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Electrodeposition of nanocrystalline silicon onto graphite-based materials from molten fluoride mixtures
|Liliia Molotovska , Dmytro Shakhnin , Malyshev Victor|
Institute of General and Inorganic Chemistry (IGICH), 32/34 Palladin Ave., Kyiv 03142, Ukraine
Crystalline silicon is one of the most perspective materials for terrestrial solar cells, and results of further investigations concerning its obtaining methods should be associated with its cost reduction.
Production of solar cell using LiF-KF-K2SiF6 fluoride melts is very attractive and perspective in terms of silicon obtaining with desired purity level.
Silicon coating deposition onto low-cost electrically conducting substrates such as steel, brass, nickel, tungsten, or graphite is very promising in terms of solar cells cost reduction. Unfortunately, for most of these substrates, silicides formation is typical at 1023 K. Therefore, graphite is the most perspective material due to its lowest reactivity.
The objective of the present study was to electrodeposit high purity silicon onto graphite substrate in the form of adherent coating and to study the deposits morphology dependence on the electrodeposition conditions.
Dense, good adherent silicon coating was deposited onto graphite base at potentials -0,75 ± 0,05 V vs. Ag or Pt electrode from molten LiF-KF-K2SiF6 system at 1023 K. Silicon containing compound concentration was within 8-14 mol. % range. Cross-sections of sediments indicate nodular or dendritic growth up to several millimeters at the main part of adherent layer up to 1.0 mm thick. Polycrystalline silicon has columnar structure with grain size of about 250 nm. Impurities (Cu, Fe, and Ni) content did not exceed 0.005%. Specific resistance of deposit at room temperature was always higher than 1 Ω·cm.The effect of electrodeposition parameters on the morphology of the silicon surface and the possibility to use polycrystalline silicon in solar cells were discussed.
Presentation: Poster at Nano and Advanced Materials Workshop and Fair, by Liliia Molotovska
See On-line Journal of Nano and Advanced Materials Workshop and Fair
Submitted: 2013-07-17 22:28 Revised: 2013-07-17 22:59