Microscale Electrochemical Cell on a Custom CMOS Transimpedance Amplifier for High Temporal Resolution Single Entity Electrochemistry**

Abstract

Abstract Stochastic collision electrochemistry requires high‐resolution and high‐bandwidth current amplification due to the low magnitude and short duration of the current signals. However, increasing the current amplifier bandwidth leads to increased current noise levels, which in turn obscures the current signal generated from stochastic collision electrochemistry experiments. The key to minimizing current noise is an experimental configuration that minimizes the input capacitance to the current amplifier. Here, we report a new strategy to minimize the input capacitance to a current amplifier by using a movable microscale electrochemical cell, formed at the end of a micropipette using a scanning electrochemical cell microscopy approach, to conduct electrochemical experiments in close proximity (∼300 μm) to a transimpedance amplifier. We demonstrated this via electro‐oxidation of single Ag nanoparticles detected at a bandwidth of 1 MHz.