It's about time to give a serious upgrade to the organic solar cells. Most of the solar panels built today all over the world imply a complicated manufacturing process, based on the use of scarce and extremely expensive materials, layered on top of a silicon substrate, and are able to provide a relatively efficient light for the electric energy conversion ratio. Organic solar panels, on the other hand, seem to be a better solution, as they are easy to build, require cheap materials and, last but not least, can be turned into flexible and very thin films.

Don't get too excited though, as Michael Niggemann from the ISE says that the new organic solar cells are not intended to compete with the classical silicon cells. Although easier to built and cheaper, they are not nearly as efficient as silicon solar cells at converting energy. The new organic solar cells have been developed at the Fraunhofer Institute for Solar Energy Systems ISE, and are as thin as the page of a book.

Their flexibility, however, opens the way towards a wider range of applications, such as building solar cells to power mobile devices, MP3 players, or even self-powering sensors and electronic circuits. The biggest problem with the classical silicon solar cells is that they require transparent conductive materials in order to build the front electrode. Indium tin oxide is one of these materials, albeit indium is a very rare element on Earth, thus very expensive.

Fraunhofer experts argue that they can cut the costs of building solar cells by replacing the high-conductive transparent indium-tin-oxide layer with a lower-conductive transparent polymer electrode sitting on top of a metal layer. The galvanic connection between the two is made by multiple small holes in the solar cell.

Niggemann says that the printing technology could be widely used in the solar cell production process in the future, but more advances in the science of materials should be made before coating materials and substrate technologies are developed. The technology of production for the printable organic solar cell has already been patented by Fraunhofer, and will be presented as an alternative for mass production at the nanotechnology fair taking place in Tokyo, between 21 and 23 February.