Modeling carrier density of organic mixed ionic–electronic conductors in aqueous solutions using spectroelectrochemical measurement

Abstract Charge carrier density is essential for organic mixed ionic–electronic conductors (OMIECs) operating in aqueous environments. However, traditional methods for measuring this property are limited. This study introduces a novel approach using spectroelectrochemistry to evaluate charge carrier density in OMIECs immersed in aqueous solutions. By incorporating (3‐glycidyloxypropyl)trimethoxysilane (GOPS) into PEDOT:PSS films, carrier density can be systematically control. A detailed explanation of the spectroelectrochemical setup is provided and an analytical model is developed that accurately predicts the relationship between GOPS concentration and charge carrier density. The findings demonstrate the effectiveness of spectroelectrochemistry as a tool for measuring charge carrier density in OMIECs, paving the way for further advancements in understanding and optimizing their performance in aqueous solutions.