doi:10.1038/nindia.2017.47 Published online 13 April 2017
Scientists from Indian Institute of Technology Roorkee have used the purple pigment of Indian summer fruit jamun to make an inexpensive ‘sensitizer’ for Dye Sensitized Solar Cells (DSSCs) or Grätzel cells1. These natural sensitizers hold promise in replacing expensive chemical dyes to make the solar cells.
Lead researcher Soumitra Satapathi and M. Sc student Nipun Sawhney from IIT Roorkee’s physics department used anthocyanins – naturally occurring pigments that give characteristic colour to jamun, plum, black currant and many berries. They extracted anthocyanin from these fruits using acidified ethanol. The carbonyl and hydroxyl groups on the anthocyanin molecule easily bind with titanium dioxide nanoparticles, which are used to make the photoanode – an important component of DSSCs.
Grätzel cells are low cost, easy to fabricate and eco-friendly, therefore attracting considerable research interest. However, conventional sensitizers – mostly ruthenium – used in these DSSCs are expensive and scarce.
“Wide availability of these pigmented fruits with high concentration of anthocyanins makes them potential candidates for low cost energy production,” Satapathi says.
1. Sawhney, N. & Satapathi, S. Utilization of naturally occurring dyes as sensitizers in Dye Sensitized Solar Cells. IEEE J. Photov. 7, 539-544 (2017)