Thiadiazole-fused Quinoxalineimide as an Electron-deficient Building Block for N-type Organic Semiconductors

A strong electron-accepting planar π-conjugated framework, thiadiazole-fused quinoxalineimide (TQI), was designed and synthesized. Three TQI-based small molecules exhibit deep lowest-unoccupied molecular orbital (LUMO) levels, which require air stable n-channel conduction (∼−4.0 eV). Among these molecules, Hex-TQI-Br exhibits air-stable n-channel charge transport with a moderate mobility of 0.044 cm2 V–1 s–1.