Reorganization energy is one of the important factors to decide the rate of
electron transfer according to the Marcus theory. Small reorganization
energy is highly desirable in design of optoelectronic and electronic
devices like as organic light emitting diode. For this reason,
reorganization energy of aromatic diamine derivatives,
N,N′-diphenyl-N,N′-bis(3-methylphenyl)-
(1,1′-biphenyl)-4,4′-diamine (TPD) and
4,4′-diphenyl-N,N,N′,N′-tetraphenylbenzidine (DTPB) have
been studied theoretically by self-exchange electron transfer theory. By
executing the Gaussian 03 calculation we can easily figure out the
optimization point which needed for calculation of the inner reorganization
energy (λ) of self-exchange electron transfer reaction. Also ionization
potential and electron affinities of these molecules can be calculated at
the density functional theory level with basis set 6-31G** and
6-31G* using Gaussian 03 software on the basis of
ab initio method. It gives possibility to develop a
semi-empirical model for the observed absorption and photoluminescence
spectrum.