International Journal of Energy Research, Vol.44, No.13, 10846-10859, 2020
Effect of using betalain, anthocyanin and chlorophyll dyes together as a sensitizer on enhancing the efficiency of dye-sensitized solar cell
The paper explored the mechanism of working of dye sensitizers for the improvement of efficiency of environmentally benign dye-sensitized solar cells (DSSC). The identified natural dyes namely anthocyanin (A), betalain (B) and chlorophyll (C) were extracted from Roselle (Hibiscus sabdariffaL.), spinach (Spinacia oleracea) and beetroot (Beta vulgaris) respectively. Light absorption performance of dyes was recorded by ultraviolet-visible (UV-vis) spectroscopic analysis followed by direct and indirect band gap calculation. The effect of functional groups present in the dyes studied by Fourier transform infrared spectroscopy (FTIR) and binding of the dyes on TiO(2)through surface morphology of sheets was identified employing field emission scanning electron microscopy (FESEM). Photovoltage characteristics (I-V) and induced photon to current efficiency (IPCE) measurements were also noted followed by the stability studies. The N3 (synthetic dye chosen for the reference) dye-based cell showed the highest efficiency of 6.19% out of all of 11 cells fabricated using different sensitizers. The DSSC fabricated using the novel mixed dye (ABC) mixture gave the highest efficiency of 3.73%, however it showed similar drop (almost 22%) in efficiency as that with of N3 dye in stability studies. The mechanism for the increase in the overall power conversion efficiency of DSSC was also suggested.