Phonon-limited Hole Mobility in Naphthalene Crystal from ab initio Band Theory

We compute from first principles the electron-phonon scattering and the phonon-limited hole mobility of naphthalene crystal in the framework of ab initio band theory. Our calculations combine GW electronic bandstructures, ab initio electron-phonon scattering, and the Boltzmann transport equation. The calculated hole mobility is in very good agreement with experiment between 100−300 K, and we can predict its temperature dependence with high accuracy. We show that inter-molecular phonons control the mobility due to their large scattering phase space near the band edge, but contrary to common notions, intra-molecular phonons possess the strongest coupling to holes. Our work provides a quantitative framework for computing charge transport in organic crystals, and is a first step toward reconciling band-like transport with carrier hopping in organic semiconductors.