Manufacturing Polycrystalline Silicon

Polycrystalline Silicon

The silicon wafers used to make photovoltaic cells are manufactured with the same element that is a basic component of sand or quartz. After extracting pure silicon from these common materials, the silicon industry has made what is called metallurgical silicon. This silicon is fine for making metal alloys, but it is not yet at the grade necessary for use in electrical components like solar cells. Doing that requires another step — making polycrystalline silicon.

The Polycrystalline Silicon Wafer Process

Using what is called the Siemens process, metallurgical silicon is melted at very high temperatures, releasing silicon-containing vapors. These vapors are then deposited onto rods, creating polycrystalline silicon. This silicon is composed of many smaller silicon crystals of various sizes fused together

To make wafers, polycrystalline silicon is typically melted into a usable shape and then processed to make thin sheets. When used in photovoltaic cells, this form of silicon typically has a blue tint. Creating monocrystalline wafers takes an additional step, creating a finer product, but leading to more expense.

Comparing Monocrystalline versus Polycrystalline Efficiency

SunPower does not use polycrystalline silicon when manufacturing solar panels. Since a single wafer of polycrystalline silicon contains many different crystals of various sizes, travel of electrons released by the photovoltaic effect can be limited. Monocrystalline silicon is without crystal boundaries from end to end, providing free travel throughout the wafer for released electrons, thus generating more electricity. Polycrystalline silicon generally leads to solar cells of 15% efficiency, while SunPower’s monocrystalline silicon leads to solar cells of over 22% efficiency, a very significant difference. That efficiency leads to better electricity production in the same amount of space and in lower levels of light.

Here at Solaron of Sacramento, we only use SunPower solar panels. This lets us always offer our customers the best and most efficient product on the market! For more information on how solar panels made with monocrystalline silicon wafers can benefit you, contact Solaron by telephone or online to arrange a free solar energy consultation.

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