Engineers at the Massachusetts Institute of Technology (MIT) have proposed a new way of harnessing photons for electricity with the potential for capturing a wide spectrum of solar energy.

A visualization of the broad-spectrum solar energy funnel. Credit: Yan Liang

The "solar energy funnel" takes advantage of materials under elastic strain to produce unprecedented properties. According to MIT, in this case, the "funnel" is a metaphor: Electrons and their counterparts, holes -- which are split off from atoms by the energy of photons -- are driven to the center of the structure by electronic forces, not by gravity as in a household funnel.

The pressure imparts elastic strain. The varying strain changes the atomic structure just enough to "tune" different sections to different wavelengths of light -- not just visible light, but also some of the invisible spectrum, which accounts for much of sunlight's energy.

Strain is the pushing or pulling of a material into a different shape and can be either elastic or inelastic. In the solar funnel, the electronic characteristics of the material lead them to the collection site, which should be more efficient for charge collection.

MIT engineers believe the manipulation of strain in materials opens a whole new field of research.

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