Yet another 3-D solar cell

A recent solar advancement out of Georgia Institute of Technology may be innovative, but it is by no means novel.

Researchers said they’ve come up with a three-dimensional photovoltaic system that could allow PV systems to be located other places besides rooftops. The technology uses zinc oxide nanostructures grown on optical fibers and coated with dye-sensitized solar cell materials.

The researchers said the technology enables PV generators to be foldable, concealed and mobile. According to Professor Zhong Lin Wang, optical fiber could conduct sunlight into a building’s walls, where the nanostructures would convert it to electricity.

Dye-sensitized solar cells (DSSC) use a photochemical system to generate electricity, much like photosynthesis. But there's a catch. While inexpensive to manufacture and offering flexibility, they have much lower conversion efficiency than silicon-based cells.

Wang and his team said they achieved an efficiency of 3.3 percent, with higher efficiencies expected down the road after some modifications.

DSSC are considered suitable for lower power applications, such as charging mobile electronic devices (see G24 dye-sensitized solar tech out in time for the holidays). But they seem to be a long way from large array potential.

However, Georgia Tech researchers think using nanostructure arrays to increase the surface area available to convert light could help reduce the efficiency disadvantage. They say it could provide new abilities to incorporate PV into buildings, vehicles and military equipment.

Sacramento, Calif.-based Bloo Solar is also working on using nano-structured photovoltaic cells to capture light and boost the overall power output of solar modules (see Painting solar Bloo).

By increasing the amount of light captured using vertical nanostructures it calls "bristles," Bloo plans to enable modules to generate twice as much power as they do over an entire day today, at dramatically lower materials and systems costs.

Bloo is also not the first to be investigating nano applications in solar:

• Researchers at General Electric, Harvard and RPI have been applying the light amplification capability of nanostructures for some time, as has Khosla Ventures-backed Stion, formerly NStructures.
• NewCyte is bringing to market light amplification nanotube technology from Georgia Tech (see 3D solar cells boost efficiency, reduce size).
• Toledo, Ohio-based Innovative Thin Films is using nanotech to help keep conventional modules cleaner (see Cool companies at Cleantech 2007).
• And a University of California, Santa Cruz researcher revealed nanotech innovations that appear to boost the efficiency of solar applications (see Challenging silicon's grip on solar).

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