The ceramic-coated emitters were sent to Fan and his colleagues at Stanford, who confirmed that devices were still capable of producing infrared light waves that are ideal for running solar cells.
CEO of the BOD Group, Vidmantas Janulevicius, added: “In commissioning this plant we are very proud to be supporting the goals of expanding renewables in Lithuania, in this specific case photovoltaics.
“Essentially, we tailor the light to shorter wavelengths that are ideal for driving a solar cell,” Fan said. “That raises the theoretical efficiency of the cell to 80 percent, which is quite remarkable.”
I think what Dr. Gupta is saying here is that we should just forget solar power entirely and start feeding our robots meat. But until that happens, continuing advances in solar cell technology should allow Robo Raven to at least significantly extend its flying time, if not power itself from the sun completely.
“In theory, conventional single-junction solar cells can only achieve an efficiency level of about 34 percent, but in practice they don’t achieve that,” said study co-author Paul Braun, a professor of materials science at Illinois. “That’s because they throw away the majority of the sun’s energy.”
In previous experiments, however, the 3D structure of the emitter was destroyed at temperatures of around 1800 F (1000 C). To address the problem, Braun and his Illinois colleagues coated tungsten emitters in a nanolayer of a ceramic material called hafnium dioxide.