Incorporating graphene in anthocyanin-based dye-sensitized solar cells
The use of natural dyes as sensitizer for dye-sensitized solar cells (DSSC) offers significant advantages such as attainability and cheaper production cost. However, its low power conversion efficiency (PCE) impedes its wide utilization. In this study, enhancement in efficiency of anthocyanin-based dye sensitized solar cells through the incorporation of graphene was studied. Graphene is a two-dimensional sheet of sp”2-hyridized carbon known for its extraordinary mechanical, thermal and electrical properties. This remarkable material was incorporated in the TiO_2 photoanode or with anthocyanin dye dispersion. Current-voltage (IV) and electrochemical impedance spectroscopy (EIS) measurements were carried out to characterize the anthocyanin-based DSSC. Addition of graphene ration into TiO_2 as a photoanode composite and/or in anthocyanin extracts (anthocyanin: graphene dispersion) gave the same positive effect, an increase in PCE from 0.185% without graphene to as high as 0.516% with combined graphene doping of the TiO_2 and using an anthocyanin: graphene dye dispersion. Furthermore, a 30% increase in fill factor was obtained for DSSCs in the presence of graphene. EIS data showed a favourable decrease in charge transfer resistance in the TiO_2 layer as graphene is added to the DSSC, with increased magnitude of the short-circuit current (Jsc). This is explained by graphene providing added conducting pathways for the photo-generated electrons.
Enriquez, E., San Esteban, A. (2013). Incorporating graphene in anthocyanin-based dye-sensitized solar cells. 28th Philippine Chemistry Congress, Dumaguete, Philippines, 10-12 April 2013.