The Man
Unbanned zombie poster
Since you're speaking in the present tense about these cells, their efficiency and cost, are we to presume that these cells exist now?
I think he is talking about multi-junction solar cells,
https://en.wikipedia.org/wiki/Multi-junction_solar_cell
Basically broad spectrum photovoltaics,
While confusing it with the concentrator photovoltaics systems that use such broad spectrum cells.
https://en.wikipedia.org/wiki/Concentrator_photovoltaics
The whole idea behind concentrator photovoltaics is that light that falls over a larger area is, well, concentrated onto the smaller area of the solar cells. Not really an issue if you plan to just encompass the entire light source.
I think due to the improved efficacy due both to the larger collection area and broader spectrum cells, someone just latched onto the name of the system without actually looking into it and finding the actual name of the cells.