Also, you're going to want to incorporate a a diode. Solar panels will flow either direction, so you need a diode to restrict it to one or the other. Simple soldering one inline will fix this problem. Also, you can buy solder glue
online, which works just fine. It's a lot easier than soldering for those who aren't used to it.
Also, simply applying a wire down the middle of the panel is going to significantly decrease your efficiency. To improve this, attach your leads to opposite, diagonal corners. You want your electricity to flow across the panel, and it will always take the path of least resistance. Let me know how it goes, best of luck!