First-principles electronic structure of copper phthalocyanine (CuPc)

Copper phthalocyanine (CuPc), was reported to have high electron mobility. In order to gain a deeper understanding for its carrier transport properties, we adopt the density functional theory (DFT) with generalized gradient approximation (GGA) to calculate the electronic band structure by the Becke exchange plus Lee–Yang–Parr correlation (BLYP) functional. The intermolecular interaction related to transport behavior has been analyzed from the bandwidths and band gaps. Within the effective mass approximation, we conclude that the interband gaps within the unoccupied bands are generally smaller than those for the occupied bands, which indicate that the electron can hop through scattering from one band to another, much easier than the hole. These facts indicate that, in CuPc the electron are the dominant carriers in transport, in contrast to most organic materials.