IBM researchers have been developing new efficient thin film type solar cells that use abundant materials instead of the scarce materials used in current thin film solar cells. The materials that IBM is seeking to replace are cadmium, iridium, gallium, and selenide, which make up CIGS type cells. The new CZTSS cells that IBM is working on use copper, zinc, tin, sulfur and selenium, all of which readily available. IBM is also claiming 9.6% efficiency so far for these CZTSS cells, and they note that they have just started researching these new CZTSS cells, so they expect the efficiency to go higher. Their manufacturing technique will also help keep the cost low – IBM is using a simple, non-vacuum process called a “slurry-based coating method” that lets them apply the photovoltaic layer with standard painting or spraying methods.
If you want to read the technical paper that IBM published in the journal Advanced Materials, you can download the pdf here