If you've ever ventured out into the middle of the desert, you've likely encountered a solar field of sorts. On the way to Las Vegas, for example, there exists a solar plant that leverages thousands of glass reflectors to burn hot with the power of the sun. But when it comes to more domesticate uses of the sun, researchers and consumers have been limited by the capabilities of light-absorbing perovskite films used in solar cells. Now, however, thanks to a PhD researcher at Brown University, the tides may have changed.
In a study published this week in the Royal Society of Chemistry's Journal of Materials Chemistry A, Yuanyuan Zhou of Brown University and his advisor Nitin Padture describe a new method of making perovskite films for solar cells that will be especially effective in creating ultra-thin films that are semi-transparent. By using a room-temperature solvent bath to create perovskite crystals, rather than the blast of heat used in current crystallization methods, the new technique produces high-quality films with precise control that is perfect for mass production methods.
"Using other methods, when the thickness gets below 100 nanometers you can hardly make full coverage of film. You can make a film, but you get lots of pinholes" Zhou says. "In our process, you can form the film evenly down to 20 nanometers because the crystallization at room temperature is much more balanced and occurs immediately over the whole film upon bathing."
While past methods have proven effective in the march of the green movement, Zhou's new techniques may even further drive the movement in that it has the potential to mitigate high costs of solar cells.
Why is this new method such an innovation worth making?
Though solar cells have been made for many years now, the techniques used to date are highly inefficient in terms of production and are contradictory to the green movement in that they require large bursts of heat often obtained by the consumption of fossil fuels.
"People have made good films over relatively small areas-a fraction of a centimeter or so square" Padture says. "But they've had to go to temperatures from 100 to 150 degrees Celcius, and that heating process causes a number of problems."
Zhou's technique may leverage chemical processes to better harness perovskite crystals, but it's not only an innovation in the application of the films. The new study published this week in the Journal of Materials Chemistry A also points towards a bright future for mass production and greater overall efficiency in the process of obtaining solar energy.