Nanosolar now has their $1 per 1W cells in production. Their first eighteen months of output is already spoken for.

They have made the advances through manufacturing process improvements rather than solar technology itself. Nothing wrong with that. Through microprocessors our cars have become more efficient and safer. Most of the advances in batteries in the last decades have been because of improvements in manufacturing rather than chemical technology. (more)
Cam Riley: South Sea Republic. Freedom, liberty, equity and an Australian Republic.