Patrick J. Kiger

Nearly 60 years after researchers first demonstrated a way to convert sunlight into energy, science is still grappling with a critical limitation of the solar photovoltaic cell.

It just isn't that efficient at turning the tremendous power of the sun into electricity.

And even though commercial solar cells today have double to four times the 6 percent efficiency of the one first unveiled in 1954 by Bell Laboratories in New Jersey, that hasn't been sufficient to push fossil fuel from its preeminent place in the world energy mix.

But now, alternative energy researchers think that something really smallnanotechnology, the engineering of structures a fraction of the width of a human haircould give a gigantic boost to solar energy. (Related Quiz: "What You Don't Know About Solar Power")

"Advances in nanotechnology will lead to higher efficiencies and lower costs, and these can and likely will be significant," explains Matt Beard, a senior scientist for the U.S. Department of Energy's National Renewable Energy Laboratory (NREL). "In fact, nanotechnology is already having dramatic effects on the science of solar cells."

Of course, the super-expensive solar arrays used in NASA's space program are far more efficient than those installed on rooftops. (Related: "Beam It Down: A Drive to Launch Space-Based Solar") And in the laboratory, scientists have achieved record-breaking efficiencies of more than 40 percent. But such contests are a testament to the gap between solar potential and the mass market cells of today.

The power output of the sun that reaches the Earth could provide as much as 10,000 times more energy than the combined output of all the commercial power plants on the planet, according to the National Academy of Engineering. The problem is how to harvest that energy. Todays commercial solar cells, usually fashioned from silicon, are still relatively expensive to produce (even though prices have come down), and they generally manage to capture only 10 to 20 percent of the sunlight that strikes them. This contributes to the high cost of solar-generated electricity compared to power generated by conventional fossil-fuel-burning plants. By one comparative measure, the U.S. Energy Information Administration estimated the levelized cost of new solar PV as of 2012 was about 56 percent higher than the cost of generation from a conventional coal plant.

Nanotechnology may provide an answer to the efficiency problem, by tinkering with solar power cells at a fundamental level to boost their ability to convert sunlight into power, and by freeing the industry to use less expensive materials. If so, it would fulfill the predictions of some of nanotechnology's pioneers, like the late Nobel physicist Richard Smalley, who saw potential in nanoscale engineering to address the world's energy problems. (See related: "Nano's Big Future") Scientists caution that theres still a lot of work ahead to overcome technical challenges and make these inventions ready for prime time. For example, more research is needed on the environmental, health, and safety aspects of nano-materials, said the National Academy of Sciences in a 2012 report that looked broadly at nanotechnology, not at solar applications in particular. (Related Pictures: "Seven Ingredients for Better Car Batteries.")

But Luke Henley, a University of Illinois at Chicago chemistry professor who received a 2012 National Science Foundation grant to develop a solar-related nanotechnology project, predicts there will be major advances over the next five to ten years. "Its potentially a game changer," he says. Here are five intriguing recent nanotechnology innovations that could help to boost solar power.

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Sun Plus Nanotechnology: Can Solar Energy Get Bigger by Thinking Small