If I had a strong source of radio-frequency photons, can these be converted to electricity like a solar panel does for light?
That would be an antenna or a coil, if you’re trying to harvest electromagnetic fields.
Samsung had a remote that did this, actually.
https://www.tomsguide.com/news/samsungs-new-eco-remote-charges-via-wi-fi-forget-aa-batteries
Yes, these devices exist. But, IR is significantly, even several orders of magnitude, less powerful from the sun than visible and UV light. The only applications derive from receiving power from human sources that are bright enough, some examples are here in the other comments.
Even then, I have doubts that human IR emitters produce enough power for anything but the most highly efficiently engineered device, outside of a microwave.
