Rajesh Cheruku

Application of CBZ dimer, C343 and SQ dye as photosensitizers for pn-tandem DSCs

A pn-tandem dye-sensitized solar cell (pn-DSC) was prepared with three different sensitized dyes CBZ Dimer (CBZD), C343, and SQ in two different compartments of the n-type or p-type cells. The constructed tandem solar cell was exhibited considerable improvement in experimental pn-DSCs parameters, open-circuit voltage, short-circuit current, fill factor, etc. These results were achieved under air mass 1.5 illumination with three different sensitized dyes in the upper and lower compartment of the pn-DSCs. These results demonstrate a complementary absorption among the two photoelectrodes in the pn-DSCs is a good approach to the efficient and low cost pn-DSCs.

Enhanced photovoltaic and carrier collection efficiency of dye sensitized solar cell: Nb2O5 coated TiO2 photoanode

ABSTRACT Dye sensitized solar cells (DSSCs) were fabricated using Nb2O5 energy barrier layer is coated on the TiO2 photoanode. This energy barrier (Nb2O5 layer) reduces the recombination rate of the photoinjected electrons with their counter holes. A monoclinic Nb2O5 energy barrier layer can be coated 1 and 3 times on a TiO2 photoanode using a dip-coating method. The Nb2O5/TiO2 photoanode exhibits enhanced photovoltaic performance, which is better than the bare TiO2 photoanode. The results presented in this study show that this Nb2O5 layer forms an inherent energy barrier at the electrode-electrolyte interface. The electron transport and charge recombination behaviors of DSSCs were investigated by electrochemical impedance spectra (EIS) and the results illustrated that the DSSCs showed the lowest charge transport resistance and the longest electron lifetime. The electron transport and recombination were studied by stepped light- induced transient measurements of photocurrent and voltage (SLIM-PCV) method and shown that the electron diffusion length is increasing with the Nb2O5 coating.

Improved performance of P -type DSCs with a compact blocking layer coated by different thicknesses

The introduction of different thicknesses of a compact NiO blocking layer coating with different spin speeds on FTO and followed by a coating of photoactive NiO electrode for p-type dye-sensitized solar cells (p-DSCs). This study examined the fabrication of a compact NiO blocking layer by decomposing an ethanolic precursor solution of nickel acetate tetrahydrate. The DCBZ dye used as the photosensitizer for the NiO electrode in the p-DSCs device and their performances have been analyzed. The enhancement of photovoltaic performance and resulted from an increase in the power conversion efficiency (η). The electrochemical impedance spectroscopy (EIS) measurement demonstrated that charge recombination was suppressed when a compact NiO blocking layer was applied. The results showed that the best p-DSC was achieved by employing 3000 rpm spin-coated process for different times of blocking layer.

The Effect of Difference Molar Ratios of Dibromo-EDOT as Hole Transporting Material for Solid State Dye-Sensitized Solar Cells

The dye-sensitized solar cells (DSSCs) are one of the promising organic photovoltaic cells due to their low cost, flexibility, and relatively good efficiency. Nevertheless, utilization of liquid electrolyte in DSSCs brings practical problems for commercialization, which leads to solid-state dye-sensitized solar cells (ssDSSCs), that based on organic conducting polymers or inorganic p-type semiconductors as hole transport materials (HTM). A one-side ssDSSCs fabricated here, with a conductive polymer Dibromo-EDOT as an HTM, and also check ssDSSCs efficiency by variation of the HTM concentrations. The morphology of cells examined through SEM, and intensity-modulated photocurrent/voltage spectroscopy, measurements were used to elucidating the electrochemical properties of ssDSSCs. We also optimize the blocking layer thickness and different molar ratios of HTM for the best efficient ssDSSCs.

Effect of electrolyte redox potentials on the photovoltaic performance in dye-sensitized solar cells based on porphyrin dye

ABSTRACT We have investigated the effect of two different kinds of cobalt electrolytes on the photovoltaic performance in dye-sensitized solar cells (DSSCs) using the established porphyrin dye (YD-2). We have characterized the photovoltaic performance of DSSCs containing iodide/triiodide and two different Co3+/2+ electrolytes to confirm the relationship between redox potential of cobalt(III/II) tris(2,2′-bipridine), [Co(bpy)3]3+/2+, cobalt(III/II) tris(1,10-phenanthroline), [Co(phen)3]3+/2+ and the photovoltaic characteristics in DSSCs. Compared to the iodine-based electrolyte, the photovoltage of the DSSCs based on [Co(phen)3]3+/2+ was increased by 15%. The current densities in [Co(bpy)3]3+/2+ and [Co(phen)3]3+/2+-based devices decrease due to their larger size and decrease in difference bewteen HOMO level of dye and redox potential of electrolytes.

Improved performance of dye-sensitized solar cells based on solution treated PEDOT as efficient counter electrode

ABSTRACT The dye-sensitized solar cell (DSSC) is a promising alternative to the Si solar cell because of its low-cost and easy fabrication. The conductive polymer counter electrode, PEDOT has attracted much attention on DSSCs. To enhance efficiency, the electrochemical deposition of PEDOT onto FTO glass was carried out in 4 solution deposition ratios 4:6, 6:4, 8:2 and 9:1 of distilled water and acetonitrile. The best efficiency of the resulting DSSCs with 9:1/ PEDOT as compared to the reference cell. The excellent photoelectric properties, and low cost allow the PEDOT electrode to be a credible alternative electrode for use in DSSCs.

Fluorescent material concentration dependency: Förster resonance energy transfer in quasi-solid state DSSCs

Förster resonance energy transfer (FRET) is critical for wide spectral absorption, an increased dye loading, and photocurrent generation of dye-sensitized solar cells (DSSCs). This process consists of organic fluorescent materials (as an energy donor), and an organic dye (as an energy acceptor on TiO2 surfaces) with quasi-solid electrolyte. The judicious choice of the energy donor and acceptor facilitates a strong spectral overlap between the emission and absorption regions of the fluorescent materials and dye. This FRET process enhances the light-harvesting characteristics of quasi-solid state DSSCs. In this study, DSSCs containing different concentrations (0, 1, and 1.5 wt%) of a fluorescent material (FM) as the energy donor are investigated using FRET. The power conversion efficiency of DSSCs containing FMs in a quasi-solid electrolyte increased by 33% over a pristine cell. The optimized cell fabricated with the quasi-solid state DSSC containing 1.0 wt% FM shows a maximum efficiency of 3.38%, with a short-circuit current density (JSC) of 4.32 mA/cm−2, and an open-circuit voltage (VOC) of 0.68 V under illumination of simulated solar light (AM 1.5G, 100 mW/cm−2).

Influence of an Al-blended TiO2 photoanode on the photovoltaic properties of n-DSSCs

ABSTRACT The performance of n-type dye-sensitized solar cells (n-DSSCs) based on a Co complex redox electrolyte were investigated with a photoanode composed with mixer consists of both TiO2 and AlCl3. The surface of TiO2 films coated on FTO glass substrates was amended by soaking them in a TiCl4:AlCl3 blended aqueous solution at different molar ratios, and calcining them to yield the surface-modified photoelectrodes (Ti:Al/TiO2). An enhancement in the power conversion efficiency 2.02% of the resulting n-DSSCs with Ti:Al (9:1)/TiO2 compared to the reference cell by the plain TiO2. The dark current measurements, incident photon-to-current conversion, and efficiency electrochemical impedance spectroscopy (EIS) revealed that the combination of a mixer onto the TiO2 film led to the delay of the charge recombination among the photo-injected electrons and Co complex redox electrolyte, resulting in an enhanced short-circuit current and open-circuit current, compared to device without surface modification.