Scientists have discovered a new material for next-generation smart windows that will not only get a tinted look when the Sun is too bright but will also convert solar energy into electricity.
The discovery was made by researchers at the Lawrence Berkeley National Laboratory (Berkeley Lab) in the United States. The researchers discovered a form of perovskite that works well as a stable and photoactive semiconductor material that can reversibly switch between transparent and non-transparent state, without degrading its electronic properties.
• The scientists made the discovery while investigating the phase transition of the material, an inorganic perovskite.
• The inorganic halide perovskite can essentially change from one crystal structure to another with a slight change in the temperature or when it is introduced to a little water vapour.
• When the material changes its crystal structure, it changes from transparent to non-transparent.
• The Halide Perovskite materials are compounds that have the crystal structure of the mineral perovskite.
• Its unique properties, high efficiency rates and ease of processing have made it one of the most promising developments in solar technology in recent years.
• The researchers were investigating phase transitions in perovskite solar cells and trying to improve the stability in the prototypical organic-inorganic hybrid perovskite methylammonium lead iodide.
• They tried using cesium to replace the methylammonium. Though the chemical stability improved dramatically, but unfortunately the phase was not stable.
• So the scientists turned to something that's unique and useful.
• The Halide Perovskite material is triggered to transition from transparent to non-transparent by applying heat.
• In the lab, the temperature required was about 100 degrees Celsius. Moisture or humidity was used to trigger the reverse transition.
• The researchers will also continue to work on developing alternative ways to trigger the reverse transition, such as by applying voltage or engineering the source of the moisture.
Such a device would enable a building or a car to harvest solar energy through the smart photovoltaic window.