Black Silicon Harnesses Infrared Light

Posted on Oct 15, 2012 in Energy Efficiency by Contributing Writer 0 Comments

Most of today`s solar panels are based on photovoltaic cells made out of silicon or other materials that converts sunlight into electricity. None of these have been capable of harnessing the energy from light that is outside the visible spectrum.

Scientists at the Fraunhofer Institute have been working on this problem for quite some time. They have found that by using black silicon, they can make solar cells that are capable of almost the entire spectrum of sunlight, including infrared radiation.

Black Silicon Captures Unseen Energy

It is thought that by combining conventional solar cells with black silicon provides the cells with the capability to harness energy from different wavelengths. Thereby, a more efficient solar cell can be made – whether it is more cost-efficient is an entirely different case. The same researches at the Fraunhofer Institute have now reported that they have found away to double the efficiency rates of these black silicon cells. This feat was achieved by irridiating standard silicon with “with femtosecond laser pulses under a sulfur containing atmosphere” using the words of the scientists themselves. In laymen terms that means that black silicon has been made by integrating sulfur into traditional silicon.

There is not enough energy in infrared light to “bounce loose” the electrons in traditional silicon, which stops the particles from generating electrical power. When sulfur is incorporated in black silicon the electrons “sit looser”.

“We used the laser pulses to alter the embedded sulfur in order to maximize the number of electrons that can climb up while minimizing the number that can go back down,” said Dr. Stefan Kontermann, one of the researchers, referring to the energy levels that have to “climbed over” in order to free electrons.

The laser system that the new technology is based on is currently early in the development phase, but the researches at Fraunhofer Institute are confident they will be able to advance to the mass production stage soon.

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Article by Environmental Engineer Mathias. He writes more about new solar power technologies, including their expected costs at his blog Energy Informative