Question: How does graphene convert light into electricity?

Lewis Wright answered on 5 Mar 2017:

Semiconductors are materials that are halfway between a conductor (like copper wire in cables) and insulators (like wood, plastic, stone, anything that doesn’t conduct electricity).
Graphene is a semiconductor made only from carbon, and has a very special shape – it is a layer just one atom thick!

Electricity is the flow of electrons that have absorbed energy. When a semiconductor has light shined onto it, the energy from the photon is absorbed by the electron, which then has enough energy to escape from the atom it was trapped around. Once it can move more freely, the energetic electrons are separated completely from the atoms they came from, and are directed down a wire to power whatever is waiting at the other end.
Like all circuits, it must form a loop – so electrons with lots of energy flow away from the solar cell, use up their energy to power something, and then come back again once they have lost all their energy. Because they dont have the energy to move away from an atom (which attracts electrons like a magnet), the electrons sit around an atom again, waiting for another photon to absorb and to do the whole process again!

Good question!