Monocrystalline silicon
Silicon grown as a single continuous crystal, usually by the Czochralski method, giving the highest-efficiency and now dominant wafer type for PV.
Monocrystalline silicon wafers are sliced from a cylindrical ingot pulled from molten polysilicon by the Czochralski process. Because the lattice is continuous, there are no grain boundaries to trap charge carriers, so carrier lifetimes are long and cell efficiencies high. Cells are recognisable by their uniform dark colour and, with older square-cut wafers, chamfered corners.
Monocrystalline wafers overtook multicrystalline material around 2019 as diamond-wire sawing and larger ingot pullers cut costs. By 2023 they accounted for more than 95% of global wafer production (ITRPV, 2024). The industry has also shifted from boron-doped p-type to phosphorus-doped n-type wafers, which do not suffer boron-oxygen light-induced degradation and suit TOPCon and heterojunction architectures.
- Typical commercial module efficiency: 21–23.5% (2024–2025).
- Wafer thickness: about 130–150 µm, down from over 180 µm a decade ago.
- Energy-intensive step: polysilicon refining and ingot growth, the main driver of energy payback time.
The higher efficiency means fewer modules, less racking and less land per kWp, which lowers balance-of-system costs.
Related terms
All terms →- Polycrystalline silicon
Silicon cast into blocks containing many small crystal grains; cheaper to make than monocrystalline but less efficient, and now largely phased out of PV production.
- Solar cell
A semiconductor device, usually a doped silicon wafer with metal contacts, that converts sunlight directly into direct-current electricity via the photovoltaic effect.
- TOPCon
Tunnel Oxide Passivated Contact: an n-type silicon cell whose rear uses an ultra-thin oxide and doped polysilicon layer to extract current with minimal recombination.
- PERC (Passivated Emitter and Rear Cell)
A silicon cell design that adds a passivating dielectric layer to the rear surface, reducing recombination and reflecting light back into the cell.
- Energy payback time
The time an energy system must operate to generate as much energy as was used to manufacture, install and decommission it.