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High Broadband Light Transmission for Solar Fuels Production Using Dielectric Optical Waveguides in TiO₂ Nanocone Arrays

Yalamanchili, Sisir and Verlage, Erik and Cheng, Wen-Hui and Fountaine, Katherine T. and Jahelka, Philip R. and Kempler, Paul A. and Saive, Rebecca and Lewis, Nathan S. and Atwater, Harry A. (2020) High Broadband Light Transmission for Solar Fuels Production Using Dielectric Optical Waveguides in TiO₂ Nanocone Arrays. Nano Letters, 20 (1). pp. 502-508. ISSN 1530-6984. doi:10.1021/acs.nanolett.9b04225.

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We describe the fabrication and use of arrays of TiO₂ nanocones to yield high optical transmission into semiconductor photoelectrodes covered with high surface loadings of light-absorbing electrocatalysts. Covering over 50% of the surface of a light absorber with an array of high-refractive-index TiO₂ nanocones imparted antireflective behavior (< 5% reflectance) to the surface and allowed > 85% transmission of broadband light to the underlying Si, even when thick metal contacts or opaque catalyst coatings were deposited on areas of the light-facing surface that were not directly beneath a nanocone. Three-dimensional full-field electromagnetic simulations for the 400 – 1100 nm spectral range showed that incident broadband illumination couples to multiple waveguide modes in the TiO₂ nanocones, reducing interactions of the light with the metal layer. A proof-of-concept experimental demonstration of light-driven water oxidation was performed using a p⁺n-Si photoanode decorated with an array of TiO₂ nanocones additionally having a Ni catalyst layer electrodeposited onto the areas of the p⁺n-Si surface left uncovered by the TiO₂ nanocones. This photoanode produced a light-limited photocurrent density of ~ 28 mA cm⁻² under 100 mW cm⁻² of simulated Air Mass 1.5 illumination, equivalent to the photocurrent density expected for a bare planar Si surface even though 54% of the front surface of the Si was covered by an ~ 70 nm thick Ni metal layer.

Item Type:Article
Related URLs:
URLURL TypeDescription
Cheng, Wen-Hui0000-0003-3233-4606
Fountaine, Katherine T.0000-0002-0414-8227
Jahelka, Philip R.0000-0002-1460-7933
Kempler, Paul A.0000-0003-3909-1790
Saive, Rebecca0000-0001-7420-9155
Lewis, Nathan S.0000-0001-5245-0538
Atwater, Harry A.0000-0001-9435-0201
Additional Information:© 2019 American Chemical Society. Received: October 12, 2019; Revised: November 29, 2019; Published: December 10, 2019. The fabrication and assessment of photoanodes for the oxygen-evolution reaction was supported through the Office of Science of the U. S. Department of Energy under Award No. DE-SC0004993 for the Joint Center for Artificial Photosynthesis and used facilities of the Kavli Nanoscience Institute at Caltech, a DOE Energy Innovation Hub; the development of simulations was supported by the National Science Foundation under award No. EEC-1041895. Author Contributions: S.Y., E.V., and W.H.C. contributed equally. The authors declare no competing financial interest.
Group:JCAP, Kavli Nanoscience Institute
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0004993
Subject Keywords:dielectric nanocone, broadband transmission, nanophotonic, optoelectronic, photoelectrochemical, photovoltaic
Issue or Number:1
Record Number:CaltechAUTHORS:20191212-105210937
Persistent URL:
Official Citation:High Broadband Light Transmission for Solar Fuels Production Using Dielectric Optical Waveguides in TiO2 Nanocone Arrays. Sisir Yalamanchili, Erik Verlage, Wen-Hui Cheng, Katherine T. Fountaine, Philip R. Jahelka, Paul A. Kempler, Rebecca Saive, Nathan S. Lewis, and Harry A. Atwater. Nano Letters 2020 20 (1), 502-508; DOI: 10.1021/acs.nanolett.9b04225
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:100276
Deposited By: George Porter
Deposited On:16 Dec 2019 16:04
Last Modified:16 Nov 2021 17:52

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