Berkeley chemists devised a new type of photovoltaic out of cesium-doped perovskite that not only provides power but also doubles as a tinted window. At room temperature, the solar cell is transparent but automatically tints once the temperature rises, blocking the sun, thereby cooling the space behind the window, and generating electricity at the same time.
Peidong Yang and colleagues at Berkeley Lab described their creative solar cell in the journal Nature Materials. Yang thinks the invention could be used for smart windows or displays in the buildings, vehicles, and the handheld devices of the future.
“This class of inorganic halide perovskite has amazing phase transition chemistry,” Yang said. “It can essentially change from one crystal structure to another when we slightly change the temperature or introduce a little water vapor.”