The junction that gives charges a direction
A solar cell is built from semiconductor layers arranged so that an internal electric field forms where they meet. When light delivers enough energy to the material, an electron can move into a mobile state, leaving behind an electron hole—a place where a negative charge is missing. The electron and hole are created together, but they can move separately.
The junction’s field pushes them in opposite directions: electrons toward one side of the cell and holes toward the other. This separation matters because, without it, many charges would quickly meet again and release their energy as heat or light instead of contributing to useful electricity.
From separated charges to a working circuit
Metal contacts collect charges at the cell’s two sides. Connect those contacts through a device, and electrons travel through the outside wire from one side to the other, powering the device along the way. Inside the cell, charge movement completes the circuit. The electron’s route is not a stream of light carried through the panel; light supplies energy that sets charges in motion.
A cell’s voltage comes from the difference in electrical conditions between its two contacts, while its current depends on how many charges are moving. The panel’s job is therefore twofold: separate light-excited charges inside the semiconductor, then provide a route for them to do work outside it. That is why a solar panel can power a lamp even though the photons that started the process never travel through the lamp’s wire.
