Methylviologen Redox Reactions at Semiconductor Single Crystal Electrodes

Article abstract of DOI:10.1002/bbpc.19961000712

The mechanism of the two-step reduction of the rnethylviologen cation radical (MV²⁺) was studied at CdS, GaAs and InP single crystal electrodes. In aqueous solution the second step (MV^+?→MV⁰) gives rise to layer formation \vhich is not observed in mixed ethanol/water solutions. This layer has interesting electrical properties. The reoxidation of MV⁰ occurs by electron injection into the conduction band of aii three semiconductors. The reoxidation of MV^+? at InP is also a conduction band reaction and electroluminescence is observed with the ptype semiconductor. Electron injection from MV^+dot; into the conduction band of GaAs is not observed while the kinetics of the reaction at CdS depend critically on the state of the electrode surface and on the nature of the electrolyte solution. ? VCH Verlagsgesellschaft mbH,.