dye sensitized solar cell. The anthocyanin extracted with various pH in acidic and neutral coditions. Preparation of fotolectrode TiO₂ film using doctor blade method and resulting average grain size 33,9 nm using X-Ray Diffractometer. Characterization of morphology and cross-section film TiO₂ is confirmed by Scanning Electron microscopy (SEM). Optical absorption using UV-Visible Spectroscopy to obtain spectrum absorbance of anthocyanin in various pH. The current-voltage (J-V) characterization shows the performance DSSC have a match relation to the optical absorption. The best absorption of anthocyanin obtained at pH 6 as well as conversion efficiency reaches 2.26% at this pH condition.

Abstract: This work focused on the electrical and Hall Effect of Organic Solar cell (OSC). In this work, Indium Tin oxide (ITO) glass as substrate was heated at 50 °C to 200 °C. The polymer used was Poly (3-Dodecylthiophene) (P3DT) thin film and Downy Rose Myrtle berries (Rhodomyrtus Tomentosa (Ait.) Hassk.) as dye. The P3DT were deposited on the ITO substrate using electrochemistry method at room temperature. While, the dye of Downy Rose Myrtle berries was deposited by layered using spin coating method. The electrical conductivity of ITO deposited thin film was explored by four point probes (FPP) under dark and under light radiation (range of 10 Wm^-2 to 200Wm^-2). From FPP study, the electrical conductivity was increased by the increment of light intensity and temperature of substrate. Lastly, the samples were examined using Hall Effect measurement to obtain the type of sample, Hall mobility, and highest charge carrier in the sample of OSC. The results show that the sample is suitable for further solar cell application.

Abstract: First-principles study based on density functional theory (DFT) framework for structural, electronic and optical properties of titanium dioxide (TiO₂) in anatase and rutile phases are investigated. Anatase phase exhibits wide band gap compare to rutile phase. The partial and total density of states for TiO₂ (anatase and rutile) describes the occupying of titanium (Ti) and oxygen (O) atoms at each energy level. TiO₂ has a high dielectric constant to avoid the recombination process while its high refractive index provides the efficient of light diffusion. The optical absorption of TiO₂ occurs in ultraviolet (UV) light of the wavelength photon. The results from the first-principles calculations will be helpful to give an understanding about the properties of TiO₂ as promising photoanode in dye-sensitized solar cell (DSSC).

Abstract: This study highlights the structural, morphological, photovoltaic and electron transport properties of zinc oxide-multi-walled carbon nanotubes (ZnO-MWCNTs) based dye-sensitized solar cell (DSSC) prepared at different concentrations of 0.0, 0.1, 0.3 and 0.5 wt.%. The ZnO-MWCNTs thin films were prepared by a chemical bath deposition method. X-ray diffraction (XRD) analysis proved the formation of hexagonal wurtzite of the samples. The crystallite sizes, D of ZnO-MWCNTs was measured varies from 21 nm to 11 nm. The oat-like ZnO nanoflakes structure and the presence of MWCNTs were captured by field-emission scanning electron microscopy (FESEM) analysis. Transmission electron microscopy (TEM) analysis measured the inner (~6.81 nm) and outer (~28.31 nm) diameter of MWCNTs. The optimum concentration of 0.1 wt.% MWCNTs produced the highest photocurrent density, J_sc of 13.5 mA/cm², open-circuit voltage, V_oc of 0.149 V, fill factor, FF of 0.406 and power conversion efficiency, PCE of 0.817 %. Optimum doping of 0.1 wt.% MWCNTs generated short electron lifetime, τ_eff of 0.67 ms, low effective electron chemical diffusion coefficient, D_eff of 9.5 x 10^-8 cm² s^-1 and higher electron recombination rate, k_eff of 1497.48 s^-1. The addition of MWCNTs has influenced the structural, morphological, photovoltaic and electron transport properties of ZnO-MWCNTs based DSSC.

Abstract: Titanium dioxide (TiO₂) is a well-known promising photocatalyst that has been used as the photoanode in dye sensitized solar cells (DSSC). Since graphene has good electrical, mechanical and chemical properties, its use is supposed to enhance the photocatalytic activity of TiO₂, the absorption of dye and enhance the mechanical strength of the layers of DSSC. There are several methods of preparing TiO₂/graphene composite using complicated process and high-tech instruments. In this study, TiO₂/graphene nanocomposite was prepared using two facile methods, which is achieved by mixing graphene oxide (GO) sheets with commercially available TiO₂ paste and the other method was based on thermal reaction of mixed TiO₂ and GO before incorporating it to the working electrode of DSSC. The quality of GO reduction in the process of making the composite was characterized by using FTIR spectra and Raman spectroscopy.

Abstract: Impedance spectroscopy (IS) is a useful technique to investigate the detail of charge transfer in dye sensitized solar cell (DSSC) especially for individual part of cell component. The charge transport in electrolyte, platinum and TiO₂ electrodes can be separately examined by varying the frequency range of IS. In this work, the TiO₂ electrode was modified by various nanostructures and the equivalence circuit parameters extracted from the measured IS were correlated to the power conversion efficiency of fabricated solar cells, in order to describe the origin of decreasing and increasing of the DSSC efficiency. The TiO₂ electrode was prepared at different conditions of mixing with inorganic nanoparticle of CdS, CdSe and nanostructure of C₆₀ at various concentration. Normally, the DSSC with unmodified TiO₂ electrode shows the efficiency about 7.12% at AM 1.5. The dramatically dropping of efficiency was occurred in the cell with very small amount of nanoparticle added in TiO₂ electrode. For most of the cases, the efficiency tended to become increase as increasing the amount of nanoparticle in the TiO₂ electrode. In some structures, the efficiency can become higher than that of the unmodified TiO₂ cell. However the large amount of nanoparticle in TiO₂ electrode leaded to decreasing of cell efficiency in all fabricated types of TiO₂ nanostructure. These efficiency variations were related to the resistance and capacitance values extracted from IS measurement in the frequency range of TiO₂ response. It was found that the extracted value of cell resistance played the important role on the efficiency variation and the capacitance value can be used to describe the life-time of charge carrier in the cells.Keywords: Impedance spectroscopy, dye sensitized solar cell.

Abstract: Water based Remazol Brilliant Red, Orange and Violet dyes were used as the dye sensitizer in dye-sensitized solar cell. The performance of the solar cell was investigated between the dye concentrations, 0.25 mM and 2.5 mM and three different soaking times which at 3 hours, 12 hours and 24 hours. The adsorption peaks of the dyes were observed using ultraviolet-visible-near infrared (UV-Vis-NIR) Spectrometer and the performance of the dye-sensitized solar cell was measured using Spectrum Parameter Analyzer (SPA). The results show that the device efficiency was increased with dye concentration, but, the DSSC performance at different soaking times performed differently with the previous study. The highest conversion efficiency of 1.125 % was obtained for Remazol Brilliant Red at concentration of 2.5 mM at 3 hours soaking time.