Deuteration of ion-in-conjugation materials for improved sensitivity with maintained response/recovery ability

Organic chemiresistors have been widely investigated in recent years due to their high sensitivity and excellent robustness (time-stability, compatibility, selectivity, and batch-to-batch reproductivity). However, in the pursuit of high sensitivity, compromising the response and recovery ability of these chemiresistors were often inevitable. Here, we propose an unperceived method to enhance the sensitivity of ion-in-conjugation (IIC) materials through the isotope effect, achieved by partial deuteration of the interaction sites. The fabricated sensor after deuteration achieves about four-fold enhancement of sensitivity at the parts-per-billion (ppb) level in detecting trace nitric dioxide (NO₂), while maintains its response/recovery ability. Linear fittings of the extracted sensitivity denote that the deuteration does not alter the adsorption models. Combining the theoretical calculation and the measurements with in-situ infrared spectroscopy and the resonant microcantilever (RMC), the interaction site of the dual hydrogen bonding (DHB) is proven. This strategy highlights that the effectiveness of isotope effect on improving the sensory performances in chemiresisitors and may expand more applications to other semiconductor devices.