Displacement of the bandedges of GaInP{sub 2} in aqueous electrolytes induced by surface modification

Journal Article · Tue Aug 01 04:00:00 EDT 1995 · Journal of the Electrochemical Society

DOI:https://doi.org/10.1149/1.2050065· OSTI ID:110123

Kocha, S S; Turner, J A ^[1]

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1. National Renewable Energy Lab., Golden, CO (United States). Photoconversion Branch

Photoelectrolysis of water at ambient temperature (25 C) into hydrogen and oxygen thermodynamically requires a free energy of 1.23 eV. GaInP{sub 2} was identified as a promising material since its bandgap (1.8 to 1.9 eV) is ideal for this reaction. However, previous work determining the flatband potential of p-GaInP{sub 2} has revealed that the position of the bandedges are from 100 to 400 meV too negative for water splitting. The surface of epi layer p-GaInP{sub 2} electrodes was treated using 8-quinolinol, cupferron, and ferrocyanide, producing a modified surface directed at varying the Helmholtz layer charge. Mott-Schottky and photocurrent-voltage measurements were carried out to determine if there was any shift in the flatband potential or change in the onset of photocurrent due to the altered surface charge. Treatments with 8-quinolinol and cupferron were found to shift the flatband to more positive potentials; treatments with ferrocyanide produced a negative shift. The quinolate-modified interface had flatband potentials that were pH independent in the range 5 through 8. Photoluminescence studies on electrodes that were etched, treated with 8-quinolinol, and exposed to air for long periods showed no degradation of the luminescence intensity or photoluminescence decay time, in contrast to untreated electrodes.

• Sponsoring Organization: USDOE
• OSTI ID: 110123
• Journal Information: Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 8 Vol. 142; ISSN JESOAN; ISSN 0013-4651
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
14 SOLAR ENERGY
36 MATERIALS SCIENCE
GALLIUM PHOSPHIDES
GRADED BAND GAPS
HYDROGEN PRODUCTION
INDIUM PHOSPHIDES
MATERIALS TESTING
PHOTOCURRENTS
PHOTOELECTROLYSIS
SURFACE POTENTIAL
SURFACE PROPERTIES