One of the major challenges in developing solar panels has been creating photovoltaic cells which can absorb as much solar energy as possible – without overheating to the point that they begin to simply radiate energy back into the atmosphere. In the past, this has meant that commercially available solar cells only manage to convert about 30 percent of sunlight they absorb into energy. Researchers from Purdue University may have found a way to overcome this issue by modifying regular silicon wafers to more efficiently absorb the energy at higher temperatures than ever before.
The new study, published in the journal Applied Physics Letters, outlines how silicon wafers can be coated with thin films of tantalum and silicon nitride to enhance their ability to absorb sunlight. The modified surface is then able to selectively absorb photons within a certain range on the light spectrum, while reflecting those that cannot be used.
The resulting solar cells can withstand temperatures up to 535 degrees Celsius without any performance or stability issues, converting a staggering 50 percent of sunlight into useable energy. This research has some interesting applications – for instance, the same film could be painted on the surface of mirrored parabolic troughs used in concentrated solar plants in order to make them even more efficient.
While the film isn’t yet ready for any kind of commercial application, the authors of the study hope it will inspire others to try a similar experimental approach to enhancing solar absorption.