Solar Photovoltaic Cells

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).

Design & Structure

  • 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.

Manufacturing Process

  • 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.

Maintenance & Life Cycle

  • 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.