Ultrathin organic crystalline FET sensor based on high-capacitance hydrophobic nanocellulose insulating layer for real-time on-site detection of volatile basic nitrogen.

Real-time and rapid detection of volatile basic nitrogen (VBN) plays a crucial role in ensuring food quality and facilitating the intelligent transformation of the food industry. Herein, hydrophobic surface modification of nanocellulose film is employed to regulate its surface energy and reduce moisture sensitivity. This interface engineering facilitates the growth of ultrathin organic semiconductor crystals, which maximizes the interaction between the electron-donating VBN molecules and the conducting channel to efficiently modulate the charge density. Thus organic field effect transistor (OFETs) sensors constructed on this basis demonstrate ultrahigh sensitivity (1.7 ppt) and instantaneous response for VBN. Furthermore, the devices' sensing performances exhibit no obvious degradation under bending conditions, confirming their excellent flexibility and on-site detection capability. This work provides a new paradigm for food quality monitoring.