<i>Ab initio</i> study of electron and hole transport in a naphthalene crystal including polaron effects

Organic semiconductors have broad applications in electronics, but their transport properties are notoriously difficult to predict due to their complex structure, strong electron-phonon (e-ph) interactions and localized charge carriers (polarons). We recently showed [1] calculations of the hole mobility in naphthalene, assuming band-like transport and using lowest-order ab initio e-ph interactions within the Boltzmann equation approach. Although our calculations provided hole mobilities in agreement with experiment, several open questions remain, such as improving the accuracy of the method and extending it to charge transport in the polaron regime. In this work, we employ our recently developed finite-temperature cumulant-expansion method [2] to compute the electron spectral functions, and from them the mobility, in a naphthalene crystal. Our method can correctly include strong e-ph interactions and polaron effects. We will discuss the carrier spectral functions and mobilities as a function of temperature in naphthalene, comparing the results with experiments and lowest-order theory. The applicability of our method to a range of organic crystals will be discussed.

1. N.-E. Lee et al., Phys. Rev. B 97, 115203 (2018)
2. J.-J. Zhou et al., arXiv:1905.03414v2 (2019)