A study reveals that green materials being prepared to upgrade solar panels can power smart devices at home and office

A team of researchers has discovered that new green materials currently being developed for next-generation solar panels could be useful for indoor light harvesting, paving the way to power smart devices using ambient light at home or office.

In smart devices like smartphones, smart speakers and wearable health and wellness sensors, the can deplete quickly and contain toxic and rare environmentally damaging chemicals. One way to power them is by converting indoor light from ordinary bulbs into energy, in a similar way to how solar panels harvest energy from sunlight, known as solar photovoltaics.

However, due to the different properties of the light sources, the materials used for solar panels are not suitable for harvesting indoor light.

Now, researchers from Imperial College London, Soochow University in China, and the University of Cambridge have detailed a novel way in a paper published in the journal Advanced Energy Materials. “By efficiently absorbing the light coming from lamps commonly found in homes and buildings, the materials we investigated can turn light into electricity with an efficiency already in the range of commercial technologies,” explained study co-author Dr Robert Hoye from the Department of Materials at Imperial. He added, “We have also already identified several possible improvements, which would allow these materials to surpass the performance of current indoor photovoltaic technologies in the near future”.

The team investigated ‘perovskite-inspired materials’, which were created to circumvent problems with materials called perovskites, which were developed for next-generation solar cells. Although perovskites are cheaper to make than traditional silicon-based solar panels and deliver similar efficiency, perovskites contain toxic lead substances.

This drove the development of perovskite-inspired materials, which are instead based on safer elements like bismuth and antimony. The team found that the materials are much more effective at absorbing indoor light, with efficiencies that are promising for commercial applications.

Crucially, the researchers demonstrated that the power provided by these materials under indoor illumination is already sufficient to operate electronic circuits. Professor Vincenzo Pecunia, from Soochow University, said: “Our discovery opens up a whole new direction in the search for green, easy-to-make materials to sustainably power our smart devices”.

Lead-free perovskite-inspired materials could soon enable battery-free devices for wearables, healthcare monitoring, smart homes, and smart cities, the authors wrote.