Chemically derivatized n-type semiconducting gallium arsenide photoelectrodes. Thermodynamically uphill oxidation of surface-attached ferrocene centers
n-type semiconducting GaAs surfaces can be derivatized using (1,1'-ferrocenediyl)dichlorosilane (1), resulting in surface-attached, electroactive, ferrocene centers. Coverage of electroactive material significantly exceeds monolayer coverage in most experiments. The surface-attached ferrocene material can be oxidized in an uphill sense by irradiating the surface with light of energy greater than 1.4 eV, the band gap of GaAs. Ferrocene can be photooxidized to 50% conversion at a poential of approx. -0.25 V vs. SCE, whereas the 50% conversion occurs at a potential of +0.40 V at a reversible electrode. The ferrocene, then, can be driven uphill by greater than 0.6 V. Surface-attached, photogenerated ferricenium can in turn oxidize solution reductants such as ferrocene itself, I/sup -/, or N,N,N',N'-tetramethyl-p-phenylenediamine as determined by cyclic voltammetry in CH/sub 3/CN/0.1 M (n-Bu/sub 4/N)ClO/sub 4/ solutions. Derivatized electrodes are fairly rugged and result in modestly improved optical to electrical energy conversion compared to a naked GaAs photoelectrode-based cell employing a CH/sub 3/CN/0.1 M (n-Bu/sub 4/N)ClO/sub 4/ solution of ferrocene and ferricenium. 5 figures, 1 table.
- Research Organization:
- Massachusetts Inst. of Technology, Cambridge
- OSTI ID:
- 5624364
- Journal Information:
- J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Journal Issue: 21 Vol. 101:21; ISSN JACSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
140505* -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500 -- Photochemistry
ANODES
ARSENIC COMPOUNDS
ARSENIDES
CHEMICAL REACTIONS
COMPLEXES
CONVERSION
DIENES
DIRECT ENERGY CONVERTERS
ELECTROCHEMICAL CELLS
ELECTRODES
ENERGY CONVERSION
FERROCENE
GALLIUM ARSENIDE SOLAR CELLS
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
HYDROCARBONS
IRON COMPLEXES
JUNCTIONS
ORGANIC COMPOUNDS
OXIDATION
PHOTOANODES
PHOTOELECTRIC CELLS
PHOTOELECTROCHEMICAL CELLS
PHOTOVOLTAIC CELLS
PNICTIDES
POLYENES
SEMICONDUCTOR JUNCTIONS
SOLAR CELLS
SOLAR ENERGY CONVERSION
SURFACES
TRANSITION ELEMENT COMPLEXES