US researchers have created an energy harvesting smart glass that can also provide glare control.
Scientists from Lawrence Berkeley National Laboratory found that a type of perovskite can be reversibly switched between a transparent and opaque state with no degradation of its electronic properties. When in the opaque state it is able to generate electricity.
The inorganic halide perovskite is triggered to change from transparent to non-transparent through the application of heat or moisture, which alters the material’s crystal structure.
“This class of inorganic halide perovskite has amazing phase transition chemistry,” Berkeley Lab professor Peidong Yang said.
“It can essentially change from one crystal structure to another when we slightly change the temperature or introduce a little water vapour.”
There’s still work to be done, however, with temperatures of about 100°C needed to transition the material, with the team trying to bring this down to 60°C.
Moisture is used to trigger the reverse transition.
“The amount of moisture needed depends on the composition and the transition time desired,” postdoctoral researcher Jia Lin said.
Research will also continue to develop ways to trigger the reverse transition, including applying voltage or engineering a source of moisture.
A recent Berkeley group also created a energy harvesting smart window, though there were issues with performance degradation over time that needed to be smoothed out.
This latest experiment, however, has shown good performance over time.
“The solar cell shows fully reversible performance and excellent device stability over repeated phase transition cycles without any colour fade or performance degradation,” graduate student in Minliang Lai said.
“With a device like this, a building or car can harvest solar energy through the smart photovoltaic window.”
- See Thermochromic Halide Perovskite Solar Cells in Nature Materials.