If I flash a UV flashlight at a small solar panel that charges mobile devices, would it work?

Hey Fenn, no, it wouldn't "work." Solar panels do not make use of visible light when converting the sun to electricity, they use the particles called photons, which cause a reaction between the two layers of silicon in the panel, forcing electrons from one layer onto the other. You can get a small current from a panel if you hold it near a campfire, I tried that once, but over a short time the panel becomes hot enough to damage it, so long term it isn't a good solution either. Even if they did make a flashlight that emitted photons in mass amounts like the sun does, panels only convert around 12 % of the energy to electricity. It would be so much easier to just use the batteries in the flashlight to charge your phone directly. That can be done pretty easily by the way. If you had enough AA or AAA or C or D cells to make about 7.5 volts, that would be 5 of them in line, and ran the power through a car type USB charging converter from the store, it would happily convert the 7.5 volts to 5 volts. It might work with 4 cells, but not for very long, there has to be a small over voltage for that converter to work. You could also try using 3 AA cells in line connected directly to the phone, that would give you around 4.5 volt, close to 5, but depending on the phone it might not charge all the way up. Take care Fenn, Rudydoo