Dye Sensitized Solar Cells

The present article reports on the enhancement of the performance and stability of natural dye-based dye-sensitized solar cells (DSSCs). Natural dyes extracted from papaya leaves (PL) were investigated as sensitizers in TiO2-based DSSCs and evaluated in comparison with N719 dye. The acidity of the papaya-leaf extract dyes was tuned by adding benzoic acid. The TiO2 film-coated fluorine-doped tin oxide glass substrates were prepared using the doctor-blade method, followed by sintering at 450°C. The counter electrode was coated by chemically deposited catalytic platinum. The working electrodes were immersed in N719 dye and papaya dye solutions with concentrations of 8g/100mL. The absorbance spectra of the dyes were obtained by ultra-violet-visible spectroscopy. The energy levels of the dyes were measured by the method of cyclic voltammetry. In addition, Fourier transform infrared spectroscopy was used to determine the characteristic functionalities of the dye molecules. The DSSC based on the N719 dye displayed a highest efficiency of 0.87% whereas those based on papaya-leaf dye achieved 0.28% at pH 3.5. The observed improved efficiency of the latter was attributed to the increased current density value. Furthermore, the DSSCs based on papaya-leaf dye with pH 3.5-4 exhibited better stability than those based on N719 dye. However, further studies are required to improve the current density and stability of natural dye-based DSSCs, including the investigation of alternative dye extraction routes, such as isolating the pure chlorophyll from papaya leaves and stabilizing it.

ABSTRACT Cobalt-based electrolytes are highly tunable and have pushed the limits of dye-sensitized solar cells, enabling higher open-circuit voltages and new record efficiencies. However, the performance of these electrolytes and a range of other electrolytes suffer from slow electron transfer at platinum counter electrodes. High surface area platinum would enhance catalysis, but pure platinum structures are too expensive in practice. Here, a material-efficient host-guest architecture is developed that uses an ultrathin layer of platinum deposited upon an electrically conductive scaffold, niobium-doped tin oxide (NTO). This nanostructured composite enhances the counter electrode performance of dye-sensitized solar cells (DSCs) using a Co(II/III)BPY3 electrolyte with an increased fill factor and power conversion efficiency (11.26%), compared to analogous flat films. The modular strategy is elaborated by integrating a light scattering layer onto the counter electrode to reflect unabsorbed light back to the photoanode to improve the short-circuit current density and power conversion efficiency.

Dye-sensitized solar cells (DSSCs) fabricated using nanocrystalline SnO2 films sensitized by the Ru (dcbpy)(NCS) 2 dye (N3) were compared to the corresponding nanocrystalline titania cells. Although the light-to-power energy conversion efficiency of SnO2 cells is low ...

Dye-sensitized solar cells (DSSCs) have tremendous attention as a promising photovoltaic cell due to their cost effective performance, simple fabrication process and environmental friendliness. In this work carbon layered counter electrode and nanostructured TiO2 (Degusa P-25) photoanode were used as two electrodes of the DSSC respectively and turmeric (Curcuma longa) natural dye was used as photo sensitizer. TiO2 paste was deposited on ITO glass substrate by using doctor blade technique, annealed at 450 Deg C for 1 hour to obtain the nano-structured coating surface. A very smooth as well as nano porous TiO2 photoanode coating surface was observed from the morphological studies of surface profilometer, inverted microscope and scanning electron microscopy (SEM) analysis. The dye was extracted by using various solvent like methanol, ethanol, acetone, hot distilled water, normal distilled water etc. and was characterized from UV-Vis spectroscopy and FTIR data analysis. In this experiment tip of candle flame film was found as optimized catalyst materials. Good cell performance was found when dry turmeric was used as dye source, extracted by ethanol solvent in self extraction process and 2 hours socking the TiO2 photoanode with extracted dye. DSSC performance was determined from an experimental setup by varying the load resistance. In optimized condition Voc, Isc, power density, fill factor and efficiency were 566 mV, 1.02 mA/cm2, 0.45 mW/cm2, 0.78 and 0.45% respectively.

The performance of dye sensitized solar cells (DSSCs), sensitized with natural pigments extracted from mango (mangifera indica), carica papaya, moringa oleifera leaves and bougainvillea flower was demonstrated. The photoactive electrodes of the various DSSCs were sensitized with aqueous extract of the natural pigments. The resulting photoelectrodes were successfully incorporated into the DSSCs. The photoelectrochemical perfomance of the DSSCs were evaluated under 100 mAcm-2 light intensity with open circuit voltage (V OC) ranging from 0.36 to 0.49 V and short circuit current density (J SC) ranging from 0.0134 to 0.1314 mAcm-2. From the photovoltaic performance of the extracts, the Mangifera Indica extract sensitized solar cell gave the best performance with J sc of 0.1314 mAcm-2 , V oc of 0.49 V, a fill factor (FF) of 0.59, and an overall solar energy conversion efficiency (η) of 0.038%. The sensitization performance related to the interaction between the dye and TiO 2 surface is discussed.