Electrophilic-Attack Doped Organic Field-Effect Transistors for Ultrasensitive and Selective Hydrogen Sulfide...

Doping of organic semiconductors (OSCs) has been developed as an effective means of modulating the density and transfer efficiency of charge carriers; however, realization of effective doping to tailor the chemical sensing performance of OSC-based sensors still remains not explored extensively. In addition, the application of OSCs in chemical sensors is usually limited by the poor stability and low selectivity. Herein, flexible donor-acceptor copolymer-based organic field-effect transistor (OFET) chemical sensors are designed via an electrophilic attack doping strategy. The p-dopant trityl tetrakis(pentafluorophenyl) borate (TrTPFB) can be effectively doped into the host molecular N-alkyl-diketopyrrolo-pyrroledithienylthieno[3,2-b]thiophene (DPPDTT). It is simple to alter the doping efficiency and film thickness (ca. 5.5-17.7 nm) by adjusting the proportion and concentration of guest-host molecules, which endows facile carrier mobility and enhanced sensing sensitivity modulation toward reducing gases at room temperature. Particularly, 1.0 mol% TrTPFB-doped DPPDTT achieved the highest response to H₂S gas, including ultralow detection concentration (0.5 ppb), excellent selectivity, high humidity stability, and long-term storage stability. This work can provide a new strategy for the potential applications of the organic electronic sensing devices.