I was watching new inventors last year and a professor and a young scientist came on.
They had a paint they had developed which was pretty much ready to market - it was more efficient than the equivalent size solar panel, it was 1/3 the price, and it was flexible and could be applied to any surface. Its payback period was bout 7 months.
So where the hell did it go?
http://www.dyesol.com/index.php?page...iveitemlimit=2
This is the only company I could find and there's no one selling the stuff.