Air-Stable, Solution-Processable n-Channel and Ambipolar Semiconductors for Thin-Film Transistors Based on the Indenofluorenebis(dicyanovinylene) Core

摘要

The development of solution-processable small-molecule and polymeric semiconductors for field-effect transistors (FETs) exhibiting high carrier mobility and good ambient stability is crucial to realizing low-cost and mechanically flexible printed electronics. During the past decade, intense research efforts have yielded a number of air-stable p-channel (hole-transporting) and n-channel (electron-transporting) semiconductors. Nevertheless, very few solution-processable, air-stable n-channel materials are known. Furthermore, known examples generally exhibit modest FET performance (μ_e≈0.01-10~(-5)cm~2 V~(-1)s~(-1))~4 versus the corresponding vacuum-deposited films (μ_e≈0.64-0.01 cm~2 V~(-1)s~(-1)), likely reflecting microstructural irregularities in the solution-processed films. Realization of air-stable, solution-processable, n-channel molecules and polymers is important for p-n junctions, bipolar transistors, organic complementary circuitry (CMOS), and for stimulating fundamental research on OFET charge transport. Recently, a solution-processable dicyanomethylene-substituted ter-thienoquinoid derivative was reported to exhibit μ_e≈0.16 cm~2 V~(-1) s~(-1) in air, however it suffers from a low I_onII_off ratio (ca. 10~3-10~4) and μ_e drops to ca. 0.01 cm~2 V~(-1) s~(-1) over time in ambient conditions. Importantly, the paucity of air-stable n-channel polymers has significantly hindered utilizing the superior rheological properties of polymers in printing processes.