# Control Circuits for Potentiostatic/Galvanostatic Polarization and Simultaneous Chemical Sensing by a Light-Addressable Potentiometric Sensor

## TL;DR

This paper introduces a new four-electrode system combining a LAPS sensor with electrochemical measurements to study chemical processes and ion distribution simultaneously.

## Contribution

The novel integration of a LAPS sensor into a four-electrode system enables simultaneous electrochemical polarization and potentiometric sensing.

## Key findings

- A four-electrode system was designed to allow potentiostatic/galvanostatic polarization and LAPS measurement simultaneously.
- Different grounding modes were tested to evaluate their functionality and interference in the integrated system.
- The system is suitable for analyzing dynamic electrochemical processes and ion distribution in real-time.

## Abstract

A light-addressable potentiometric sensor (LAPS) is a semiconductor-based sensor platform for sensing and imaging of various chemical species. Being a potentiometric sensor, no faradaic current flows through its sensing surface, and no electrochemical reaction takes place in the course of LAPS measurement. In this study, a four-electrode system is proposed, in which a LAPS is combined with the conventional three-electrode electrochemical system. A LAPS is included as the fourth electrode for potentiometric sensing and imaging of the target analyte in the course of an electrochemical reaction taking place on the surface of the working electrode. The integrated system will be useful for analyzing dynamic processes, where both the electrochemical process on the electrode surface and the ion distribution in the solution need to be simultaneously investigated. Different grounding modes of control circuits that can simultaneously conduct potentiostatic/galvanostatic polarization and LAPS measurement are designed, and their functionalities are tested. The interference between polarization and LAPS measurement will also be discussed.