Organic solar cells have been around for decades. The idea behind them is that certain organic molecules-typically types of long polymers-could be cheaply printed, leading to very-low-cost solar cells. But such cells have proven inefficient and have had relatively short lifetimes, so they are used only in niche applications.

Heliatek's panels are more efficient than the polymer-based ones, and are expected to last as long as a conventional silicon solar cell. The company uses short molecules called oligomers instead of polymers. Oligomers are inherently more stable, and can be deposited using a vacuum-deposition process that allows for precise control over the thickness and uniformity of the resulting films.

The organic solar panels convert about 8% of the energy in light into electricity whereas conventional solar panels are in the 14 to 15% efficiency range. But, in cloudy weather or hot environments, which make conventional panels less efficient, the organic ones hold their own.