Photovoltaic cells

Photovoltaic cells are made using the same materials used to make semiconductors, such as silicon.

The cell converts solar energy into electricity using the photovoltaic or Hertz effect. The term solar cell is used for cells made specifically for capturing energy from the sun and reffered to as a photovoltaic cell when the source is not defined.

Cells have developed in three ways, called 'generations' in the industry. the first generation cells feature large-area, single junction systems. First generation devices still represent the majority of this type of equipment available on the market.

The second and third generations feature newer technology, but have yet to prove themselves on the market.

Second generation devices feature several successful materials: cadmium telluride (CdTe), copper indium gallium selenide (CIGS), and amorphous and micromorphous silicon applied as a thin film onto a supporting medium.

Third generation systems are still highly experimental and in the research and development stage. Innovations include non-silicon-based cells using materials such as nanocrystalline, polymer, and dye-sensitized cells. Also, third generation cells won’t need the p-n junction needed by traditional, silicon-based semiconductors.

Photovoltaic cells are just the smallest part of these incresible technologies. Groupings of cells are used to make solar modules, solar panels or photovoltaic arrays. Cells are fit together to form modules. Modules are then wired together, parallel or in series, to form a solar array.

In the case of solar cells, an electric field is formed by a thin semiconductor wafer that has been specially treated to form a positive field on one side and a negative field on the other. When light (energy) hits the solar cell, the semiconductor material come alive - electrons are knocked loose from the atoms inside. Electrical conductors can then be attached to the positive and negative sides.