Methylviologen redox reactions at semiconductor single crystal electrodes

Schoenmakers, G. H.; Waagenaar, R.; Kelly, John J.

doi:10.1002/bbpc.19961000712

Cited by 13 publications

(8 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Electron Capture: n-GaAs/MV 2+ . As reported by Schoenmakers et al, methylviologen, dissolved as MV 2+ , is reduced by electron capture at the n-CdS electrode. Furthermore, these authors showed that in a H 2 O−C 2 H 5 OH (1:1) mixture, the final reaction product MV 0 is not absorbed at the CdS surface, in contrast to the behavior in aqueous solutions.…”

Section: Resultsmentioning

confidence: 51%

On the Diffusion Impedance at Semiconductor Electrodes

Hens

Gomes

1997

J. Phys. Chem. B

View full text Add to dashboard Cite

It is well known that at metal electrodes, mass transport limitations introduce a Warburg impedance in the electrochemical impedance of an electrode process. Semiconductor electrodes, however, react differently from metal electrodes to variations of the applied potential, so that the influence of diffusion on the electrochemical impedance is less straightforward. In this paper, we propose a general approach of this problem, allowing to describe both the metal and semiconductor electrode behavior by using appropriate kinetical models. When discussing the diffusion impedance at ideal semiconductor/electrolyte contacts, distinction must be made between direct capture reactions and direct injection reactions. Whereas the former result in a Randles-like equivalent circuit, no Warburg component is present in the impedance spectrum of the latter if the reverse reaction is negligible. Thus, the electrochemical impedance provides a clear distinction between both reaction types. At nonideal semiconductor/electrolyte contacts, the situation is different because of the unpinning of the band edges. This may result in a Warburg impedance appearing in the electrochemical impedance of an injection reaction as well, i.e. if the shift of the band edges influences the rate constant of the injection reaction.

show abstract

Section: Resultsmentioning

confidence: 51%

On the Diffusion Impedance at Semiconductor Electrodes

Hens

Gomes

1997

J. Phys. Chem. B

View full text Add to dashboard Cite

show abstract

“…The MV 2ϩ /MV •ϩ /MV 0 reduction and oxidation kinetics have been studied on single crystalline CdS and Si electrodes, and in porous Si. 21,22 The MV 2ϩ /MV oϩ couple has a redox potential of Ϫ0.69 V vs. SCE. 23 The MV •ϩ radical cation, which is formed upon reduction of MV 2ϩ can be further reduced to MV 0 ; redox potentials of Ϫ1.1 to Ϫ1.3 V are reported for the MV •ϩ /MV 0 couple.…”

Section: Resultsmentioning

confidence: 99%

“…This suggests that part of the MV 0 layer is removed in the dark. Chemical dissolution of MV 0 is known to occur in aqueous solutions, very likely due to a conproportionation reaction 21 MV 0 (s) ϩ MV 2ϩ r 2MV ϩ…”

Section: Resultsmentioning

confidence: 99%

Photoelectrochemistry of Electrodeposited Cu[sub 2]O

Jongh¹,

Vanmaekelbergh²,

Kelly³

2000

J. Electrochem. Soc.

256

172

View full text Add to dashboard Cite

The photoelectrochemical properties of electrodeposited Cu 2 O in aqueous solutions were investigated. The material showed long term stability under illumination at negative potentials. The diffusion length of electrons in the as-deposited material was of the order of 10-100 nm. We did not observe photocathodic reduction of water. The efficiencies for the reduction of oxygen and the methylviologen cation at these electrodes were surprisingly high. This suggests that, in conjunction with a suitable redox system, electrodeposited Cu 2 O could be a promising material as a p-type photoelectrode in an electrochemical photovoltaic cell.

show abstract

“…In addition, the approximate photovoltage in Figure 6 is less than the maximum photovoltage attainable with crystalline GaP, even though the valence band edge is approximately 1.5 V more positive than the standard potential for MV 2+/+ . 45,52 Finally, the apparent shapes (i.e., "fill factors") of the photoresponses in Figure 6 were not purely rectangular. These cumulative observations are consistent with material electronic properties (e.g., mobility of the minority carrier) that could stand further improvement.…”

Section: ■ Discussionmentioning

confidence: 98%

Macroporous p-GaP Photocathodes Prepared by Anodic Etching and Atomic Layer Deposition Doping

Lee

Bielinski

Fahrenkrug

et al. 2016

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

P-type macroporous gallium phosphide (GaP) photoelectrodes have been prepared by anodic etching of an undoped, intrinsically n-type GaP(100) wafer and followed by drive-in doping with Zn from conformal ZnO films prepared by atomic layer deposition (ALD). Specifically, 30 nm ALD ZnO films were coated on GaP macroporous films and then annealed at T = 650 °C for various times to diffuse Zn in GaP. Under 100 mW cm(-2) white light illumination, the resulting Zn-doped macroporous GaP consistently exhibit strong cathodic photocurrent when measured in aqueous electrolyte containing methyl viologen. Wavelength-dependent photoresponse measurements of the Zn-doped macroporous GaP revealed enhanced collection efficiency at wavelengths longer than 460 nm, indicating that the ALD doping step rendered the entire material p-type and imparted the ability to sustain a strong internal electric field that preferentially drove photogenerated electrons to the GaP/electrolyte interface. Collectively, this work presents a doping strategy with a potentially high degree of controllability for high-aspect ratio III-V materials, where the ZnO ALD film is a practical dopant source for Zn.

show abstract

Methylviologen redox reactions at semiconductor single crystal electrodes

Cited by 13 publications

References 30 publications

On the Diffusion Impedance at Semiconductor Electrodes

On the Diffusion Impedance at Semiconductor Electrodes

Photoelectrochemistry of Electrodeposited Cu[sub 2]O

Macroporous p-GaP Photocathodes Prepared by Anodic Etching and Atomic Layer Deposition Doping

Contact Info

Product

Resources

About