And I say "sun" advisedy.
This seems like an eco-utopia SF novel coming true right before your very eyes. It's also a really cool demonstration of just how fantastically the processes of evolution have created powerful, efficient systems that rival or better anything we'd been able to do so far.
A new generation of solar cells will use photosynthystic (I'm truly sorry if that's the wrong word, I believe it's made up) processes instead of the photovoltaic effect.
I've been waiting years for this. I would like to have a moss-covered roof that powers my air-conditioning and stereo system.
Now there's a completely unrelated thought: How about putting a small electricity-generating water turbine in the downpipe from your roof to your water tank, so that you get free water and generate electricity during every downpour?