I have a mosquito lamp that runs off a solar panel or it can run with a USB-C. I don't need the solar panel so I thought I would keep it in my emergency supplies to power a cell phone if needed. The solar panel doesn't have a USB output. Is there some kind of conversion item I could use to plug the solar power plug into a USB wire?
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A USB-powered device expects a constant-voltage power supply. A USB power brick uses any of several different protocols to advertise how much current it is able to supply, and it may be possible for the device to negotiate with the brick for the supply voltage (5V, 9V, or 12V.)
A bare array of solar cells doesn't know anything about "protocols." It provides voltage-limited constant current, with the amount of current dependent on the intensity of illumination, and the voltage limit being entirely application-dependent. It's hard to say whether what you've got there is a bare array, but it's likely that that's what you have.
Assuming that the solar panel is even capable of supplying enough power to charge your device, then you probably would need some kind of electronic "converter" circuit to do it safely and effectively.
P.S., Portable, USB-compatible, solar chargers are a thing you can buy on Amazon for not too much money. The one I bought is about 11 inches by 30 inches when it's deployed, or 11 x 7.5" when folded up. It allegedly can provide 30W of power in full Sun, though in my neck of the woods, 20W on a sunny spring or fall afternoon is more realistic. That's enough to charge two cell phones at "normal" (i.e., not "rapid") speed at the same time.
