Using a temperature (T)-dependent tight-binding (TB) model for an electron-hole pair at the donor-acceptor (DA) interface, we investigate the dissociation of charge transfer exciton (CTE) into free carriers, that is, an electron and a hole. We observe the existence of the localization-delocalization transition at a critical T, below which the charges are localized to the DA interface, and above which the charges are delocalized over the system. This explains the CTE dissociation observed in organic solar cells. The present study highlights the combined effect of finite T and carrier delocalization in the CTE dissociation.
Part of the book: Excitons