Abstract:
Dye-sensitized solar cells are the third-generation photovoltaic devices with low
fabrication cost. Light absorption, charge injection, charge transportation and
charge collection are the main process of a dye-sensitized solar cell. In order to
enhance the light absorption process, the photoanode can be modified either by
modifying the photoanode material or using a suitable dye. In a conventional dyesensitized solar cell, Ru-based commercially available dyes are used. They show
better performance in the solar energy conversion process but they are high-cost
materials. In order to reduce the production cost, natural pigments can be used as
sensitizers. The performance of the cell can be further improved by using two or
more dyes as co-sensitizer materials. In this study, dye pigments have been
extracted from water hyacinth, bougainvillea, false daisy, killiseriya, jamun fruit,
pomegranate fruit, teak leaf and neem leaf and characterized. In order to enhance
the photon absorption, possibility of co-sensitization has been studied. The
maximum wavelength corresponding to the optical absorption for each dye and cosensitized dye were identified for solar cell application. To identify the suitable dye
material for TiO2 based dye-sensitized solar cells, TiO2/dye electrodes were
fabricated and characterized. The mixture of jamun dye and bougainvillea dye
(1:1) shows better absorption in the visible region. Similarly, the combinations of
pomegranate dye and jamun dye (1:1) also shows better absorption in the visible
region. These two co-sensitized dyes can be applied to the dye-sensitized solar cell
as co-sensitizers.
