Azaborine Compounds for Organic Field‐Effect Transistors: Efficient Synthesis, Remarkable Stability, and BN Dipole Interactions

Abstract

Organic semiconductors have attracted great attention during the past few decades for the development of next-generation electronics. The incorporation of a B N unit, which is isoelectronic to the C=C moiety, into p systems provides a novel approach in the molecular engineering of organic semiconductors. BN substitution can change the electronic properties of p systems, and afford additional intermolecular dipole–dipole interactions. Therefore, BN-incorporated semiconductors provide new opportunities for organic electronics. Although significant progress has been made in azaborine chemistry, the construction of azaborine rings in large p scaffolds remains challenging. Moreover, azaborine compounds are usually susceptible to moisture and oxygen, and their thermal decomposition temperatures are around 200 8C, thus limiting their promising applications as organic materials. As a result, the charge-transport properties of azaborine compounds have rarely been investigated up to now. Only recently, Nakamura and co-workers reported a BN-fused polycyclic aromatic compound which exhibited higher intrinsic hole mobility than its carbon analog by timeresolved microwave conductivity measurements, implying that BN-substituted aromatics might outperform their carbon analogs in organic electronics. Nonetheless, electronic devices based on azaborine compounds have not yet been demonstrated. Herein, we synthesize two novel BN-substituted tetrathienonaphthalene derivatives BN-TTN-C3 and BN-TTN-C6 through an efficient one-pot electrophilic borylation method (Scheme 1). Four thiophene rings are fused onto a BNsubstituted naphthalene core to extend the p conjugated plane for intermolecular p–p stacking and charge-carrier