|Farish Irfal Saaid||Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia|
|Tseung-Yuen Tseng||Department of Electronics Engineering and Institute of Electronics, National Chiao-Tung University, 1001 Ta Hsueh Rd, Hsinchu 300, Taiwan|
|Tan Winie||Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia|
A quasi-solid-state polymer electrolyte is prepared by incorporating poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) in a propylene carbonate (PC) / 1,2-dimethoxyethane (DME) / 1-methyl-3-propylimidazolium iodide (MPII) liquid electrolyte. The amount of PVdF-HFP in the liquid electrolyte is varied from 0.1 to 0.4 g. Incorporation of 0.1 g of PVdF-HFP decreases the conductivity of the DME/PC/MPII liquid electrolyte from 1.3×10-2 to 5.6×10-3 S cm-1. Conductivity decreases gradually with increasing PVdF-HFP. No-flow “jelly-like” electrolyte samples are obtained for PVdF-HFP ? 0.2 g. The decrease in conductivity is the result of the decrease in ion mobility. Ion mobility was calculated by impedance spectroscopy. The PVdF-HFP quasi-solid-state electrolytes were assembled into dye sensitized solar cells (DSSCs). The performance of the DSSCs was measured under illumination of a 100 mW cm-2 Xenon light source. The DSSC without PVdF-HFP polymer shows an efficiency of 4.88% with short-circuit current density, Jsc of 11.24 mA cm-2, fill factor, FF of 70% and open circuit voltage, Voc of 619 mV. The presence of PVdF-HFP deteriorates the performance of DSSCs, but problems such as electrolyte leakage and volatilization are eliminated. The performance of DSSCs was found to be correlated to the conductivity behaviour of the electrolyte.
Conductivity; Dye-sensitized solar cell; Ionic liquid; PVdF-HFP; Quasi-solid- state electrolyte
Dye-sensitized solar cells (DSSCs) with liquid electrolytes possess high efficiencies (Fukui et al., 2006; Mathew et al., 2014). However, they suffer from leakage and electrode corrosion. Problems associated with liquid electrolytes can be eliminated by solid polymer electrolytes (SPE). But, SPE have low conductivity and poor electrolyte-electrode contact. Hence, the performance of DSSCs with SPE is poor compared to DSSC with liquid electrolytes. To overcome the shortcomings of liquid electrolytes and SPE, a quasi-solid-state electrolyte is introduced.
The quasi-solid-state electrolyte is prepared by incorporating a polymer into a liquid electrolyte. The polymer serves as a gelling agent and provides the electrolyte mechanical stability. In this work, poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) was chosen as a gelling agent for the propylene carbonate (PC) / 1,2-dimethoxyethane (DME) / 1-methyl-3- propylimidazolium iodide (MPII) liquid electrolyte. PVdF-HFP has a high dielectric constant of 8.4 and C-F electron-withdrawing group (Sim et al., 2012), thus promoting salt dissociation. PVdF-HFP consists of crystalline VdF and amorphous HFP. The crystalline VdF offers mechanical strength whereas the amorphous HFP entraps the liquid electrolyte (Pu et al., 2006).
The presence of PVdF-HFP in the PC/DME/MPII liquid electrolyte offers the electrolyte mechanical stability but adversely decreases electrolyte conductivity. The crystalline VdF of PVdF-HFP provides mechanical strength to the electrolyte. However, PVdF-HFP increases electrolyte viscosity and hence reduces the mobility of ions. Reduced electrolyte viscosity is evidenced from the viscosity studies. The reduction in ion mobility results in a decrease in conductivity. The DSSC assembled without PVdF-HFP shows higher efficiency than DSSCs assembled with PVdF-HFP. Although PVdF-HFP deteriorates the performance of DSSCs, it overcomes drawbacks such as electrolyte leakage and volatilization. The low conductivity of electrolytes results in low efficiency DSSCs. Thus, the conductivity of the present quasi-solid-state electrolyte needs to be further improved for application in DSSCs.
The authors wish to thank Universiti Teknologi MARA for supporting this work through PERDANA 5/3 BESTARI (040/2018).
|MME-2344-20181003233747.pdf||Second rebuttal letter|
|MME-2344-20181015150009.pdf||fourt rebuttal letter|
Arof, A.K., Amirudin, S., Yusof, S.Z., Noor, I.M., 2014. A Method based on Impedance Spectroscopy to Determine Transport Properties of Polymer Electrolytes. Physical Chemistry Chemical Physics, Volume 16(5), pp. 1856–1867
Careem, M.A., Aziz, M.F., Buraidah, M.H., 2017. Boosting Efficiencies of Gel Polymer Electrolyte Based Dye. Materials Today: Proceedings, Volume 4(4), pp. 5092–5099
Dissanayake, M.A.K.L., Thotawatthage, C.A., Senadeera G.K.R., Bandara, T.M.W.J., Jayasundera, W.J.M.J.S.R., Mellander, B.E., 2012. Efficiency Enhancement by Mixed Cation Effect in Dye-sensitized Solar Cells with PAN Based Gel Polymer Electrolyte. Journal of Photochemistry and Photobiology A: Chemistry, Volume 246, pp. 29–35
Fukui, A., Komiya, R., Yamanaka, R., Islam, A., Han, L., 2006. Effect of a Redox Electrolyte in Mixed Solvents on the Photovoltaic Performance of a Dye-sensitized Solar Cell. Solar Energy Materials and Solar Cells, Volume 90(5), pp. 649–658
Lam, C., Martin, P.J., Jefferis, S.A., 2015. Rheological Properties of PHPA Polymer Support Fluids. Journal of Materials in Civil Engineering, Volume 27(11), pp. 04015021–1–04015021–9
Mathew, S., Yella, A., Gao, P., Humphry-Baker, R., Curchod, B.F., Ashari-Astani, N., Tavernelli, I., Rothlisberger, U., Nazeeruddin, M.K., Grätzel, M., 2014. Dye-sensitized Solar Cells with 13% Efficiency Achieved through the Molecular Engineering of Porphyrin Sensitizers. Nature Chemistry, Volume 6(3), pp. 242–247
Muhammad, F.H., Jamal, S., Winie, T., 2017. Study on Factors Governing the Conductivity Performance of Acylated Chitosan-Nai Electrolyte System. Ionics, Volume 23(11), pp. 3045–3056
Nagaraj, P., Sasidharan, A., David, V., Sambandam, A., 2017. Effect of Cross-linking on the Performances of Starch-based Biopolymer as Gel Electrolyte for Dye-Ssensitized Solar Cell Applications. Polymers, Volume 9, pp. 667–679
Nursama, N.M., Muliani, L., 2012. Investigation of Photoelectrode Materials Influences in Titania-based-Dye-sensitized Solar Cells. International Journal of Technology, Volume 3(2), pp. 129–139
Pu, W., He, X., Wang, L., Jiang, C., Wan, C., 2006. Preparation of PVDF–HFP Microporous Membrane for Li-ion Batteries by Phase Inversion. Journal of Membrane Science, Volume 272(1-2), pp. 11–14
Saaid, F., Rodi, I., Winie, T., 2017. Effect of Temperature on the Transport Property of PVdF-HFP-MPII-PC/DME Gel Polymer Electrolytes. AIP Conference Proceedings, Volume 1877, pp. 020006–1–020006-6
Sim, L.N., Majid, S.R., Arof, A.K., 2012, FTIR studies of PEMA/PVdF-HFP Blend Polymer Electrolyte System Incorporated with Licf3so3 Salt. Vibrational Spectroscopy, Volume 58, pp. 57–66
Sofyan, N., Ridhova, A., Yuwono, A.H., Udhiarto, A., 2017. Fabrication of Solar Cells with TiO2 Nanoparticles Sensitized using Natural Dye Extracted from Mangosteen Pericarps. International Journal of Technology, Volume 8(7), pp. 1229–1238
Winie, T., Azmar, A., Rozana, M.D., 2018. Ionic Liquid Effect for Efficiency Improvement in Poly(methyl acrylate)/Poly(vinyl acetate)-Based Dye-sensitized Solar Cells. High Performance Polymers, Volume 30(8), pp. 937–948
Winie, T., Arof, A.K., 2014. Impedance Spectroscopy: Basic Concepts and Application for Electrical Evaluation of Polymer Electrolytes. In: Chan, C.H., Chia, C.H., Thomas, S. (eds.), Apple Academic Press, Inc. Canada, pp. 335–363
Winie, T., Shahril, N.S.M., 2015. Conductivity Enhancement by Controlled Percolation of Inorganic Salt in Multiphase Hexanoyl Chitosan/Polystyrene Polymer Blends. Frontiers of Materials Science, Volume 9(2), pp. 132–140