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Energy-Conversion Properties of Vapor-Liquid-Solid–Grown Silicon Wire-Array Photocathodes

Boettcher, Shannon W. and Spurgeon, Joshua M. and Putnam, Morgan C. and Warren, Emily L. and Turner-Evans, Daniel B. and Kelzenberg, Michael D. and Maiolo, James R. and Atwater, Harry A. and Lewis, Nathan S. (2010) Energy-Conversion Properties of Vapor-Liquid-Solid–Grown Silicon Wire-Array Photocathodes. Science, 327 (5962). pp. 185-187. ISSN 0036-8075. doi:10.1126/science.1180783.

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Silicon wire arrays, though attractive materials for use in photovoltaics and as photocathodes for hydrogen generation, have to date exhibited poor performance. Using a copper-catalyzed, vapor-liquid-solid–growth process, SiCl_4 and BCl_3 were used to grow ordered arrays of crystalline p-type silicon (p-Si) microwires on p^+-Si(111) substrates. When these wire arrays were used as photocathodes in contact with an aqueous methyl viologen^(2+/+) electrolyte, energy-conversion efficiencies of up to 3% were observed for monochromatic 808-nanometer light at fluxes comparable to solar illumination, despite an external quantum yield at short circuit of only 0.2. Internal quantum yields were at least 0.7, demonstrating that the measured photocurrents were limited by light absorption in the wire arrays, which filled only 4% of the incident optical plane in our test devices. The inherent performance of these wires thus conceptually allows the development of efficient photovoltaic and photoelectrochemical energy-conversion devices based on a radial junction platform.

Item Type:Article
Related URLs:
URLURL TypeDescription
Boettcher, Shannon W.0000-0001-8971-9123
Spurgeon, Joshua M.0000-0002-2987-0865
Warren, Emily L.0000-0001-8568-7881
Kelzenberg, Michael D.0000-0002-6249-2827
Atwater, Harry A.0000-0001-9435-0201
Lewis, Nathan S.0000-0001-5245-0538
Additional Information:© 2010 American Association for the Advancement of Science. Submitted 19 August 2009; accepted 10 November 2009. We acknowledge the Stanford Global Climate and Energy Project and the U.S. Department of Energy (grant DE-FG02-05ER15754) for financial support. S.W.B. thanks the Kavli Nanoscience Institute for a postdoctoral fellowship. L. O’Leary is thanked for her contributions. The authors have filed U.S. patent applications (20090020150 and 20090020853) related to this work.
Group:Kavli Nanoscience Institute
Funding AgencyGrant Number
Stanford Global Climate and Energy Project (GCEP)UNSPECIFIED
Department of Energy (DOE)DE-FG02-05ER15754
Kavli Nanoscience InstituteUNSPECIFIED
Issue or Number:5962
Record Number:CaltechAUTHORS:20100129-084339516
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:17347
Deposited By: Tony Diaz
Deposited On:01 Feb 2010 02:46
Last Modified:08 Nov 2021 23:34

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