Photovoltaic Cells

Photovoltaic (PV) electricity is generated by using light-sensitive solid-state semiconductor cells. These PV cells or 'solar cells' are grouped together in 'modules'. A PV 'array' is a group of modules that are linked together and are sometimes called 'solar panels'.

PV panels may be attached to the roof or integrated into building components metals roofs, roof tiles, cladding panels and glazing, or even on a separate building.

When these panels are exposed to sunlight (direct and even diffused sunlight), the PV cells (solar cells) within the modules will generate a DC electric current.

Note: because photovoltaic cells generates a direct-current (DC) electricity an inverter will be needed to convert it to an alternating-current (AC) for normal household use.

The most common type of cell used in PV modules or panels are silicon and silicon-based cells of which there are four types:

• Momocrystalline (MC)
• Polycrystalline (PC)
• Thin film Amorphous Silicon (AS)
• Multilayer Amorphous Silicon including the;

• Tandem junction 'double-layer' and
• Triple junction 'three layer'

The most efficient PV cells are the monocrystalline (MC) and the next most efficient are the polycrystalline.

The colour of the MC type PV cells can be dark blue or dark grey. With the PC types the colour is usually a lighter blue, they can however be produced in a range of colours. The multilayer AS cells are generally a reddish black.

Note: be aware that specially coloured cells are generally more expensive and are slightly less efficient than natural coloured cells.