"Black silicon is produced by irradiating standard silicon with femtosecond laser pulses under a sulfur containing atmosphere," explains Dr. Stefan Kontermann, who heads the Research group "Nanomaterials for Energy Conversion" within the Fraunhofer Project Group for Fiber Optical Sensor Systems at the Fraunhofer Institute for Telecommunications, Heinrich-Hertz-Institut, HHI. "This structures the surface and integrates sulfur atoms into the silicon lattice, making the treated material appear black." If manufacturers were to equip their solar cells with this black silicon, it would significantly boost the cells’ efficiency by enabling them to utilize the full Sun spectrum.
So, the Fraunhofer researchers are planning a spin-off to market the laser system that manufacturers will be able to acquire to expand their existing solar cell production lines. "We hope to be able to increase the efficiency of commercial solar cells – which currently stands at approximately 17 percent – by one percent by combining them with black silicon," Kontermann says.
While Fraunhofer claims are quite similar to ones of SiOnyx, the SiOnyx name has not been mentioned in the article. A year ago SiOnyx reported achieving 0.3% improvement in solar cell efficiency.
0.3% in solar cell efficiency but 300% in QE!
ReplyDeleteMinority carrier lifetime is also critical in these devices. So QE looks great -- lots of absorption. But, low carrier yield.
ReplyDeleteWell there's a surprise! These processes seem like a perfect way of creating surface traps!
DeleteI presume that they do some kind of thermal annealing, or maybe even pinning, after the laser process, but it's hard to imagine that the damage can be repaired.