A research team from the Ulsan National Institute of Science and Technology (UNIST) in South Korea has developed transparent solar cell technology capable of directly charging a battery from a glass surface. This innovation offers numerous applications, allowing for direct energy generation from sources like smartphone screens, car windows, and building facades.
Solar panels on your roof won’t do much good if you’re off grid and need to charge your phone. Just get a small, folding solar panel that you can carry in your backpack. A 10W panel will only need a couple hours of direct sunlight to fully charge a phone.
Even having a panel covering your backpack would be a good idea.