Under Construction!

And It's Pretty Efficient Too!
IBM researchers has recently published a paper in the journal Advanced Materials about a very promising breakthrough in solar technology. What makes it a breakthrough compared to existing solar technologies (such as silicon-based solar cells, or CIGS thin film)? The fact that it's made from earth abundant materials that can be found in large quantities relatively inexpensively (not quite dirt cheap, but cheaper than what we have now).
Magnified view of a cross section of the compound Cu2ZnSn(S,Se)4 Image: IBM