This news is classified in: Sustainable Energy Solar
Jan 22, 2018
Smart windows that are transparent when it’s dark or cool but automatically darken when the sun is too bright are increasingly popular energy-saving devices. But imagine that when the window is darkened, it simultaneously produces electricity. Such a material – a photovoltaic glass that is also reversibly thermochromic – is a green technology researchers have long worked toward, and now, scientists at Lawrence Berkeley National Laboratory (Berkeley Lab) have demonstrated a way to make it work.
Researchers at Berkeley Lab, a Department of Energy (DOE) national lab, discovered that a form of perovskite, one of the hottest materials in solar research currently due to its high conversion efficiency, works surprisingly well as a stable and photoactive semiconductor material that can be reversibly switched between a transparent state and a non-transparent state, without degrading its electronic properties.
The research, led by Peidong Yang of Berkeley Lab’s Materials Sciences Division, was published this week in the journal Nature Materials in a study titled, “Thermochromic Halide Perovskite Solar Cells.” The lead authors were Jia Lin, Minliang Lai, and Letian Dou, all in Yang’s research group.
The scientists made the discovery while investigating the phase transition of the material, an inorganic perovskite. “This class of inorganic halide perovskite has amazing phase transition chemistry,” said Yang, who is also a professor in UC Berkeley’s departments of Chemistry, and Materials Science and Engineering. “It can essentially change from one crystal structure to another when we slightly change the temperature or introduce a little water vapor.”
When the material changes its crystal structure, it changes from transparent to non-transparent. “These two states have the exact same composition but very different crystal structures,” he said. “That was very interesting to us. So you can easily manipulate it in such a way that is not readily available in existing conventional semiconductors.”
