Semiconductor Electrodes: XLI . Improvement of Performance of Electrodes by Electrochemical Polymerization of o‐Phenylenediamine at Surface Imperfections

The dark electrochemical polymerization of o‐phenylenediamine (OPD) at and single crystal electrodes (surface ⊥ C axis exposed) was investigated. The results indicate that polymerization occurs only at surface imperfections (edges, steps) in the otherwise smooth van der Waal's surface. The photoelectrochemical response, in aqueous solutions containing and , of electrodes subjected to this polymerization is improved compared to the untreated electrodes. The results are consistent with a decrease in recombination rate due to blocking of surface states by OPD polymerization. The characteristics of several PEC cells before and after OPD polymerization are also described. Increases in the solar‐to‐electrical power efficiency, η, range from 30–300% after surface pretreatment.