Exciton dynamics in conjugated polymer systems

Exciton dynamics in ? -conjugated polymers systems encompass multiple time and length scales. Ultrafast femtosecond processes are intrachain involve a quantum mechanical correlation of the exciton nuclear degrees freedom. In contrast, post-picosecond incoherent Förster transfer excitons between polymer chains. is also strongly determined by spatial temporal disorder that ubiquitous conjugated polymers. Since delocalized over hundreds atoms, theoretical understanding these only realistically possible employing suitably parametrized coarse-grained exciton-phonon models. Moreover, to correctly account for ultrafast processes, phonon modes must be treated on same basis Ehrenfest approximation abandoned. This further implies sophisticated numerical techniques employed solve review describes our current systems. We begin describing energetic distribution disordered systems, define crucial concept “chromophore” discuss role exciton-nuclear coupling, emphasizing distinction “fast” “slow” freedom determining “self-trapping” “self-localization” exciton-polarons. Next, we decoherence caused entanglement, which leads fluorescence depolarization timescale 10-fs. Interactions with its environment causes stochastic relaxation localization high-energy onto chromophores. The coupling torsional various dynamical processes. On sub-ps timescales it exciton-polaron formation (i.e., local planarization). Conversely, post-ps fluctuations cause diffusion along chain at higher temperatures transient delocalization via extended states. next describe first-principles, Förster-type model interchain condensed phase, whose starting point realistic description donor acceptor Finally, phase highly-ordered nanofibers. survey experimental results explain how they can understood terms coupled information multiscale structures. contains brief critique computational methods simulate dynamics.