Neat, this seems very similar in concept to how the difference between fluorescence and phosphorescence is usually explained. They just observed it with electron-hole recombination instead of light emission.
So, not an entirely unknown concept, but in a field of material research it has not been seen before. Sounds like a solid basis to go looking for new materials for photovoltaics, now that we know what to look for in candidates.
https://www.nature.com/articles/s41586-026-11223-x
Abstract
Kirchhoff demonstrated the reciprocity between absorptivity and emissivity for blackbody radiation in 1860 (ref. 1), thereby establishing the general principle that a good absorber must also be a good emitter. This principle underpins the generalized Planck’s law2 and, when applied to semiconductors—in the form of the van Roosbroeck–Shockley equation3—results in substantial limitations to solar energy conversion. Here we demonstrate how this reciprocity can be circumvented in semiconductors, such as bismuth sulfide, showing a pseudo-direct bandgap character—that is, featuring a lower-energy indirect transition paired with a direct transition placed a few kBT above. After determining the pseudo-direct bandgap nature of bismuth sulfide, we reveal how this feature substantially retards bimolecular electron–hole recombination in this material with respect to classic direct semiconductors4. The resulting combination of a high absorption coefficient and delayed recombination offers the unprecedented possibility of overcoming limitations associated with Planck’s law, with far-reaching potential for solar energy conversion.
Hoping for new tech that will significantly improve PV power generation. Any guess as to how much improvement this might imply? With as much as I know, I’m not even sure that abstract is in English. :-D
I would expect more from multijunction cells. Wikipedia has a very nice article https://en.wikipedia.org/wiki/Solar_cell_efficiency
Yet again semiconductors adding asterisks to physics lecture.
“This is ohms law, and it does these things* except for an-ohmic devices like diodes and semiconductors… they don’t give a shit about ohms law”
“This black body radiation and absorption, it works like this* except for these weird combinations of semiconductors and coatings, which is an exception now.”
From the article towards the end, ‘Further work is now needed to translate these findings into improved solar cell technologies.’
Still great research though
It takes time, but promising imo
I think the panels on my home are around 20% efficient so this sounds promising.
