Organic sensitizer with azine π-conjugated architecture as co-sensitizer and polymer-based electrolyte for efficient dye-sensitized solar cell

The donor-π-acceptor architecture of a novel organic sensitizer (NHC) is synthesized and used in dye-sensitized solar cells (DSSCs). An azine-spacer (=N-N=) is employed to connect the 3-nitrobenzene anchor unit with the carbazole donor in the sensitizer. Photophysical, electrochemical, and photovoltaic performances of the synthesized dye are studied in depth. Further, polymer-based electrolytes were prepared by doping 1-n-hexyl-3-methylimidazolium iodide (HMIm⁺I⁻) to the polyvinylidene fluoride electrolyte solution and studied their conductivity and dielectric properties. DSSC fabricated with NHC dye and HMIm⁺I⁻-20% electrolyte displayed an efficiency of 1.24%. In addition, NHC co-sensitization with bis(isothiocyanato)(2,2′-bipyridyl-4,4′-dicarboxylato)(4,4′-dinonyl-2,2′-bipyridyl)ruthenium(II) (Z907) is investigated. As a result, the co-sensitized device exhibit greater photovoltaic performance, with an efficiency of 4.76% compared to the cell with Z907 (4.17%) alone, owing to higher short-circuit current density in conjunction with higher open-circuit voltages.