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Silicon for Solar Cells – Highly Purified Polysilicon Refined from Silicon Metal

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Silicon for Solar Cells that are used to make the normal crystalline solar panels is known as Polysilicon.This is a highly purified form of the Silicon Metal that is mined.Note Polysilicon is made through chemical processes which help in purifying the raw silicon and removing the impurities.The Silicon that is used to make Silicon Cells is also used to make semiconductor wafers which is the raw material for the Electronic Industry.Solar Cells require slightly lower purity of 6N compared to the higher 9N required by the Semiconductor Industry.Once Polysilicon is produced it has to be made into flat wafers which require further industrial processes like pouring the metal in crucible to make ingots (Czochralski Process)and then cutting the ingots by wiresaws to make solar wafers.The solar wafers are then converted into solar cells by processes like diffusion,etching etc.

Types of Silicon Cells and Polysilicon Producers

Note solar cells made from a single crystal of silicon are known as monocrystalline solar cells while others are known as multicrystalline solar cells.The efficiency of the 2 types of silicon solar cells differs as does the cost.Most of the world’s major solar energy companies use c-Si Technology in making solar panels.Polysilicon is an energy intensive process which requires cheap electricity.The polysilicon is produced mostly in the western countries like Japan,USA and Germany now.However the rise of solar panel producers in Asia has given rise to large volume Asian producers of polysilicon as well.Note Polysilicon production is concentrated in the hands of 8 companies unlike solar panel production which is done by hundreds of companies.This is a capital intensive process and requires around 2 years to complete a single plant.Here is a list of major polysilicon companies.

Polysilicon Price Boom and Bust

The Solar Crystalline Silicon Industry accounts for almost 85-90% of all the Solar Energy Capacity installed globally and is growing at a rapid rate.Polysilicon which is the main raw material for the industry has been the focus of the industry over the last 2-3 years.The reason was the sharp run up in Poly Prices in 2008 to $400/kg despite costing just $30/kg.The rapid increase in the Solar Module Industry had caught the poly producers by surprise as it normally takes 2-3 years for a Poly Plant to come online.This had led downstream producers with a secure cheap supply of polysilicon as the kings of the market.New Business Models  based on low or no polysilicon usage were invested in.However the 2009 Crash brought down the price to $50/kg killing many of the companies.Polysilicon prices are expected to come down in the future as more polysilicon plants are built to meet the massively growing demand for Silicon Cells.


Abhishek Shah

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