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Title: Unassisted Water Splitting Using a GaSb xP (1- x ) Photoanode

Abstract

Here in this work, unbiased water splitting with 2% solar-to-hydrogen efficiency under AM 1.5 G illumination using new materials based on GaSb 0.03P 0.97 alloy is reported. Freestanding GaSb xP 1-x is grown using halide vapor phase epitaxy. The native conductivity type of the alloy is modified by silicon doping, resulting in an open-circuit potential (OCP) of 750 mV, photocurrents of 7 mA cm -2 at 10 sun illumination, and corrosion resistance in an aqueous acidic environment. Alloying GaP with Sb at 3 at% improves the absorption of high-energy photons above 2.68 eV compared to pure GaP material. Electrochemical Impedance Spectroscopy and illuminated OCP measurements show that the conduction band of GaSb xP 1-x is at -0.55 V versus RHE irrespective of the Sb concentration, while photocurrent spectroscopy indicates that only radiation with photon energies greater than 2.68 eV generate mobile and extractable charges, thus suggesting that the higher-laying conduction bands in the Γ 1 valley of the alloys are responsible for exciton generation.

Authors:
 [1];  [1];  [2];  [2];  [1];  [3];  [4];  [5];  [5];  [6]
  1. Univ. of Louisville, KY (United States). Department of Chemical Engineering
  2. Univ. of Louisville, KY (United States). Conn Center for Renewable Energy Research
  3. Univ. of Louisville, KY (United States). Center for Computational Sciences
  4. Daimler AG, RD/EKB, Ulm (Germany)
  5. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  6. Univ. of Louisville, KY (United States). Department of Chemical Engineering and Conn Center for Renewable Energy Research
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Fuel Cell Technologies Office (EE-3F)
OSTI Identifier:
1426640
Alternate Identifier(s):
OSTI ID: 1422018
Report Number(s):
NREL/JA-5900-70812
Journal ID: ISSN 1614-6832
Grant/Contract Number:  
AC36-08GO28308
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Advanced Energy Materials
Additional Journal Information:
Journal Volume: 8; Journal Issue: 16; Journal ID: ISSN 1614-6832
Publisher:
Wiley
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; bandgap tuning; DFT calculations; HVPE; III-V alloy; water splitting

Citation Formats

Martinez-Garcia, Alejandro, Russell, Harry B., Paxton, William, Ravipati, Srikanth, Calero-Barney, Sonia, Menon, Madhu, Richter, Ernst, Young, James, Deutsch, Todd, and Sunkara, Mahendra K. Unassisted Water Splitting Using a GaSbxP(1-x) Photoanode. United States: N. p., 2018. Web. doi:10.1002/aenm.201703247.
Martinez-Garcia, Alejandro, Russell, Harry B., Paxton, William, Ravipati, Srikanth, Calero-Barney, Sonia, Menon, Madhu, Richter, Ernst, Young, James, Deutsch, Todd, & Sunkara, Mahendra K. Unassisted Water Splitting Using a GaSbxP(1-x) Photoanode. United States. doi:10.1002/aenm.201703247.
Martinez-Garcia, Alejandro, Russell, Harry B., Paxton, William, Ravipati, Srikanth, Calero-Barney, Sonia, Menon, Madhu, Richter, Ernst, Young, James, Deutsch, Todd, and Sunkara, Mahendra K. Wed . "Unassisted Water Splitting Using a GaSbxP(1-x) Photoanode". United States. doi:10.1002/aenm.201703247. https://www.osti.gov/servlets/purl/1426640.
@article{osti_1426640,
title = {Unassisted Water Splitting Using a GaSbxP(1-x) Photoanode},
author = {Martinez-Garcia, Alejandro and Russell, Harry B. and Paxton, William and Ravipati, Srikanth and Calero-Barney, Sonia and Menon, Madhu and Richter, Ernst and Young, James and Deutsch, Todd and Sunkara, Mahendra K.},
abstractNote = {Here in this work, unbiased water splitting with 2% solar-to-hydrogen efficiency under AM 1.5 G illumination using new materials based on GaSb0.03P0.97 alloy is reported. Freestanding GaSbxP1-x is grown using halide vapor phase epitaxy. The native conductivity type of the alloy is modified by silicon doping, resulting in an open-circuit potential (OCP) of 750 mV, photocurrents of 7 mA cm-2 at 10 sun illumination, and corrosion resistance in an aqueous acidic environment. Alloying GaP with Sb at 3 at% improves the absorption of high-energy photons above 2.68 eV compared to pure GaP material. Electrochemical Impedance Spectroscopy and illuminated OCP measurements show that the conduction band of GaSbxP1-x is at -0.55 V versus RHE irrespective of the Sb concentration, while photocurrent spectroscopy indicates that only radiation with photon energies greater than 2.68 eV generate mobile and extractable charges, thus suggesting that the higher-laying conduction bands in the Γ 1 valley of the alloys are responsible for exciton generation.},
doi = {10.1002/aenm.201703247},
journal = {Advanced Energy Materials},
issn = {1614-6832},
number = 16,
volume = 8,
place = {United States},
year = {2018},
month = {2}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 4 works
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Figures / Tables:

Figure 1 Figure 1: HVPE-grown GaSb0.03P0.97 free-standing films a) X-ray diffraction pattern for GaSbxP(1-x) (GaP [PDF 01- 0722146] shown for comparison), b)-c) SEM cross-sectional views

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Works referenced in this record:

Nanoporous BiVO4 Photoanodes with Dual-Layer Oxygen Evolution Catalysts for Solar Water Splitting
journal, February 2014


    Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.