Ab initio computational studies on the structures and energetics of hole transport molecules: Triphenylamine

Triphenylamine neutral and hole (radical cation) molecules are optimized by ab initio Hartree-Fock calculations at the 3-21G basis set. Modest changes in geometry are computed upon oxidation. The unpaired electron is 59% localized on the amine nitrogen atom. The energy barrier for the hopping process involving the electron transfer between a neutral and ionized (hole) triphenylamine is 0.15 eV. The vibrational mode that is primarily associated with the change in geometry upon hole formation is the C-N stretching mode.