ИСТИНА

Being typically excited at room temperature, low-frequency (LF) intermolecular vibrational modes in crystalline organic semiconductors are known to have a considerable impact on the charge carrier mobility in such materials, representing a kind of dynamic disorder. Although the issue has been addressed within a number of frameworks, LF intermolecular vibrations are typically considered classically within them. To shed light onto the effect of phonon correlations in the LF regime, we make an LF expansion in a Holstein–Peierls model for a two-site cluster and a 1D chain of molecular sites in a fully quantum way. It turns out that such an expansion leads to intermediate-time plateaus signaling the phenomenon of transient localization, which gives way to further delocalization due to higher-order terms. We analyze the agreement of this behavior with the predictions of the semiclassical framework, and discuss the drivers of charge-carrier mobility in light of LF phonon modes.