Experimental and theoretical study of the dye-sensitized solar cells using Hibiscus sabdariffa plant pigment coupled with polyaniline/graphite counter electrode

Abstract In this research work, the extraction, characterization, device fabrication, and theoretical investigation of Hibiscus sabdariffa plant extract, for possible application in solid DSSCs, are reported. The plant extract was analyzed using FT-IR and UV–Vis spectrophotometry. Polyaniline on graphene was used as the counter electrode whereas titanium (IV) oxide was used as the photo anode for the fabricated DSSCs. The experimental results obtained for the open circuit voltage, short circuit current density, field factor, maximum power and conversion efficiency are 0.925 V, 0.073 A/cm 2 , 1.43, 1.04 W, and 0.044 % respectively. The excited states of anthocyanin (delphinidin) and quercetin, the most stable structures of Hibiscus sabdariffa plant extract, were studied using density functional theory method. In addition, the theoretical open circuit voltage, light harvesting efficiency, coupling constant, free energy change, and HOMO–LUMO energy gap were predicted for the photovoltaic properties. The theoretical results suggest that quercetin has relatively better photovoltaic properties and, hence, potentially a better dye for solar cell application.