Nanoengineering TiO₂ for evaluating performance in dye sensitized solar cells with natural dyes

The current study employs nanoengineering diatom and TiO₂ NPs to form diatom-Si-TiO₂ nanoengineered structures to fabricate a dye sensitized solar cell (DSSC) (DsTnas-DSSC). This was characterized and spin coated on a Fluorine-doped Tin Oxide (FTO) anode plate. The counter cathode was prepared by spin coating graphene oxide on a FTO glass plate and using Lugol's iodine as an electrolyte. The power density of DsTnas-DSSC was estimated with different natural dyes in comparison to conventional photosensitive ruthenium dye. It was found that the natural dyes extracted from plants and microalgae show significant power efficiencies in DSSC. The percentage efficiency of maximum power densities (PD_max) of DsTnas-DSSC obtained with photosensitive dyes were 9.4% with synthetic ruthenium dye (control) and 7.19% > 4.08% > 0.72% > 0.58% > 0.061% from natural dyes found in Haematococcus pluvialis (astaxanthin) > Syzygium cumini (anthocyanin) > Rosa indica (anthocyanin) > Hibiscus rosa-sinensis (anthocyanin) > Beta vulgaris (betalains), respectively. Among all the natural dyes used, the PD_max for the control ruthenium dye was 6.164 mW m^-2 followed by the highest in astaxanthin natural dye from Haematococcus pluvialis (5.872 mW m^-2). Overall, the use of natural dye DsTnas-DSSC makes the fuel cell low cost and an alternative to conventional expensive, metal and synthetic dyes.