Shiso leaf pigments for dye-sensitized solid-state solar cell

A dye-sensitized solar cell made by coating pigments in an extract from shiso leaves on a nanocrystalline film of TiO₂ and subsequent deposition of p-CuI is found to have an energy conversion efficiency of ∼1.3%. Both shisonin and chlorophyll contribute to light energy harvesting as seen from the photocurrent action spectrum of the cell. This is the first successful example of synergistic sensitization by dye cocktail extracted from a single natural resource. The usefulness of studies of this nature in understanding the role of multiple pigments in photosynthesis and broadening of the spectral response of dye-sensitized devices is commented, indicating also the pedagogic value of the experiment.