Detection of H₂O₂ with Hygroscopic Insulator Organic Thin Film Transistor

Abstract Hygroscopic insulator field effect transistors (HIFETs) are a class of solid‐state, low‐voltage organic thin film transistors with promising sensitivity to hydrogen peroxide (H₂O₂). While work has progressed on the development and understanding of HIFET‐based sensors, important questions regarding the fundamental H₂O₂ sensing mechanisms need to be fully investigated. In this work, a detailed study of the effects of H₂O₂ on the transient drain currents and transfer characteristics of HIFETs, while varying analyte concentrations and device voltages, is presented. The sensing mechanism is found to be consistent with the direct oxidation of the organic semiconductor channel, poly(3‐hexylthiophene‐2,5‐diyl), by H₂O₂ diffused into the device through the permeable top gate electrode and hygroscopic insulator. Further, the importance of having a transistor structure in sensing H₂O₂, as compared to a two‐terminal device, is demonstrated. These results represent important progress in the understanding of HIFET‐based sensors, revealing paths for future applications and optimization.