Solar Cell

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Solar Cells.

Introduction.

Solar cells are electrical devices that use the photovoltaic effect to convert light energy into electricity.

Edmund Becquerel first used the photovoltaic effect in 1939. He found that an electric current occurs when the light hit a silver coated electrode immersed in an electrolyte. 40 years after, robust photovoltaic devices were made to investigate a discovered photoconductivity of Selenium. Later in 1984, a scientist called Charles Fritts made the first solar cell using Selenium and Gold. Fritts compressed a layer of the selenium between the gold and another metal. In the later years, photovoltaic effects were made using copper oxide, lead sulphide and thallium sulphide.

Later in the 1950's, silicon electronics were developed. It followed discoveries of ways to make p-n junctions in the silicon. In 1954, cadmium sulphide was used to produce p-n junctions. However, in the later years, other compounds were use. They included gallium arsenide, cadmium telluride and indium phosphate. All through, silicon has remained the most preferred photovoltaic component.

In the 1990s, photovoltaic interest grew due to the high prices of fossil fuels as a source of electricity.

How solar cells work.

A solar cell comprises the following components:

* Encapsulate – made of glass or any other transparent material that allow light to pass through.

* Contacts – The contacts are made up of a good conductor of electricity. They are used to collect the electrons. The contacts are often Aluminum.

* Anti-reflective coating (ARC) – Due to the high reflectivity of Silicon, a layer of low reflectivity is required. The layer contains dielectric materials with a combination of precise thickness and refractive index. The layer prevents light from bouncing off the surface by causing the reflected waves of light to interfere destructively.

* N-type – made of silicon. The silicon is highly doped (contaminated)...