Charging Devices With Indoor Lighting: Office Lights Power Electronics todayheadline

Scientists have engineered solar cells that harvest energy from fluorescent lights and LED bulbs, achieving nearly 40% efficiency under typical office lighting.

The perovskite-based devices could revolutionize how we power small electronics, making everything from remote controls to wearable devices energy-independent indoors.

Researchers from National Yang Ming Chiao Tung University in Taiwan developed these specialized solar cells by fine-tuning their light-absorption properties and fixing structural defects that typically plague wide-bandgap perovskite materials.

Indoor Lighting Efficiency Breakthrough

Under standard outdoor sunlight conditions, the team’s perovskite solar cells achieved a respectable 12.7% power conversion efficiency. But their real strength emerged under dim indoor conditions—reaching an impressive 38.7% efficiency at 2,000 lux, roughly equivalent to bright office lighting.

This indoor performance far exceeds what traditional silicon solar panels can achieve in similar conditions. “The indoor efficiency of PeSCs is higher, meaning that the photovoltaic products can be more suitable for versatile user scenarios, including cloudy outdoor, indoor, and other dim-light environments,” explains lead researcher Fang-Chung Chen.

The key innovation lies in bandgap engineering—adjusting the energy levels at which the material absorbs light. By modifying the ratio of iodine to bromine ions in their perovskite formula, the researchers optimized absorption for indoor light spectra rather than bright sunlight.

Solving the Defect Problem

Creating wide-bandgap perovskite materials typically introduces structural defects that reduce efficiency. The research team addressed this challenge using chelating agents containing phosphorus-oxygen bonds, particularly a compound called PPF (2,8-bis(diphenyl-phosphoryl)-dibenzo[b,d]furan).

These chelating agents, added during the manufacturing process, effectively “passivate” surface defects by binding to uncoordinated lead ions in the perovskite structure. The treatment resulted in several measurable improvements:

• Reduced surface roughness from 4.31 nm to 2.77 nm
• Lower trap density in the material structure
• Enhanced charge transport properties
• Improved long-term stability with only 6% efficiency loss after 500 hours

Practical Applications

Unlike rigid silicon panels, perovskite solar cells can be manufactured as thin, lightweight, flexible films. “PeSCs can be made thin, lightweight, flexible, and even semi-transparent, whereas silicon panels are rigid and heavy, which limits their use to flat, durable surfaces,” Chen notes.

This flexibility opens applications for Internet of Things devices, wearable electronics, and portable gadgets that need continuous low-power operation. The technology could eliminate battery replacement for countless small devices in homes and offices.

The research involved testing under two common indoor light sources: fluorescent tubes and white LED lights at various brightness levels. Both showed consistent performance, with efficiency generally increasing at higher illumination levels typical of well-lit indoor spaces.

Addressing Stability Concerns

Stability has long been a challenge for perovskite solar cells, but the defect passivation strategy unexpectedly improved this weakness. “In the beginning, we only expected our approach could improve the device efficiency,” Chen admits. “Because the poor reliability of PeSCs is a large challenge for their adoption, we hope our proposed method can pave the way toward the commercialization of perovskite solar panels.”

The team tested device stability using maximum power point tracking over 150 minutes and long-term storage under ambient conditions. The PPF-treated devices maintained performance significantly better than untreated controls, suggesting the approach addresses multiple limitations simultaneously.

As buildings worldwide seek energy-efficient solutions and portable electronics proliferate, these indoor-optimized solar cells could provide sustainable power for the growing array of connected devices that populate modern environments.

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