[en] We numerically investigate the injection process of electrons from metal electrodes to one-dimensional organic molecules by combining the extended Su—Schrieffer—Heeger (SSH) model with a nonadiabatic dynamics method. It is found that a match between the Fermi level of electrodes and the highest occupied molecular orbital (HOMO) or the lowest unoccupied molecular orbital (LUMO) of organic molecules can be greatly affected by the length of the organic chains, which has a great impact on electron injection. The correlation between oligomers and electrodes is found to open more efficient channels for electron injection as compared with that in polymer/electrode structures. For oligomer/electrode structures, we show that the Schottky barrier essentially does not affect the electron injection as the electrode work function is smaller than a critical value. This means that the Schottky barrier is pinned for a small work-function electrode. For polymer/electrode structures, we find that it is possible for the Fermi level of electrodes to be pinned to the polaronic level. The condition under which the Fermi level of electrodes exceeds the polaronic level of polymers is shown to not always lead to spontaneous electron transfer from electrodes to polymers. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

[en] The control of exciton transport in conjugated polymers is of fundamental importance for luminescence and photovoltaic properties of polymeric optoelectronic devices. We have investigated the elastic scattering processes of a negative polaron and a neutral exciton in a conjugated polymer chain in the presence of an external electric field. We demonstrate that the exciton can be pushed or pulled to transport in a given direction by the polaron, or migrate by exchanging positions with the polaron in particular range of electric field strength. The exciton can preserve quantum coherence in these field induced transfer processes. The manner of exciton motion depends on the spin configuration of the exciton and the polaron as well as the electric field strength. This knowledge will serve to understand the dynamics of intrachain energy transport in conjugated polymers. -- Highlights: ► Neutral exciton can be controlled to move by electric fields by interacting with a polaron. ► Triplet excitons can be pushed or pulled by moving polarons. ► Singlet excitons can only be pulled by moving polarons. ► Both triplet and singlet excitons can perform a hopping like migration by exchanging positions with a moving polaron.