High‐Performance Ambipolar Transistors and Inverters from an Ultralow Bandgap Polymer

Ambipolar organic thin-fi lm transistors (OTFTs) with high hole and electron mobilities have attracted considerable attention due to their application in complementary metal-oxide semiconductor (CMOS) digital integrated circuits. [ 1 ] Due to their processing simplicity, solution processable single component ambipolar polymers have great advantage over blend and bilayer systems of unipolar semiconductors in the construction of ambipolar OTFTs. In ambipolar blend systems, the ambipolar charge transport and the associated carrier mobilities in blend system have a complex dependence on the blend composition and the phase-separated morphology, and therefore are highly dependent on processing conditions. [ 1c ] In ambipolar bilayer systems, the bilayer is often fabricated via vacuum deposition of small molecule as solution processed bilayer fi lms are diffi cult to realize since they require the second layer to be processable with solvents orthogonal to that of the initial layer. [ 1e − f ]