Bulky and expensive photovoltaic panels are so 2008. What does the future look like? Entire buildings, rooftops and even windows spray-painted with revolutionary nanoparticle inks that channel solar power into a thin, semi-transparent and relatively inexpensive medium. Sound crazy? Not at all, according to one group of chemical engineers.

Spray-on solar cells may sound like a high-end development, but the technology actually stands to be cheaper than traditional solar panels. “The sun provides a nearly unlimited energy resource, but existing solar energy harvesting technologies are prohibitively expensive and cannot compete with fossil fuels,” says chemical engineer Brian Korgel of the University of Texas at Austin whose team is developing the graffiti-capable solar cells.

Most photovoltaics are currently made of silicon, but the inks developed by Korgel’s team are made up of copper indium gallium selenide (or CIGS) — sunlight-absorbing nanoparticles that are 10,000 times thinner than a strand of hair according to the National Renewable Energy Laboratory. These nanocrystals are made into a solution and then spraypainted onto a substrate. If the crystals can do what Korgel says they can do, this new method has the potential to boost the applications of solar power exponentially.

The process is still in the works - thus far, the prototypes that have been developed can only convert 1% of the sunlight that hits the cell into electricity. The goal conversion is 10%, so there is still quite a way to go. “If it works, I think you could see it being used in three to five years,” explains Korgel.

[inhabitat]