Solution-processable small molecules for bulk heterojunction ambipolar thin-film transistors and complementary-like inverters

Abstract Solution-processable thioalkylated bithiophene derivatives with different lengths of side chains ( SBT-n ; n  =  10 , 12 , 14 , 16 , 18 ) have been synthesized and characterized as p-channel organic semiconductors for thin-film transistors (TFTs). Based on a combination of the highest performing SBT derivative ( SBT-14 ) and quinoidals ( DTTRQ s) as p- and n-channel materials, solution-processed small-molecular bulk heterojunction (BHJ) ambipolar thin-film transistors were fabricated, and the resulting devices showed air-stable and high ambipolar performance with well-balanced electron and hole mobilities as high as 0.70 cm 2  V −1  s −1 and 0.21 cm 2  V −1  s −1 , respectively. Furthermore, complementary-like inverters comprising two ambipolar thin-film transistors were demonstrated, which exhibited a high voltage gain of up to 81. Our study clearly demonstrated that side chain engineering of small molecular organic semiconductors had a significant influence on the electrical performance of TFTs and BHJ transistors, as well as complementary-like inverters.