ИСТИНА

Chemical sensors based on organic field-effect transistors (OFETs) have attracted considerable attention in the areas of industrial safety control, food spoilage detection and medical diagnostics due to an impressive combination of low limit of detection, low power consumption and portability. However, the OFET-based sensors usually have two main disadvantages – poor air stability and poor restoration at room temperature. In our work[1] we present novel highly sensitive gas sensors based on Langmuir-Schaefer monolayer OFETs prepared from organosilicon derivative of [1]benzothieno[3,2-b][1]-benzothiophene[2]. The devices fabricated are able to operate in air atmosphere and were found to be sensitive to ammonia and hydrogen sulphide at low concentration (down to tens of ppb). Moreover, we demonstrated that direct current response of such sensors can be splitted into the variation of different transistor parameters, which are responsible for the interactions with different toxic gases. The sensor response estimation routine developed allows complete distinguishing of two different gases - ammonia and hydrogen sulphide - with a single sensing device. In addition, the devices investigated are reusable and can be restored to initial characteristics at room temperature. These results open new perspectives for the OFET-based gas-sensing technology. We believe that the approach elaborated can be further extended to other toxic gases enabling the development of a complex air analysis system based on a single device. Preliminary tests of nitrogen oxide sensing with Langmuir-Schaefer monolayer OFETs demonstrated even different transistor parameters behaviour in the presence of this gas at sub-ppm concentrations, that will be a subject of our further investigations. The work was supported by RFBR (project № 17-03-00222) and performed in the framework of leading science school NSh-5698.2018.3. References: [1] A.S. Sizov, A.A. Trul et al. ACS Appl Mater Interfaces, 10(50), 43831–43841(2018). [2] A.A. Trul, A.S. Sizov et al. Journal of Materials Chemistry C 6(36), 9649-9659(2018).