Printable Electrolytes Based on Cobalt Complex REDOX Couples for Dye-Sensitized Solar Cells Under Ambient-Light Conditions
Photovoltaics for indoor power generation have recently drawn a lot of attention due to the continuous growing in the use of wearable and portable electronics.In this study, printable electrolytescontaining Co(bpy)2+/3+redox couples and 3-methoxypropionitrile solvents are prepared, and the performance of the corresponding quasi-solid-state DSSCs underambientlightingis investigated. In order to meet the requirement for the printing process, four kinds of polymer systems, i.e., poly(ethylene oxide)(PEO), PEO/poly(vinylidene fluoride-co-hexafluoropropylene),PEO/poly(vinylidene fluoride)and PEO/poly(methyl methacrylate),are employed as the viscous agentsto regulate the viscosity of the electrolyte. Experimental results show thatamong these polymer systems, the electrolyte using only the PEO polymeras the viscous agent can lead to the highest open-circuit voltage and conversion efficiency for the DSSC, which is ascribed to the biggest charge recombination resistance at the photoelectrode/electrolyte interface. When 9 wt.% PEOis introduced, the obtained electrolyte possesses a viscosity of24.3 Pasec at the shear rate of 0.50 sec1; furthermore, the relevant DSSC displays an outstanding conversion efficiency of21.1%under 200-lux fluorescentlighting. With the use of high-transparency counter electrodes, quasi-solid-state DSSCs featuring bifacial applications are also assembled in this study; such solar cell demonstrates efficienciesof 14.7% and 17.7% under the rear-side and front-side illumination,respectively, illustrating its good capability to be utilized in the indoor environments.
Keywords - Dye-sensitized solar cell,Quasi-solid state, Printable electrolyte, Cobalt, Indoor