Photovoltaics or PV is the same what we call as solar panels. They absorb energy from sunlight and convert it into electrical energy. Electricity produced on these PV cells is then stored in a battery. Later with the help of a power inverter this electrical energy is used in homes or other buildings to serve the electrical needs. PVs won't run out of electrons. Wear and tear may affect the functioning of photovoltaic cells but generally, it doesn't affect the efficiency of panels or cells.