Aqueous soft matter based photovoltaic devices

We present a new type of photovoltaic systems based on aqueous soft gel materials. Two photosensitive ions, DAS(-) and [Ru(bpy)(3)](2+), were used as photoactive molecules embedded in aqueous gel. The hydrogel photovoltaic devices (HGPVs) showed performance comparable with or higher than those of other biomimetic or ionic photovoltaic systems reported recently. We suggest a provisional mechanism, which is based on a synergetic effect of the two dye molecules in photocurrent generation. We found an efficient replacement of the expensive Pt counter-electrode with copper coated with carbon materials, such as carbon nanotubes, carbon black or graphite. These Cu electrodes coated with carbon layers could drastically reduce the cost of such hydrogel devices without efficiency loss. Thus, a new class of low cost and flexible photovoltaic cells made of biocompatible matrix was demonstrated. Biologically derived photoactive molecules, such as Chlorophyll and Photosystem II, were successfully operated in aqueous gel media of such HGPVs.