What frequencies are they able to redirect to? My understanding that photovoltaics have specific frequency ranges that are more efficient, but the paywalls mean I can’t tell what frequencies they’re currently able to target not how tunable this might be. I can’t imagine it’s visible light because that would seem like press-release gold
Solar cells have a band gap energy which corresponds to a specific frequency of light. Photons below that frequency don’t knock any electrons loose (they just make heat) and photons above that frequency still only knock one electron loose (and the rest of the energy goes to heat). So a single band gap cell is limited to 20-something % max efficiency as a theoretical limit. The ability to re-emit heat at a specific frequency (that could be fed into a cell tuned for that frequency) would be really neat.
I recall an article last week (I think?) about a team managing to get multiple electrons (?) from a single photon, so it seems like would could put everything together and get a decent (overall %) efficiency increase - though I’m sure none of these are particularly close to mass production/deployment
The blackbody temp's they are using (>700C) center around 3um so it's also emitting peaks at lower energy. A graph overlaying the two is prob in the paper but so far I'm not seeing it.
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[ 2.8 ms ] story [ 28.4 ms ] threadMacroscopically Aligned Carbon Nanotubes as a Refractory Platform for Hyperbolic Thermal Emitters
Weilu Gao, Chloe F. Doiron, Xinwei Li, Junichiro Kono, Gururaj V. Naik
https://arxiv.org/abs/1903.06063
The blackbody temp's they are using (>700C) center around 3um so it's also emitting peaks at lower energy. A graph overlaying the two is prob in the paper but so far I'm not seeing it.