Highly sensitive detection of gallic acid based on organic electrochemical transistors with poly(diallyldimethylammonium chloride) and carbon nanomaterials nanocomposites functionalized gate electrodes

We report the development of gallic acid sensors using organic electrochemical transistors (OECTs) based on poly(3,4-ethylenedioxythiophene): poly(styrene sulfonic acid) (PEDOT:PSS) for the first time. The device performance was optimized by functionalizing the gate electrodes of the OECTs with nanocomposites of poly(diallyldimethylammonium chloride) (PDDA) and multiple carbon nanomaterials. The detection limit of the optimized OECT sensor was identified to be as low as 10 nM of GA. We also demonstrated that the optimized OECT sensor worked with a high recovery for rapid and accurate assessment of total phenol content of practical tea samples. Since the OECT is based on the oxidation-reduction reaction at the gate electrode of target analytes, we believe our low-cost and easy-fabricating OECT-based sensor offers a promising platform for the development of disposable and portable sensors with high sensitivity for a wide range of practical samples.