New material combines photons for big solar energy gains
Extreme Tech, July 28, 2015. Image credit: linushajan
An innovative new approach to solar energy from University of California Riverside could dramatically increase the amount of light available to contemporary solar panel designs. Rather than widening the absorption spectrum of the solar panels themselves, this new study looked at taking currently inaccessible infra-red light and turning it into visible light. They hope that by directing this newly fabricated light onto conventional solar panels, the efficiency of solar power could be greatly improved, for an affordable price.
Infrared light currently passes straight through most silicon solar cell technologies, representing a substantial inefficiency in generating electricity from sunlight. Much of solar research has worked to directly convert infrared light to electricity, but such technologies change the transistor design, and thus the manufacturing process for solar panels. Their impacts tend to be limited by cost concerns, more than anything else.
These researchers chose to accept the absorptive abilities of current silicon transistors, and instead looked to make the light conform to the panels. They created an all-new hybrid material that takes two photons of 980-nanometer infrared light shone onto it and “up converts” them into one photon of 550-nanometer orange/yellow light. This photon has almost double the energy of the originals and, more importantly, it exists in a form that existing solar panels can absorb.
By changing the incoming sunlight into silicon’s favorite for absorption, the material could improve solar panel efficiency by as much as 30%. And while the costs of the material itself are not yet known, there is huge potential in offering such large improvements without the need to completely reinvent the transistor manufacturing process.