New Solar Cell Targets the 40% of Sun’s Energy That Others Miss

A solar farm at Nellis Air Force Base, Nevada
A solar farm at Nellis Air Force Base, Nevada U.S. Air Force , Airman 1st Class Nadine Y. Barclay

A group of researchers lead by Michael Strano announced today that they have developed a prototype solar cell that can draw on a broader range of solar energy, and hence provide more electricity, than traditional technology.

MIT News says,

The new cell is made of two exotic forms of carbon: carbon nanotubes and C60, otherwise known as buckyballs… The carbon-based cell is most effective at capturing sunlight in the near-infrared region. Because the material is transparent to visible light, such cells could be overlaid on conventional solar cells, creating a tandem device that could harness most of the energy of sunlight.

These new carbon solar cells are not the first attempt at capturing infrared (IR) solar radiation. Recent research has lead to a few different promising paths to infrared solar cells, including: dyes designed to modify conventional photovoltaic cells, IR-sensitive nanoscale antennas, a spray-on light-sensitive plastic material, and a technique to break the conversion of radiation into flowing electrons into multiple, more easily achieved steps.

The new all-carbon solar cells are related to, but distinct from, the field of thermal photovoltaics—cells designed to capture heat from everyday objects. Thermal photovoltaics draw on much lower-energy radiation than would the new carbon-based cells which use light from the near-infrared part of the electromagnetic spectrum, that is, the part of the infrared spectrum closest to visible light.

Though promising, the technology still needs a ton of work. MIT says,

The carbon cells will need refining, Strano and his colleagues say: So far, the early proof-of-concept devices have an energy-conversion efficiency of only about 0.1 percent.

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