Monolayer organic field effect transistors (OFETs) provide opportunity for ultrahigh sensitivity gas sensor applications due to a strong dependence of OFET key parameters on the environment. However, an impressive combination of both high sensitivity and instantaneous response of such gas sensors can be achieved only on low-defect dense monolayers with high electrical performance. Herein, we investigated monolayer thin film formation of recently developed benzothieno[3,2-b][1]benzothiophene (BTBT) organosilicon dimer D2-Und-BTBT-Hex by Langmuir–Blodgett, Langmuir–Schaefer and spin-coating methods. For all these techniques, the conditions of uniform low-defect monolayer formation were found. These monolayers were used for preparation of OFET devices, which demonstrated excellent electrical performance with a hole mobility up to 7 × 10⁻² cm² V⁻¹ s⁻¹, a threshold voltage around 0 V and an on–off ratio of 10⁵ as well as long-term stability of half-year storage under ambient conditions. Preliminary investigations demonstrated that the monolayer OFETs give an instantaneous response to ammonia at low concentrations (down to 400 ppb). These findings show a great potential of BTBT-based OFETs for large-area sensing device application.

Determination of food freshness, which is the most ancient role of the human sense of smell, is still a challenge for compact and inexpensive electronic nose devices. Fast, sensitive, and reusable sensors are long-awaited in the food industry to replace slow, labor-intensive, and expensive bacteriological methods. In this work, we present microbiological verification of a novel approach to food quality monitoring and spoilage detection using an electronic nose based on organic field-effect transistors (OFETs) and its application for distinguishing products. The compact device presented is able to detect spoilage-related gases as early as at the 4 × 10⁴ CFU g^-1 bacteria count level, which is 2 orders of magnitude below the safe consumption threshold. Cross-selective sensor array based on OFETs with metalloporphyrin receptors were made on a single substrate using solution processing leading to a low production cost. Moreover, machine learning methods applied to the sensor array response allowed us to compare spoilage profiles and separate them by the type of food: pork, chicken, fish, or milk. The approach presented can be used to monitor food spoilage and distinguish different products with an affordable and portable device.

Elaboration of biosensors on the base of organic transistors with embedded biomolecules which can operate in an aqueous environment is of paramount importance. Electrolyte-gated organic field-effect transistors demonstrate high sensitivity in detection of various analytes. In this paper, we demonstrated the possibility of quantitative fast specific determination of virus particles by an aptasensor based on EGOFET. The sensitivity and selectivity of the devices were examined with the influenza A virus as well as with control bioliquids like influenza B, Newcastle disease viruses or allantoic fluid with different dilutions. The influence of the semiconducting layer thickness on EGOFETs sensory properties is discussed. The fabrication of a multi-flow cell that simultaneously registers the responses from several devices on the same substrate and the creation of a multi-sensor flow device are reported. The responses of the elaborated bioelectronic platform to the influenza A virus obtained with application of the portable multi-flow mode are well correlated with the responses obtained in the laboratory stationary mode.