Does the Martian atmosphere filter out certain frequencies of light? And how does it compare against the frequencies that their rover solar panel is sensitive to? Or is their atmosphere thin enough such that UV light gets through? Can they make use of that?

Lots of questions just about their solar panels and what would be the most effective chemicals to make their solar panels out of to maximize their output.

They have no probes previously on the surface of Mars. How would they know how to make their solar panels to be the most efficient without data? Did they just guess? Did NASA share that information? Or is that secret information that NASA kept quiet and Chinese spies stole that information?

All three possibilities could have occurred but I really doubt that China would just guess and then spend billions of dollars to send a probe without knowing if it would work.