CaltechAUTHORS
  A Caltech Library Service

An analysis of the optimal band gaps of light absorbers in integrated tandem photoelectrochemical water-splitting systems

Hu, Shu and Xiang, Chengxiang and Haussener, Sophia and Berger, Alan D. and Lewis, Nathan S. (2013) An analysis of the optimal band gaps of light absorbers in integrated tandem photoelectrochemical water-splitting systems. Energy and Environmental Science, 6 (10). pp. 2984-2993. ISSN 1754-5692. https://resolver.caltech.edu/CaltechAUTHORS:20131118-152050309

[img]
Preview
PDF - Published Version
See Usage Policy.

984Kb
[img]
Preview
PDF - Supplemental Material
See Usage Policy.

268Kb

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20131118-152050309

Abstract

The solar-to-hydrogen (STH) efficiency limits, along with the maximum efficiency values and the corresponding optimal band gap combinations, have been evaluated for various combinations of light absorbers arranged in a tandem configuration in realistic, operational water-splitting prototypes. To perform the evaluation, a current–voltage model was employed, with the light absorbers, electrocatalysts, solution electrolyte, and membranes coupled in series, and with the directions of optical absorption, carrier transport, electron transfer and ionic transport in parallel. The current density vs. voltage characteristics of the light absorbers were determined by detailed-balance calculations that accounted for the Shockley–Queisser limit on the photovoltage of each absorber. The maximum STH efficiency for an integrated photoelectrochemical system was found to be ~31.1% at 1 Sun (=1 kW m⁻², air mass 1.5), fundamentally limited by a matching photocurrent density of 25.3 mA cm⁻² produced by the light absorbers. Choices of electrocatalysts, as well as the fill factors of the light absorbers and the Ohmic resistance of the solution electrolyte also play key roles in determining the maximum STH efficiency and the corresponding optimal tandem band gap combination. Pairing 1.6–1.8 eV band gap semiconductors with Si in a tandem structure produces promising light absorbers for water splitting, with theoretical STH efficiency limits of >25%.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1039/c3ee40453fDOIArticle
http://pubs.rsc.org/en/Content/ArticleLanding/2013/EE/c3ee40453fPublisherArticle
ORCID:
AuthorORCID
Hu, Shu0000-0002-5041-0169
Xiang, Chengxiang0000-0002-1698-6754
Haussener, Sophia0000-0002-3044-1662
Lewis, Nathan S.0000-0001-5245-0538
Additional Information:© 2013 Royal Society of Chemistry. Received 7th February 2013; Accepted 11th April 2013; Published online 10th May 2013. This work was supported through the Office of Science of the U.S. Department of Energy under Award no. DE-SC0004993 to the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub.
Group:JCAP
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0004993
Issue or Number:10
Record Number:CaltechAUTHORS:20131118-152050309
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20131118-152050309
Official Citation:Hu, S., C. Xiang, et al. (2013). "An analysis of the optimal band gaps of light absorbers in integrated tandem photoelectrochemical water-splitting systems." Energy & Environmental Science 6(10): 2984-2993.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42538
Collection:CaltechAUTHORS
Deposited By: David McCaslin
Deposited On:19 Nov 2013 15:36
Last Modified:09 Mar 2020 13:18

Repository Staff Only: item control page