High-Performance Organic Field-effect Transistor and H2S Sensors Based on Indolo[3,2-b]carbazole Derivatives with Contorted Configuration

In order to investigate the effects of molecular configuration and noncovalent bonding forces on the properties of organic field-effect transistors (OFET) and sensors, two novel indolo[3,2-b]carbazole (ICZ) derivatives 6,12-bis(benzo[b]furan-2-yl)-indolecarbazole (ICZ-BF) and 6,12-bis(benzo[b]thiophen-2-yl)-indolecarbazole (ICZ-BT) with contorted configuration were synthesized and characterized. The simulation calculation indicates that the introduction of hydrogen bonds is beneficial for reducing the distortion of molecular configuration and enhancing the binding energy with the detected H₂S molecule. The single crystal XRD further reveals that the weak noncovalent bonding forces such as intramolecular and intermolecular hydrogen bonds as well as π-π stacking can effectively alter the molecular configuration and aggregation state. The OFET based on ICZ derivative was prepared and the mobility of ICZ-BF was 0.0294 cm²V⁻¹s⁻¹, while no FET performance was observed for ICZ-BT. The OFET based on ICZ-BF were further used as gas sensor to detect H₂S and exhibited excellent sensing response and selectivity with the drain current change rate of 5.4% and the relative sensitivity (RS) of 540% ppm^-1 when the gas concentration lower to 10 ppb level.