Solar panels are very expensive. You will not have enough space on the Jon Boat to accomodate enough of them to power the trolling motor. You'd need about a dozen panels that could deliver one amp or more. That would cost several times what a small outboard would cost. The panels won't work at night or in dim light. You will still need a battery or a battery bank.
There are three basic ways to power a boat. Human power like oars, paddle, or sculling oar. There are some pedal powered possibilities as well. There are a few outfits that make those devices. Then there is sail power. The Jon Boat will sail but not very well. Finally, some kind of mechanical device such as an outboard or electric trolling motor.
There are some other "far out" arrangements for propulsion. Among them is a windmill that is harnessed to an underwater propellor. That rig actually works but it is complex, clumsy, and impractical. Certainly not suited for a Jon boat.
Best bet is to go for the mechanical option. If you choose electric then forget the solar panels. Just use a deep cycle battery and recharge it with household current.