Review - Recent Advancements in the Utilization of Indium Tin Oxide (ITO) in Electroanalysis without Surface Modification

Indium tin oxide (ITO), as an electrode, has superiority over metal electrodes commonly used for electroanalysis due to its low cost, low electrochemical background response, wide working potential window, easy surface functionalization and commercial availability. However, researchers have often modified its surface with electron mediators/electrocatalysts to improve its electrocatalytic properties. The modification of the ITO surface with electron mediators/electrocatalysts is tedious, time consuming, and expensive and often suffers from reproducibility problems. As an alternative to this modification step, scientists have tried to develop different strategies to utilize ITO without modification by electron mediators/electrocatalysts. The suitability of bare ITO electrodes i) to obtain potential electrochemical responses from some electroactive species with high signal to noise (S/N) ratios and ii) to possibly improve the S/N ratio with additional signal amplifying systems make it a very lucrative tool for electrochemists. To promote its advancement, it is of great significance to summarize the recent advances and to highlight its excellence in electroanalysis. Thus, this review summarizes literature published up to 2019, focusing specifically on self-electrocatalytic properties of ITO toward suitable electroactive molecules and signal amplification strategies from bare/electroinactive-binder-modified ITO platforms and evaluating their performance in electrochemical sensing. In addition, the review outlines the scope for further research in this context.