Breakthrough promises significantly more efficient solar cells

A new technique developed by U of T Engineering Professor Ted Sargent and his research group could lead to significantly more efficient solar cells, according to a recent paper published in the journal Nano Letters.

The paper, "Jointly-tuned plasmonic-excitonic photovoltaics using nanoshells," describes a new technique to improve efficiency in colloidal quantum dot photovoltaics, a technology which already promises inexpensive, more efficient solar cell technology. Quantum dot photovoltaics offers the potential for low-cost, large-area solar power – however these devices are not yet highly efficient in the infrared portion of the sun's spectrum, which is responsible for half of the sun's power that reaches the Earth.

The solution? Spectrally tuned, solution-processed plasmonic nanoparticles. These particles, the researchers say, provide unprecedented control over light's propagation and absorption.

The new technique developed by Sargent's group shows a possible 35 per cent increase in the technology's efficiency in the near-infrared spectral region, says co-author Dr. Susanna Thon. Overall, this could translate to an 11 per cent solar power conversion efficiency increase, she says, making quantum dot photovoltaics even more attractive as an alternative to current solar cell technologies.