Perovskite crystals â€“ making solar energy more commercially viable
Solar cells â€“ cells that can absorb light energy to be used in other ways â€“ are an important part of energy efficiency. Energy from the sun is free and environmentally friendly, but the current technology has drawbacks.
Standard solar cells today are made from silicon wafers. While the best ones have a good efficiency â€“ 25% â€“ they are expensive. The less expensive ones have much poorer efficiency, as low as 14%.
Perovskite crystals, however, are a new solar technology which can create high-quality crystalline films over tiny areas that can have up to a 21% efficiency. The biggest problem with these crystals is that the heat required to create them can cause crystals to form unevenly, leaving tiny efficiency-eating pinholes in the film. The heat also limits the materials that the films can be made on, as many plastics are damaged by heat.
A new method created by Yuanyuan Zhou, a graduate student at Brown University, uses chemicals instead of heat. Perovskite precursor chemicals are dissolved in a solvent and coated onto the base material. Another solvent is then used to remove the previous solvent, leaving a pure, ultra-smooth perovskite film.
This method can create much thinner high-quality films over larger surfaces than the previous methods. Because these films can be so thin, they are partially transparent so they could be used to make photovoltaic windows; that is, windows that can absorb solar energy for further use. By tweaking the solutions, these films can even be made in different colours.
More research, testing, and work is being done to increase efficiency and improve the commercial viability of this new technology.
Source: EurekaAlert! http://www.eurekalert.org/pub_releases/2015-03/bu-anm031615.php