An international team led by UCL researchers has developed durable new solar cells capable of efficiently harvesting energy from indoor light, meaning that devices such as keyboards, remote controls, alarms and sensors could soon be battery-free.

The team used a material called perovskite, which is increasingly used in outdoor solar panels, and unlike traditional silicon-based solar panels, has the potential to be used indoors as well as its composition can be adjusted to better absorb the specific wavelengths of indoor light.

A major drawback of perovskite, however, is that it contains tiny defects in its crystal structure —known as traps—that can cause electrons to get stuck before their energy can be harnessed. These defects not only interrupt the flow of electricity but also contribute to the material’s degradation over time.