Thank you. I think this was helpful!

Can I ask if the final entry about photoelectric output from high energy X-Rays is basically using the Xrays to energise emission of photons which are then captured using PV cells? Or is it an analogous pathway to DC voltage from a PV cell tuned to high energy Xray energy?

I kind of hoped it was 'X ray in, optics out' because that would be enormously entertaining: We could run PV cells at night. The "no green energy when the sun doesn't shine" is fixed by .. shining your own suns.

What was missing as well, was the comparison to thermal efficiency. I am pretty sure direct extraction even with its losses is ahead, but couldn't see this in the article.