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We synthesized POBA dye and studied its performance as a sensitizer and co-sensitizer. In addition, we present a simple method for producing Ni-doped TiO2 with various molar concentrations for use as a photoanode in a DSSC. Further, poly(vinylidene fluoride)/polyethylene glycol (PVDF-PEG) gel polymer electrolytes (GPEs) having different concentrations of 1-n-hexyl-3-methylimidazolium iodide were prepared and optimized for usage in DSSCs. We initially tested the performance of POBA dye on TiO2 and Ni-doped TiO2 photoanode materials. Among the POBA sensitized devices, 4% Ni–TiO2 showed a high efficiency of 1.85%. Then, we sensitized Z907 dye on the 4% Ni–TiO2 photoanode, followed by sensitizing it with POBA, which compensated the absorption defect of the Z907 dye as well as filling the gap between the standard dye molecules. This approach enhances and broadens the absorption spectrum of the dyes by molecular filling, compensates for the lack of absorption of Z907, and reduces the recombination of charges. The Z907-based DSSC showed 4.52% efficiency, and after co-sensitization, the DSSC showed an increase in efficiency (5.77%). These findings show that co-sensitizers can cover the naked spectrum in the ultraviolet-visible region, fill the empty space on Ni–TiO2, and reduce recombination reactions. The main motive of this research is to enhance the photo-ability of sensitizers and metal-free co-sensitizers in a Ni–TiO2 photoanode and blend gel polymer electrolyte-based DSSCs. [ABSTRACT FROM AUTHOR]

The existing energy situation demands not only the huge energy in a short time but also clean energy. In this regard, an integrated photo-supercapacitor device has been fabricated in which photoelectric conversion and energy storage are achieved simultaneously. A novel carbazole-based dye is synthesized and characterized for photosensitizer. The silver-doped titanium dioxide (Ag-TiO2) is synthesized, and it is used as photoanode material. Different concentrations of tetrabutylammonium iodide (TBAI)-doped polyvinyl alcohol–polyvinylpyrrolidone (PVA-PVP) blend polymer electrolytes are prepared, and their conductivity and dielectric properties were studied. Reduced graphene oxide (r-GO) is synthesized by a one-pot synthesis method and confirmed using Raman spectroscopy for counter electrode material in dye-sensitized solar cell (DSSC) and supercapacitor electrodes. The DSSC having 4% Ag-TiO2–based photoanode showed the highest efficiency of 1.06% (among r-GO counter electrodes) and 2.37% (among platinum counter electrodes). The supercapacitor before integration and after integration exhibits specific capacitance of 1.72 Fg−1 and 1.327 Fg−1, respectively. [ABSTRACT FROM AUTHOR]

The current era focuses not only on producing solar energy but also preserving it for future use. Dye-sensitized solar cells (DSSC) and supercapacitors (SC) are such energy-based devices. DSSCs capture the solar energy and SCs store this captured energy. A natural anthocyanin dye extracted from Garcinia indica (kokum fruit) was used in the DSSCs. SnO2, one of the promising electrode materials for DSSC, was synthesized via a microwave technique. Blend polymer electrolytes (BPE) were prepared through a solution casting technique. A polyvinyl pyrrolidone (PVP) and polyvinyl alcohol (PVA) blend with varying concentrations of potassium iodide, along with iodine dopant, was prepared as a BPE electrolyte composition. The best of the PVA-PVP/KI composition was chosen using Nyquist plots of electrochemical impedance spectroscopy (EIS). Varying the temperature, the dielectric and conductivity study of the chosen composition was studied in detail. A fast/single-step synthesis technique, namely a laser-engraved approach, was used for few-layer graphene synthesis. This graphene serves as a common platform for the DSSC-SC integrated device: as a counter electrode in DSSC and graphene-graphene symmetric electrode in SC. A DSSC-SC integrated device was fabricated and characterized using various analytical and microscopy techniques. The integrated device showed a 0.42 fill factor and 0.56% efficiency. The discharge time for integrated DSSC-SC cells was found to be increased threefold. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new finding of tubular array of 10–20μm in length and 1–2μm in thickness of gel polymer electrolyte (GPE) having 2.2×10−3 Scm−1 conductivity is reported. [•] Thermal and electrochemical characterizations of GPEs show good interaction among the polymer, plasticizer and salt. [•] GPE based supercapacitor demonstrates high capacitance of 186Fg−1. [•] Low temperature studies did not influence much on capacitance values obtained from AC impedance studies. [•] Charge–discharge exhibits high capacity with excellent cyclic stability and energy density. [ABSTRACT FROM AUTHOR]

Proton and lithium-ion conducting biodegradable solid polymer electrolytes were prepared using blends of poly(styrene sulphonic acid) (PSSA) and starch for supercapacitor applications. The ionic conductivities have been calculated using the bulk impedance obtained through impedance spectroscopy with varying blend ratio and plasticizer. Glycerol as plasticizer improved the film formation property, while lithium perchlorate (LiClO) as dopant enhanced the conductivity. The maximum conductivity has been found to be 5.7 × 10 Scm at room temperature for 80/20 (PSSA/starch) blend ratio. The dielectric studies showed relaxation peaks indicating proton and Li conduction in the plasticized polymer blend matrix and dielectric modulus also exhibited a long tail feature indicating good capacitance. Differential scanning calorimetry thermograms showed two peaks and decreased with varying blend ratio and plasticizer. A carbon-carbon supercapacitor was fabricated using suitable electrolyte, and its electrochemical characteristics using cyclic voltammetry, AC impedance and galvanostatic charge-discharge were studied. Supercapacitor showed a fairly good specific capacitance of 115 Fg at 10 mV s. [ABSTRACT FROM AUTHOR]

Abstract: Biodegradable polymer electrolyte comprising the blend of chitosan (CS) and starch, plasticized with glycerol, as host polymer and lithium perchlorate (LiClO4) as a dopant is prepared by solution casting technique. The variation of conductivity has been investigated as a function of polymer blend ratio, plasticizer content, and LiClO4 concentration at temperature range of 298–343K using electrochemical impedance spectroscopy. The maximum conductivity is found to be 3.7×10−4 Scm−1 at room temperature for 60:40 (CS/starch) concentration. The dielectric properties of the electrolyte film exhibit a long tail feature indicating good capacitance. The activation energy of all samples is evaluated using the Arrhenius plot and it is found to be 0.52–0.75eV. The DSC thermogram peaks for CS-starch blends decreases with increase in the LiClO4 content. A carbon–carbon supercapacitor is fabricated using suitable blend electrolyte ratio and its electrochemical characteristics are discussed at various temperatures and current density. This supercapacitor shows a fairly good specific capacitance of 133Fg−1. [Copyright &y& Elsevier]

• Screen printing of a 2D graphite/Cu supercapacitor with PVA-PVP polymer electrolyte. • A novel method introduced to deposit the electrolyte on the current collectors using a porous wet paper. • Overcame several disadvantages of conventional solid-state gel electrolytes. • Cyclic Voltammetry at various scan rates showed a specific capacitance of 24.12 F g−1. • Excellent flexibility with a maximum relative resistance change of 4.83% at a bending angle of 180°. A 2D supercapacitor with graphite/copper nanoparticle electrodes and a PVA-PVP polymer electrolyte was screen printed. A novel method to deposit the electrolyte on the current collectors using a porous wet paper has been described to overcome several disadvantages of conventional solid-state gel electrolytes. SEM imaging showed the ideal size of deep pores in the paper-based medium which assisted the electrolyte in storing charge and facilitated high conductivity and capacitance. Electrochemical analysis via Cyclic Voltammetry at various scan rates showed a specific capacitance of 24.12 F g−1. Cyclic stability and charge-discharge times were studied via galvanostatic charge-discharge cycles. The excellent flexibility of the device has been demonstrated by plotting the absolute and relative resistance change across the Cu electrodes at different bending angles with the maximum relative resistance change shown to be less than 5%. [ABSTRACT FROM AUTHOR]