axil : Mills first idea was to directly convert XUV into current by high power PVC, which are able to convert (1000-1500 times) concentrated sun-light. But Mills lacks some knowledge. He was not aware, that concentrating sunlight will leave the spectrum intact!, whereas the SUN-CELL spectrum is at least 10 time more energetic compared to the suns (on earth!) spectrum.
The only solution would be to find a chemical with a reasonable UV break-up cascade, to down modulate the spectrum into SUN-like regions.
The second mistake he made, was to neglect that he needs a window between the radiation and the PVC and how he could keep this window open. Silver vapor will close down any surface.
This are reasons why products should be developped by engineers not by scientists.
Silver will coat the carbon sphere that faces the plasma.
Based on Layered Composite Thermal Insulation as follows:
A highly insulated N concentric sphere setup that holds CO2 between the spaces between the concentric sphere shells will produce a radiator whose outer surface is at room temperature and its innermost shell is at 3000K.
The innermost shell produces CO2 at 3000K. Outer shells could be made from stainless steel to save cost. CO2 cooled to room temperature returning from the turbine can flow from the outer shells to the innermost shall extracting heat from each shell layer thus cooling each shell layer progressively in turn as the flow of CO2 travels inward. Little heat energy is lost in this setup to the ambient.