Polycrystalline PV cells
Polycrystalline PV cells are manufactured from multicrystalline silicon. They are easier and cheaper to make, but efficiency is reduced to around 14%.
This type of PV is sometimes called ‘multi-crystalline’ or ‘semi-crystalline’.
Monocrystalline PV cells
Most solar PV cells are manufactured using silicon. High efficiencies of 17% are possible using very pure monocrystalline silicon but prices can be high.
A lower grade of silicon – ‘solar grade’ – which is less pure and less costly is often used with little reduction in efficiency
Thin film PV cells
Developments of thin film silicon – 'amorphous silicon' (a-Si) – mean it is now possible to produce both rigid and flexible a-Si PV modules. Manufacturing is cheaper and less energy intensive but efficiencies are generally lower and can degrade rapidly.
Non-silicon thin film PV products often do better, achieving more
stable efficiencies of over 10%.