Solar Cells

• Solar cells are made of two types of silicon

• Normal silicon has no free electrons

• N-type silicon has been doped with phosphorus to give it extra electrons

• P-type silicon has been doped with boron to give it extra “holes” for electrons to be in

Semi-conductors and doping

N-type P-type

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N-type P-type

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Photons of light energy

• As more electrons on in the n-type silicon absorb photons of energy more can make the jump and move through the p-type silicon

• These moving electron cause a current to flow in a circuit connected as shown