Dye-sensitized Solar Cells

Dye-sensitized solar cells are the most promising of the third and latest generation of solar cells. Under development for the last 20 years, this technology is ready for large scale commercialization to provide affordable solar energy to the masses.

Artificial Photosynthesis

Dye-sensitized solar cells work on the principles of photosynthesis, the naturally occurring process in plants which sustains life on Earth. Unlike silicon solar cells, these cells obtain energy from sunlight using dyes which are abundant, cheap and environmentally unobtrusive.

The bottom-line

Dye-sensitized solar cells bring to the fore advantages over previous generations of solar cells:

  • Complete to semi-transparency and colour flexibility for aesthetic and seamless integration into a variety of surfaces.
  • Lightweight and flexible for greater possibilities and novel applications. Lower cost of distribution, handling and installation which can be passed on to consumers.
  • High efficiencies even under low, diffused and indirect light conditions. They can operate under non-ideal working conditions (such as indoors) without compromise in performance.
  • Lower cost and embodied energy to manufacture, leading to shorter payback times.

The intricacies

Dye-sensitized solar cells generally consist of two sandwiched electrodes with an electrolyte solution between them. A porous network of TiO2 nanoparticles is attached to the front surface electrical contact (anode). Organic dye molecules are adsorbed onto the surface of the TiO2 particles. They absorb light and inject electrons into the TiO2 particles. The electrons then diffuse through the TiO2 particle network to the anode. Via an external circuit, they reach the back surface contact (cathode). The electrolyte solution captures the electrons at the cathode and transfers the electrons back to the dye molecules in order to complete the electrical circuit.

dye-sensitized_transparency
 Click on the image for an enlarged view

 Schematic illustration of the various components in a Dye Sensitized Solar Cell.