Solar Cell Materials - An Overview of Solar Cell Materials

Materials Used for the Construction of Photovoltaic Cells
Silicon - The Most Popular Material for Solar Cells
Polycrystalline Thin Films - Reducing Material Required in Solar Cells
Copper Indium Diselenide
Cadmium Telluride
Gallium Arsenide

Photovoltaic cells, more commonly known as solar cells, are found in applications such as calculator and satellites. First used almost exclusively in space, photovoltaic cells are used in more common applications. In simple terms, photovoltaic cells and devices convert light energy into electrical energy. Photovoltaic cells are available in many different shapes and sizes. When individual photovoltaic cells are joined, they form photovoltaic modules.

Materials Used for the Construction of Photovoltaic Cells

Special materials are used for the construction of photovoltaic cells. These materials are called semiconductors. The most commonly used semiconductor material for the construction of photovoltaic cells is silicon. Several forms of silicon are used for the construction; they are single-crystalline, multi-crystalline and amorphous. Other materials used for the construction of photovoltaic cells are polycrystalline thin films such as copper indium diselenide, cadmium telluride and gallium arsenide.

Silicon - The Most Popular Material for Solar Cells

A number of the earliest photovoltaic (PV) devices have been manufactured using silicon as the solar cell material and it is still the most popular material for solar cells today.

The molecular structure of single-crystal silicon is uniform. This uniformity is ideal for the transfer of electrons efficiently through the material. However, in order to make an effective photovoltaic cell, silicon needs to be "doped" with other elements.

Multi-crystalline silicon is normally considered less efficient than single-crystal silicon. On the other hand, multi-crystalline silicon devices are less expensive to produce. Casting process is the most common means of producing multi-crystalline silicon on a commercial scale.

Amorphous silicon can absorb 40 times more solar radiation than single-crystal silicon. This is one of the main reasons why amorphous silicon can reduce the cost of photovoltaics. Amorphous silicon can be coated on low-cost substrates such as plastics and glass. This makes amorphous silicon ideal for building-integrated photovoltaic products.

Polycrystalline Thin Films - Reducing Material Required in Solar Cells

Numerous thin-film technologies are currently being developed to decrease the amount of light absorbing material required to produce solar cells. This could lead to a reduction in the processing costs; however it could also lead to a reduction in the energy conversion efficiency.

Copper Indium Diselenide

Copper indium diselenide or CIS for short, has an extremely high absorptivity. This means that 99% of the light illuminated on CIS will be consumed in the first micrometer of the material. The addition of a small amount of gallium will improve the efficiency of the photovoltaic device. This is commonly referred to as copper indium gallium diselenide or CIGS photovoltaic cell.

Cadmium Telluride

Cadmium telluride or CdTe is another well-known polycrystalline thin-film material. Similar to copper indium diselenide, CdTe also has a very high absorptivity and can be produced using low-cost techniques. The properties of CdTe can be altered by the addition of alloying elements such as mercury and zinc.

Gallium Arsenide

Gallium arsenide or GaAs is a compound of two elements: gallium and arsenic. Gallium is rarer than gold and is a byproduct of the smelting of other metals, particularly aluminum and zinc. Arsenic, on the other hand, is not rare, however it is poisonous. Gallium arsenide also has a very high absorptivity and it only requires a cell of a few microns thick to absorb sunlight. GaAs cells are unaffected by heat and is highly resistant to damage from radiation. This makes it suitable for concentrator systems and space applications.

Source: AZoCleantech
Last update 30th March 2008

Date Added: Mar 30, 2008
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