Halogenated 6,13-bis(triisopropylsilylethynyl)-5,7,12,14-tetraazapentacene: applications for ambipolar air-stable organic field-effect transistors

Density functional theory calculations were performed to explore the influence of halogenation on the reorganization energies (lambda), adiabatic ionization potentials (IPs), adiabatic electron affinities (EAs), and air stabilities of a series of pentacene (PENT) and tetraceno[2,3-b]thiophene (TbTH) derivatives. According to calculated IP and EA values, all well-known PENT and TbTH derivatives in this paper are air-stable p-channel but not air-stable n-channel organic field-effect transistors (OFETs) due to insufficient EAs, consistent with experimental observations. The calculated results show that attaching two or more halogen atoms onto air-unstable 6,13-bis(triisopropylsilylethynyl)-5,7,12,14-tetraazapentacene (TIPS-N4PENT) is sufficient for promoting ambipolar air-stable properties. The electronic coupling and band structure calculations indicate that halogenated TIPS-N4PENT derivatives have potential applications in high-performance ambipolar air-stable OFETs. They also provide rational guidelines for the design of ambipolar air-stable organic semiconductors (OSCs).