Most people spend a majority of their days indoors, where sunshine is not easily available. Instead, there is white light from LEDs and fluorescent bulbs. So what if you could charge your electronics and devices using that artificial light?
In a new study published in APL Energy, researchers report a new type of solar cell that can convert almost 39 percent of indoor light into electricity. The solar cells can also produce electricity from sunlight on cloudy days.
Solar panels that dot rooftops and cover swaths of land at solar farms are made of silicon. In the past decade, though, researchers have made enormous progress on solar cells made of perovskite materials. Perovskite solar cells are much easier to make than silicon devices. And unlike rigid, heavy silicon solar panels, perovskite devices can be made thin, lightweight, and flexible.
Most importantly, perovskites have a higher efficiency than silicon. So they can convert low levels of light into usable amounts of electricity.
The part of the light spectrum, or wavelengths of light, that a photovoltaic material can absorb depends on a property called bandgap. This is the gap that electrons in the material have to jump across when they absorb light and get excited.
Researchers from National Yang Ming Chiao Tung University adjusted the bandgap of their solar cells so that it is tuned more closely with the wavelengths of light from artificial light sources. To do that, the team adjusted the ratios of the perovskite molecules in the solutions that they used to make the solar cell. This type of bandgap adjustment is not possible with silicon solar cells.
Tests showed that this worked. Under simulated sunlight with an intensity of 12,000 lux, the perovskite cells achieved an efficiency of 12.7 percent. The best silicon solar cells, by comparison, have an efficient of 26 percent. However, under a much lower 2,000 lux brightness—about the level found in a standard office space—the perovskite solar cells had an efficiency of 38.7 percent.
Source: Chia-Tse Hsu, Ching-Wei Lee and Fang-Chung Chen. Chelating agent-based defect passivation for enhanced indoor performance of wide-bandgap perovskite solar cells, APL Energy, 2025.
