Simple and clear evidence for positive feedback limitation by bipolar behavior during scanning electrochemical microscopy of unbiased conductors

摘要

On the basis of an experimentally validated simple theoreticaludmodel, it is demonstrated unambiguously that when an unbiasedudconductor is probed by a scanning electrochemical tip (scanning electrochemicaludmicroscopy, SECM), it performs as a bipolar electrode. Thoughudalready envisioned in most recent SECM theories, this phenomenon isudgenerally overlooked in SECM experimental investigations. However, as isudshown here, this may alter significantly positive feedback measurementsudwhen the probed conductor is not much larger than the tip