Conductivity/Electrochemical Study of Polyvinyl pyrrolidone-Poly(vinyl alcohol)/I3− Thin Film Electrolyte for Integrated Dye-Sensitized Solar Cells and Supercapacitors D. N. Sangeetha, Niveditha Hegde, Vidyashri Poojari, Dheeraj Devadiga, Y. N. Sudhakar, M. S. Santosh, M. Selvakumar Journal of Electronic Materials, 2020 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. Graphical Abstract
Conductivity and Electrochemical Behavior of Plasticized Polymer Electrolyte for Dye-Sensitized Solar Cell Integrated Supercapacitor Vidyashri Poojari, Dheeraj Devadiga, Niveditha Hegde, D. N. Sangeetha, M. S. Santosh, M. Selvakumar Journal of Electrochemical Energy Conversion and Storage, 2020 The current energy situation requires not only enormous energy in a brief period of time but clean energy as well. In this direction, a dye-sensitized solar cell (DSSC)—supercapacitor (SC) integrated energy device has been fabricated. This embedded energy system has a specific advantage such as easy manufacturing, low manufacturing costs, and flexible substrates compatibility. A natural photosensitizer was extracted from readily available beetroots and characterized using ultraviolet (UV)-visible spectroscopy. The zinc oxide semiconductor was synthesized using microwave technique and regarded as the DSSC photoanode material. The ZnO’s phase, purity, and morphology were investigated using X-ray diffraction (XRD) spectroscopy and scanning electron microscope. The iodine-doped cellulose acetate propionate (CAP) biopolymer electrolyte functions as the DSSC and supercapacitor electrolyte. The solid polymer electrolyte conductivity and dielectric studies were performed using electrochemical impedance spectroscopy (EIS). The laser-induced technique was used to synthesize graphene that plays a dual purpose as photocathode in DSSC and supercapacitor electrodes. The embedded energy unit from the DSSC-supercapacitor demonstrates a 6.75% fill factor representing its decent efficiency.
Synthesis and Characterization of Reduced Graphene Oxide- Polyaniline Composite for Supercapacitor Applications Shruthi, K. M. Vighnesha, Sandhya, D. N. Sangeetha, M. Selvakumar Surface Engineering and Applied Electrochemistry, 2018 Graphene oxide (GO) is synthesized from commercially available graphite powder. The prepared GO is converted to reduced graphene oxide (rGO) by chemical reduction using sodium borohydride and sodium hydroxide. The rGO is characterized via X-ray diffraction, Raman spectroscopy and scanning electron microscopy. Conducting polymer–polyaniline, was prepared by oxidative polymerization in an electrolyte- hydrochloric acid and using ammonium persulphate as oxidant. The structure and doping of polyaniline were studied by Fourier-transform infrared spectroscopy and ultra-violet visible spectroscopy. To enhance the conductivity of the rGO, the conducting polymer mixed with rGO and rGO/Conducting polymer composites were prepared. The composite was characterized by cyclic voltammetry, AC impedance spectroscopy. A symmetrical supercapacitor (SC) has been fabricated based on rGO/PANI composites. The prepared composites were shown specific capacitance of 72 F g–1 at 2 mV s–1.
