An organic solar cell plate

23 October 2013 — Researchers have fabricated an organic solar cell with a high level of transparency and efficiency, which they say could have application in windows, creating a new source of energy for buildings.

In the study published in Nature Photonics, researchers were able to create a semi-transparent cell incorporating a photonic crystal and reach a cell performance almost as good as its opaque counterpart.

By adding an extra photonic crystal to the cell, the scientists from the Institute of Photonic Sciences were able to increase the amount of infrared and ultraviolet light absorbed by the cell, reaching a 5.6 per cent efficiency while preserving a transparency almost indistinguishable from glass.

Organic solar cell technology has been around for about 30 years, however it is now starting to attract interest due to low production costs.

While organic cells have not yet reached the efficiency values of silicon based cells, they have proven to be lighter in weight, more flexible, and more sensitive to low light levels and indirect sun light.

A property explored by this study was their potential to be implemented as a semi-transparent device. To turn the cells into transparent ones, the back metal electrode must be thinned down to just a few nanometers. However, this reduces the device’s capacity to collect sunlight.

The researchers said the efficiency and transparency of their novel cells made them an extremely competitive product for Building Integrated Photovoltaic technologies.