**2. History of photovoltaic effect**

The photovoltaic effect was discovered in 1839 by the French physicist, Alexandre Edmond Becquerel. While experimenting with metal electrodes and electrolyte, he discovered that conductance increases with illumination. Willoughby Smith discovered the photovoltaic effect in selenium in 1873. Albert Einstein described the phenomenon in 1904. The first silicon monocrystalline solar cell was constructed in 1941. In 1951, the first germanium solar cells were made. Bell's Laboratories published the results of the solar cell operation with 4.5% efficiency. The efficiency was increased to 6% within a few months. In 1957, Hoffman Electronics introduced a solar cell with 8% efficiency. A year later, in 1958, the same company introduced a solar cell with 9% efficiency. The first radiation-proof silicon solar cell was produced for the purposes of space technology in the same year. In 1960, Hoffman Electronics introduced another solar cell with 14% efficiency. In 1977, the world production of photovoltaic modules exceeded 500 kW. In 1984, ARCO Solar introduced the first amorphous modules. In 1985, researchers at the University of New South Wales in Australia constructed a solar cell with more than 20% efficiency. In 1996, BP Solar purchased APS announced a commercial CIS solar cells production. During 2000 and 2001, the production by Japanese manufacturers increased significantly.

**4. Basic structure of a solar cell**

**Figure 2.** Incident light on a typical PN solar cell.

Most solar cell technologies [3] have:

tion and does not need to be transparent.

**5. Equivalent circuit of a solar cell**

usually made of metals.

light is absorbed.

side.

• Anti-reflecting coating (ARC), which is a very important part in solar cell fabrication. It is usually sprayed over bare silicon cell because silicon has a high surface reflection.

Introductory Chapter: Introduction to Photovoltaic Effect

http://dx.doi.org/10.5772/intechopen.74389

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• Front contacts that are necessary to collect the current generated by a solar cell. They are

• An emitter that absorbs the incoming photons and transports their energies to the excited state of charge carries. Pentavalent-doped silicon (n-type) has a higher surface quality than trivalent doped silicon (p-type), so it is placed at the front of the cell, where majority of the

• In p-n junction, in its simplest form, the base (p-type) region is joined at a junction with emitter (n-type) region leading to majority electrons in the n-type side close to the junction to diffuse of to the p-type side and majority hole from the p-type to diffuse n-type

• Rear contact is a less important than the front contact because it is much way from the junc-

To understand the electronic behavior of a solar cell, it is useful to create a model, which is electrically equivalent and is based on discrete electrical components whose behavior is well known. An ideal solar cell may be modeled by a current source in parallel with a diode;
