Solar Photovoltaic Cells

Materials used in construction

Solar Photovoltaic (PV) cells are often made of semiconductor materials, predominantly silicon due to its abundant availability and excellent photovoltaic properties.
Two types of silicon are used: monocrystalline silicon (single crystal structure) and polycrystalline silicon (contains many small crystals), with monocrystalline being more efficient but also more expensive.
A less common but emerging material for photovoltaic cells is thin-film solar cell technology, using materials such as amorphous silicon (a-Si), copper indium gallium selenide (CIGS), or cadmium telluride (CdTe).

Solar cells are designed in a layered structure with a p-n junction formed between p-type and n-type semiconductors which creates an electric field.
The top of the cell has an anti-reflective coating to increase the amount of light absorbed into the cell and a grid pattern of metal conductors to carry the current out of the cell.
A typical solar cell has a silicon semiconductor, a top layer for sunlight to enter, an anti-reflective layer, a space for electrons to move, and a layer on the bottom for electrons to exit.

The manufacturing of a solar cell generally involves several steps including purification of silicon, formation of the crystalline structure, wafer slicing, cell creation, and module assembly.
For thin-film solar cells, the process involves depositing several thin layers on a substrate. This can be done using various methods like chemical vapour deposition (CVD) or physical vapour deposition (PVD).
Final manufacturing step includes application of the metallic conductive grid, assembly into panels and application of an encapsulant for protection.

Solar panels require minimal maintenance, mainly ensuring they are kept clean and in a position to maximize sun exposure.
The lifecycle of a solar cell typically ranges from 20-30 years, depending on factors such as weather, material quality and maintenance level.
Dealing with end-of-life solar cells is a growing concern as it involves the disposal of materials such as glass, aluminium and different types of plastics and metals including potentially hazardous substances like lead.