14 DAY TRIAL // What is the first thing that comes to your mind when you hear: solar-energy powered cars? Let me guess... big ugly solar panels, right? That's about to change real quick, so say a couple of researchers from the United Kingdom. Instead of using solid heavy large silicon solar panels, scientists propose the use of printable flexible solar cells, or even better - paint capable of harnessing the power of the Sun to convert it into electric energy. This way, the solar cells can be simply painted on the sheets of metal covering the car, the walls or even the roofs of a house.
The painting process is simple and rapid, and it can be accomplished with the help of a simple painting roller. By doing so, Swansea University scientists created a solar cell at a rate of 40 square meters per minute. The new photovoltaic paint has the same capabilities as the silicon solar panel, and is based on dye-sensitised molecules of titanium dioxide pigment.
The pigment catalyzes the release of electrons from the substrate towards the electrolyte layer which collects them, thus delivering power into an electronic circuit before returning to the titanium dioxide pigment. Although the fabrication method involving the painting of dye molecules is much easier and less expensive than the complex manufacturing process followed in the case of silicon solar cells, the photovoltaic paint has proven to be less efficient at converting light into electric energy.
The original idea used by the Swansea team is supposed to have arisen from a previous experiment involving the study of steel elements while degrading under the action of different chemical substances. It is well known that titanium dioxide is light sensitive, as its color is being altered by its action. Maarten Wijdekop thought that they could use this property by creating a photo-sensitive paint that can act as a solar cell.
The research team reports that it has already been contacted by the steel manufacturer Corus, in the hope to obtain a special paint that can protect steel structures more efficiently. Printable solar cells and solar cells in general are usually being fashioned into layers, each with a unique functional role. In order to create a paint solar cell, one would first have to apply a base of normal paint directly onto the steel structure, after which the electrolyte and dye paints may follow in the respective order. Last but not least - clear protective paint layers to protect the previous layers from the fearsome action of the elements.
In a demonstration of the technology, the Swansea research team constructed an experimental solar cell in the hope that future improvements would enhance the energy conversion rates. The first of the possible improvements would be the development of new sets of paints for the different layers used to construct it.
Nonetheless, optimizing the entire process could take an incredible long time. Mark Ratner of Northwestern University in Chicago warns that during tests of solar cells outside Japan, research teams could not improve the efficiency not even after 4 years of continuous experiments. He has already identified one possible flaw in the design, in that the titanium dioxide photosensitive dye may experience some problems with boosted electrons being forced back into the dye, instead of being pumped into the electrolyte layer.