(Invited) Self-Assembling Organic Semiconductors for Chemical Sensing

Abstract

Self-assembling monolayers of organic semiconductors are promising for monolayer organic field-effect transistors (OFETs) and various devices based on them, in particular low power consumption integrated circuits and ultrasensitive gas sensors [1]. Recently we have developed highly stable organosilicon derivatives of organic semiconductor benzothieno[3,2-b][1]benzothiophene (BTBT) capable to self-assembly into a monolayer semiconducting film by Langmuir–Blodgett, Langmuir–Schaefer (LS) or spin-coating methods [2,3]. These monolayer films 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. They were successfully utilized for multiparamertic real time detection of NH3 and H2S in dry air [4]. Modified by additional metal-containing porphyrin receptor layer, two-layer OFETs were investigated as ultrasensitive gas sensors for NH3 and H2S real-time detection in the humid air [5]. Introduction of the receptor layers on top of the LS semiconducting monolayer provides the device sensitivity enhancement as well as allows tuning the sensor selectivity. They demonstrated the improvement of both the limit of detection (down to ca. 60−70 ppb) and sensitivity in the air with relative humidity up to 60 %. Impressive combination of the sensor high sensitivity and reproducibility with fast response and full recovery after finishing the analyte exposure enables utilizing the fabricated two-layer OFETs as chemo-sensors in real gas analyzing systems environmental pollutions control. This work was supported by the Russian Science Foundation (grant 19-73-30028).