Fig. 6 shows an action spectrum of IPCE for the DSSC sensitized with Siahkooti dye extract. As shown, when the wavelength of incident light is in the range of 400–650 nm, the extracted dye has
higher photon to electron conversion efficiency from the energy of incident light compared with the other reported natural dye based DSSCs. In addition, when the wavelength of incident light
is located at 400 nm, IPCEmax of the Siahkooti dye based DSSC shows the acceptable value of 35%.