Photosynthesis in plants

Plant leaves are tiny factories in which sunlight absorbed by chlorophyll converts carbon dioxide gas and water into carbohydrates (glucose) and oxygen, thus providing for the energy requirements of the plant.

Artificial Photosynthesis

Artificial photosynthesis is based on the concept of a dye analogous to chlorophyll absorbing light and thus generating electrons which enter the conduction band of a high surface area semiconductor film and further move through an external circuit, thus converting light into "green" power.

This is a two-step photovoltaic process, unlike the one step process of conventional PV.

Dyesol's technology is different to any classical PV

• It is a photoelectrochemical cell: charge separation occurs on interface between a wide bandgap semiconductor (e.g. titanium dioxide) and an electrolyte.
• It is a nanoparticulate porous film: it is not a dense film as is amorphous silicon, but a nanoparticulate cell: a "light sponge"
• It is a Dye-sensitised cell: a dye monolayer chemically absorbed on the semiconductor is the primary absorber of sunlight; free charge carriers are generated by electron injections from a dye molecule, excited by visible radiation.

The basic DSC structure.

In basic realization a Dye Solar Cell comprises a layer of nano-particulate titania (Titanium Dioxide) formed on a transparent electrically conducting substrate and photosensitized by a monolayer of dye. An electrolyte, based on an Iodide - Tri-iodide redox system is placed between the layer of photosensitized titania and a second electrically conducting catalytic substrate.