Deciphering the Multifarious Charge‐Transport Behaviour of Crystalline Propeller‐Shaped Triphenylamine Analogues

Abstract

A collection of para‐substituted propeller-shaped triphenylamine (TPA) derivatives have been computationally investigated for the charge transport characteristics exhibited by the derivatives using the Marcus‐Hush formalism. The various substituents chosen in the current work, having features that range from electron withdrawing to electron donating nature, play a key role in defining the reorganization energy and electronic coupling properties of the TPA derivatives. TPA moiety is expected to possess weak electronic coupling on the basis of poor orbital overlap upon aggregation owing to the restriction imposed by the propeller shape of the triphenylamine core. However, the substituent groups attached to the TPA core can significantly dictate the crystal packing motif of the TPA derivatives, wherein the variety of noncovalent intermolecular interactions subsequently generated drive the packing arrangement and influence the electronic coupling between the neighbouring orbitals. The intermolecular interactions in the crystalline architecture of TPA derivatives were probed using Hirshfeld and QTAIM techniques. Furthermore, SAPT analysis of the TPA analogues has revealed that a periodic arrangement of energetically stable dimers having significant electronic coupling is essential in order to contribute a high charge carrier mobility to the overall crystal.