Diketopyrrolopyrrole-based polymer transistors for hazardous volatile organic compound detection

Here, we report on highly sensitive OTFT sensors based on ultrathin poly[[2,5-bis(2-octyldodecyl)-2,3,5,6-tetrahydro-3,6-dioxopyrrolo[3,4-c]pyrrole-1,4-diyl]-alt-[[2,2′-(2,5-thiophene)bis-thieno(3,2-b)thiophene]-5,5′-diyl]] (DPPT-TT) organic thin film transistors (OTFTs) for detection of volatile organic compounds (VOCs). The flexible ultrathin DPPT-TT-OTFT sensors show high sensitivity of ∼87% in the exposed ammonia compared to ethanol and ethylene gases, which is ascribed to severe hole trapping in the semiconducting channel. Additionally, the gas sensor exhibit intense alteration of the OTFT performance parameters, including turn-on voltage, threshold voltage, and on and off current to common VOCs, such as 2-propanol, trichloroethylene, and 1,2-dichloroethane. In particular high sensitivity with good reversibility is achieved in the exposed 2-propanol.This work demonstrates that OTFTs with the dye-based conjugated polymers have great potential to realize real-time monitoring of various hazardous VOCs.