ИСТИНА

Adequate description and efficient computation of charge-transfer properties of realistic organic materials constitute one of the major challenges of ongoing materials research for organic electronics. A powerful strategy for this challenge is presented by multiscale modeling , which combines a series of models and computational methods working on different spatial scales, from the atomic to the mesoscale and the scale of an actual device. Within the multiscale modeling methodology, we calculate charge-carrier mobilities of small-molecule organic crystals, accounting for polaronic effects. Starting from transfer integrals and electron-vibron couplings extracted from DFT simulations of single molecules and small crystalline samples, we then study the Holstein–Peierls model of a crystal thus parametrized. Following a recently developed approach within the latter model, we extend the mean-field polaron theory to beyond the small-polaron approximation, so that polarons form bands (see Fig. 1(a)). This lets us probe the parameter region between the hopping and band-transport regimes, where the mobility may drastically increase, due to a non-trivial interplay between the so-called polaron and phonon correlators1, 2 (see Fig. 1(b, c, d)). The method and its implementation we have developed are to be further applied to materials used in organic field-effect transistors and solar cells, as well as biocompatible materials.