Cool that they did it, and it's a nice first step, but I think the "cheap, abundant carbon!" angle of the story is misleading.

Silicon is pretty damn abundant, and they're complaining about how expensive it is -- it's the processing that matters, and right now processing cheap, abundant carbon to make defect-free layers of graphene, or uniform mixtures of carbon nanotubes (free of catalyst particles, of identical chiralities, lengths, diameters and tube number) is very hard and expensive.

Personally, I'm super interested in what Twin Creeks Technologies (http://www.twincreekstechnologies.com/solar/ -- no affiliation) is going to do. Their processing technology is completely out of left field and seems like it has huge potential.