Researchers led by UCL have developed durable new solar cells capable of efficiently harvesting energy from indoor light, meaning devices such as keyboards, remote controls, alarms and sensors could be battery free.

The team used perovskite, which is increasingly used in outdoor solar panels and, unlike traditional silicon-based solar panels, has 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 which can cause electrons to get stuck before their energy can be harnessed. However, in a study published in the journal Advanced Functional Materials, the team describes how it used a combination of chemicals to reduce these defects, potentially making perovskite indoor solar panels viable.

Senior author Dr Mojtaba Abdi Jalebi (associate professor at the UCL Institute for Materials Discovery) said: “Billions of devices that require small amounts of energy rely on battery replacements, an unsustainable practice. This number will grow as the Internet of Things expands. The advantage of perovskite solar cells is that they are low-cost, they use materials that are abundant on Earth and require only simple processing. They can be printed in the same way as a newspaper.”

The team found that the solar cells converted 37.6 per cent of indoor light (at 1000 lux or the equivalent to a well-lit office) into electricity, a world record for this type of solar cell optimised for indoor light, that is with a bandgap of 1.75 eV.

The team involved researchers from the UK, China and Switzerland.

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