A THEORETICAL INVESTIGATION ON THE PROPERTIES OF CHARGE TRANSPORT OF HEXAAZATRINAPHTHYLENE DERIVATIVES

Abstract

A hexaazatrinaphthylene [HAT] is a well-known halogenated perylene diimide compound recognized for photochemical stability, high electron affinity, easy functionalization, and high conductivity. Based on density functional theory, optoelectronic and charge transport properties of HAT derivatives with electron-donating, electron-withdrawing, and push-pull substituents, were investigated. The impact of substituting electron-withdrawing groups (EWG), electron-donating groups (EDG), and push-pull substituents on various aspects, including molecular structure, frontier molecular orbitals, ionization energy, electron affinity, reorganization energy, crystal packing, and charge carrier mobility, is investigated. A crystal structure simulation method is employed to optimize potential arrangements of crystal packing for the molecules under examination. The presence of EWG, EDG, and push-pull substitutions significantly affects the energy and distribution of electron density in the frontier molecular orbitals, leading to alterations in the absorption spectrum and charge transport properties. When adding various substituents to the core system, the different crystal packing motifs and varied intermolecular interactions of the examined molecules result in noticeably different transfer integrals. Due to higher hole reorganization energy and weak HOMO orbital overlapping, HAT derivative molecules exhibit better electron mobility. Among the studied molecules, HAT-F and HAT-F-OCH3 molecules demonstrate better electron mobility with values of 0.49 and 2.36 cm2 V−1 s−1, respectively, and established the n-channel characteristics.