PLoS ONE (Jan 2014)

Preparation of high purity crystalline silicon by electro-catalytic reduction of sodium hexafluorosilicate with sodium below 180 °C.

  • Yuan Chen,
  • Yang Liu,
  • Xin Wang,
  • Kai Li,
  • Pu Chen

DOI
https://doi.org/10.1371/journal.pone.0105537
Journal volume & issue
Vol. 9, no. 8
p. e105537

Abstract

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The growing field of silicon solar cells requires a substantial reduction in the cost of semiconductor grade silicon, which has been mainly produced by the rod-based Siemens method. Because silicon can react with almost all of the elements and form a number of alloys at high temperatures, it is highly desired to obtain high purity crystalline silicon at relatively low temperatures through low cost process. Here we report a fast, complete and inexpensive reduction method for converting sodium hexafluorosilicate into silicon at a relatively low reaction temperature (∼ 200 °C). This temperature could be further decreased to less than 180 °C in combination with an electrochemical approach. The residue sodium fluoride is dissolved away by pure water and hydrochloric acid solution in later purifying processes below 15 °C. High purity silicon in particle form can be obtained. The relative simplicity of this method might lead to a low cost process in producing high purity silicon.