Bis(benzoselenadiazol)ethane: A π-Extended Acceptor-Dimeric Unit for Ambipolar Polymer Transistors with Hole and...

The lack of ambipolar polymers with balanced hole (μ_h) and electron mobilities (μ_e) >10 cm² V^-1 s^-1 is the main bottleneck for developing organic integrated circuits. Herein, we show the design and synthesis of a π-extended selenium-containing acceptor-dimeric unit, namely benzo[c][1,2,5]selenadiazol-4-yl)ethane (BBSeE), to address this dilemma. In comparison to its sulfur-counterpart, BBSeE demonstrates enlarged co-planarity, selective noncovalent interactions, polarized Se-N bond, and higher electron affinity. The successful stannylation of BBSeE offers a great opportunity to access acceptor-acceptor copolymer pN-BBSeE, which shows a narrower band gap, lower-lying lowest unoccupied molecular orbital level (-4.05 eV), and a higher degree of backbone planarity. Consequently, the pN-BBSeE-based organic transistors display an ideally balanced ambipolar transporting property with μ_h and μ_e of 10.65 and 10.72 cm² V^-1 s^-1, respectively. To the best of our knowledge, the simultaneous μ_h/μ_e values >10.0 cm² V^-1 s^-1 are the best performances ever reported for ambipolar polymers. In addition, pN-BBSeE shows an excellent shelf-storage stability, retaining over 85 % of the initial mobility values after two months storage. Our study demonstrates the π-extended acceptor-dimeric BBSeE is a promising acceptor building block for constructing high-performance ambipolar polymers applied in next-generation organic integrated circuit.