Yet another solar cell breakthrough comes from RoseStreet Labs Energy, Inc (RSLE), who announces a new kind of multiband photovoltaic cell with three distinct light absorption regions, all integrated onto a single-layered thin film. The discovery is based on IBand, a technology proprietary to RSLE and is the first intermediate band solar cell prototyped in a laboratory.
The efficiency of RSLE‘s new thin film solar cell exceeds 35%, because it captures a wider area of the light spectrum. Other research labs have also prototyped wide bandgap solar cells, but not on a single layer and not like this. Their approach rather had several solar cells, each sensitive to a band of the light spectrum, connected in series.
RSLE’s technology makes use of highly mismatched alloys. The simple and elegant three bandgaps, one junction device has the potential of significantly improved solar light absorption and higher power output than the III-V triple junction compound semiconductor devices that presently hold the world record for solar efficiency. RSLE’s demonstration device was fabricated on high volume CVD technology thereby validating the potential for high volume commercialization.
Bob Forcier, CEO, of RSLE, stated, “Although we are three to four years away from high volume production with the IBand product, this development opens up a new class of semiconductor devices for photovoltaic conversion and other advanced semiconductor applications. It fits seamlessly with our Hybrid PV commercialization.”
Wladek Walukiewicz, CTO, of RSLE, announced, “This demonstration is a major breakthrough in our photovoltaic semiconductor roadmap which will allow us to go to the next step in our PV research at an accelerated pace. The IBand technology is synergistic with our thin film Nitride Hybrid product development and will allow upside potential for higher solar conversion efficiencies compared to conventional technologies.”
Although the technology has a long road ahead until commercialization, it’s very interesting to see it evolve, because it represents another pathway towards energy independence. Other high-efficiency approaches make use of concentrated solar power (CSP), which contain mirrors and lenses to focus light on a very expensive but small array of silicon solar cells. Developing cheap and ultra-efficient thin films and applying CSP on them is something definitely worth investigating in terms of price and efficiency.