Thin-film solar cells have a host of potential applications. Because they're thin, lightweight and flexible, the cells could be placed on a variety of surfaces and be incorporated into structures or even fabrics. Researchers have spent a lot of time working on increasing their efficiency, which lags behind their rigid silicon counterparts, but is consistently getting closer and closer. The major problem though is that the materials that most thin-film cells are made of are becoming increasingly scarce because of the growing demand.
CIGS cells, which stands for copper, indium, gallium and selenium, are the most common thin-film solar cell, but three of those metals are what's known as hitchhiker metals, or those that are only available as a byproduct of the mining of another material. These hitchhiker metals, as we've reported before, are becoming harder to come by as demand rises because there's no way to scale up production of something that exists only as a byproduct. Other than recycling of the metals in already existing electronics and solar panels, the best plan is to make create technologies using more abundant materials.
Enter IBM. The tech giant along with its partners Tokyo Ohka Kogyo, DelSolar and Solar Frontier, have developed a thin-film solar cell using the readily available materials copper, zinc, and tin that has hit a world-record efficiency for solar cells of its kind. The CZTS cell was able to achieve a conversion efficiency of 11.1 percent, a ten percent gain over the previous record.
Phys.org reports, "The IBM research team is hoping to make CZTS even more efficient, perhaps reaching fifteen percent, which would of course make it a viable alternative to CIGS, though they don’t expect to reach that goal for at least another couple of years. If the team succeeds then it’s possible production of electricity using thin film solar cells could jump dramatically, up to 500 gigawatts, the team predicts."
Because the CZTS cell is made with abundant materials, production could easily be scaled up, unlike with cells using rare materials. Also, these more common metals are cheaper, meaning the cells would come at a lower cost too. The IBM team notes that these cells are well-suited for mass production because they can be made using a simple additive production technique as opposed to the more expensive etching technique required to make silicon solar cells. They hope all these advantages will lead to solar cells that are more widely adopted and more of the world's electricity coming from solar power.