Production of Solar-Grade Silicon by the SiF4 and Mg Reaction
| Autor: | Angel Sanjurjo, Jianer Bao, Xiaobing Xie |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Reaction mechanism
Materials science Silicon Reducing agent Drop (liquid) General Engineering chemistry.chemical_element 02 engineering and technology Raw material 010402 general chemistry 021001 nanoscience & nanotechnology Magnesium silicide 01 natural sciences 0104 chemical sciences law.invention chemistry.chemical_compound chemistry Chemical engineering Impurity law Solar cell 0210 nano-technology |
| Zdroj: | Metallurgical and Materials Transactions E. 3:299-307 |
| ISSN: | 2196-2944 2196-2936 |
| Popis: | Because crystalline Si substrate still accounts for a significant portion of the total cost of solar cells, substantial efforts have been invested in the development of new processes that can significantly lower the production cost of solar-grade silicon. At SRI International, we developed a low-cost process of producing solar-grade silicon based upon the SiF 4 -Na reaction. This process has now been scaled up to pilot-plant level, and solar cells obtained using such silicon feedstock reached > 18% efficiencies. Due to continuing increases in demand and production capacity and the simultaneous drop in price of Mg metal, we decided to explore its potential as a reducing agent instead of Na metal. Experimental conditions for obtaining a fast and complete metallothermic reaction between SiF4 and Mg are identified and aspects of the reaction mechanism are discussed. The reaction involves both a heterogeneous liquid-gas phase reaction and a homogeneous gas-gas phase reaction. The separation of the products, Si and MgF 2 , is described. When pure Mg was used, Si obtained after melt separation had the potential to be suitable for solar cell applications. |
| Databáze: | OpenAIRE |
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