Effects of thermal expansion and degeneracy on ambipolar carrier mobility of non-peripherally hexyl-substituted phthalocyanine

Abstract

Abstract The origin of the negative temperature dependence of carrier mobility in a crystal phase of 1,4,8,11,15,18,22,25-octahexylphthalocyanine was studied by utilizing a charge transport simulation based on Marcus theory and density functional theory. In order to understand the unique negative temperature dependence of carrier mobility, the theoretical calculation was carried out by taking the thermal expansion of the lattice parameters into consideration. The calculated hole mobility exhibited the similar temperature dependence as the experimental results. In the electron mobility calculation, the negative temperature dependence could be simulated by considering the degeneracy of lowest unoccupied molecular orbitals as well as the thermal expansion.