Smart windows could block brightness and harness light
New material pulls double-duty as shade and perovskite solar cell
![window pane samples](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2018/02/020618_MT_teaser_perovskite_main.jpg?fit=860%2C460&ssl=1)
SOAKIN’ UP SUN New materials can switch from transparent pane (right) to dark-tinted solar cell (left) and back again.
Jia Lin/U.C. Berkeley