A couple of years ago, when I first started writing for The Green Optimistic, news about solar cells were flooding the blogs and feeds. I remember that no day passed by without a team from somewhere reporting on new and improved silicon-based cells. It was also the time of the raise of perovskite material. Scientists were looking into options and possibilities to incorporate these into solar cells, mainly because the material allows for cheaper, flexible and light-weight solar devices.
Unfortunately, no one came up with a break-through solution that would make these worth incorporating in devices, and the topic somewhat died out. Of course, I do not mean that the research and interest in the field have disappeared, not at all. However, the information shared with the public, which used to get everyone excited, somehow stopped coming.
A team of great scientists from Georgia Institute of Technology, University of California San Diego and Massachusetts Institute of Technology, finally broke the silence, and they did it with a bang. Their study published in of the most prestigious scientific journals- Science, reports on a new method for improving the performance of perovskite-based solar cells.
Before I get onto the details, here is a bit of a background, so you can get an idea of the status quo. Perovskite-based solar cells are very attractive. They are quite cheap to produce. Their flexibility allows for a wide range of cool devices or installation methods. And last but not least, their efficiency is getting closer and closer to silicon-based cells, thanks to continuous research. The problem, however, is that the life time of perovskite-based solar cells is only a couple of months. Solving this challenge, has caused numerous researchers many sleepless nights with not much progress.
Fast-forwarding to February 8th of this year, and we find ourselves on the verge of a game-changing revelation. The team of scientists, whom I mentioned earlier, discovered that adding alkali metals, such as cesium and rubidium, to a mixed bromine and iodine lead perovskite, improves the performance and stability of the solar cells. The reason why this special chemical cocktail works, is because when adding cesium and rubidium, bromine and iodine mix together better. This improves the conversion efficiency, and makes the solar cells operate at their best.
In addition, the team discovered that inactive “dead zones”, which occur due to clustering of halide metals, are not a problem here. In other solar cells, this causes reduction in performance. The scientists concluded that this shows great robustness of perovskite-based cells, and opens up possibilities for further developments and improvements.
Will this be the breakthrough that will finally make solar cells super cheap, thin and flexible? What do you think?
Image (c) Rob Felt, Georgia Tech