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.
You could look at it another way- a solar power screen on a phone won’t charge it all the way, but as a secondary source of power that is essentially always on when the sun is up or other light sources are on, it reduces the battery drain over the day, meaning less charging needed at night.
It’s so tiny that it’s a waste of time and money. Most phones can charge in an hour now, so there’s no need to shave 60s off a night charge by exposing your phone to the sun all day.
Carry a power bank if you are constantly draining your phone all day.