Researchers explored the possibility of charging low-power rechargeable devices using high-efficiency photovoltaic modules that capture ambient indoor lighting.
Solar panels are getting more and more efficient, and researchers are now trying to gain a significant amount of energy from ambient indoor lighting for low-power devices.
Andrew Shore and Behrang Hamadani, from the National Institute of Standards and Technology, presented their findings on the capabilities of indoor solar cells in generating power under an LED at the AIP Publishing Horizons — Energy Storage and Conversion virtual conference.
Researchers used a white LED with a color coordinate temperature of 3,000 K and an illuminance of 1,000 lux as a lighting source to test three different modules: a gallium indium phosphide (GaInP) semiconductor, a gallium arsenide (GaAs) semiconductor, and a silicon (Si) semiconductor.
“Under these light settings, the GaInP mini module performed with the highest power conversion efficiency, followed by the GaAs mini module, with the Si mini module as the lowest performer,” Shore said. “The GaInP and GaAs modules have a better spectral match with this visible-spectrum LED light source.”
He added that GaInP would require the least amount of light and still maintain high efficiency, but not all indoor light sources are LEDs.
“Different light sources have different spectra,” he said. “For instance, an incandescent light source has a large portion of its irradiance in the near infrared region. Fluorescent lights have several spikes in intensity at different places in the visible spectrum. LED lights generally have one short, prominent peak around 450 nanometers and another more gradual peak around 600 nm. Each of these light sources will affect the power conversion efficiency of the photovoltaic technology.”