First-principles Band Structures Calculation of Tin-phthalocyanine

We adopt the density function theory with generalized approximation by the Beeke exchange plus Lee-Yang-Parr correlation functional to calculate the electronic first-principles band structure of tin-phthalocyanine (SnPc).The intermolecular interaction related to transport behavior was analyzed from the ?-point wave function as well as from the bandwidths and band gaps.From the calculated bandwidths of the frontier bands as well as the effective masses of the electron and hole, it can be concluded that the mobility of the electron is about two times larger than that of the hole.Furthermore, when several bands near the Fermi surface are taken into account, we find that the interband gaps within the unoccupied bands are generally smaller than those of the occupied bands, indicating that the electron can hop from one band to another which is much easier than the hole. This may happen through electron-phonon coupling for instance, thus effectively yielding an even larger mobility for the electron than for the hole. These facts indicate that in SnPc the electrons are the dominant carriers in transport, in contrast to most organic materials.