We study the charge transport by polarons in conjugated polymers in the presence of impurities. The effects on the polaron motion due to the symmetry of the chain is considered. The polaron dynamics in doped conjugated polymers is numerically studied using the Su-Schrieffer-Heeger (SSH) model combined with the Pariser-ParrPople (PPP) model modified to include an external electric field and the ...

Scattering process between a negative polaron and an exciton in a polymer chain is investigated by using the Su-Schrieffer-Heeger model modified to include electron-electron interactions, the Brazovskii-Kirova symmetry breaking term, and an external electric field. It is found that the scattering process is spin dependent. If the polaron and the exciton have parallel spins, the polaron can easi...

The main objective of this thesis is to provide a deeper understanding of the charge transport phenomena occuring in molecular crystals. The focus is on the stability and the dynamics of the polaron as the charge carrier. To achieve this goal, a series of numerical calculations are performed using the semi-emprical "Holstien-Peierls" model. The model considers both intra(Holstein) and inter(Pei...

A system of a single relativistic electron interacting with the quantized electromagnetic field is considered. We mainly study this system with a fixed total momentum p — This system is called the Dirac polaron. We analyze the lowest energyE(p) of the Dirac polaron, and derive some properties: concavity, symmetricity, and the inverse energy inequality E(p) ≤ E(0), p ∈ R. Furthermore, we conside...

The photophysics of MEH-PPV incorporated into the pores of periodic silica hosts has been investigated in an effort to understand the role played by interchain aggregation and chain morphology in polaron production. In this work, guest/host interactions were used to incorporate MEH-PPV into the straight, homogeneous pores of hexagonal surfactant- or polymer-templated mesoporous silicas of varyi...

Moving electrons accompanied by Jahn-Teller phonon and spin-wave clouds may form composite polarons in ferromagnetic narrow-band manganites. The ground-state and the finite-temperature properties of such composite polarons are studied in the present paper. By using the variational method, it is shown that the energy of the system at zero temperature decreases with the formation of the composite...

I give a brief overview of a polaron formation in three distinct transition metal oxides: (i) spin polaron when a hole is added to the antiferromagnetic (AF) ordered plane in La2CuO4, (ii) orbital polaron when a hole is added to the alternating orbital (AO) ordered plane in LaMnO3, and (iii) spin-orbital polaron when a hole is added to the AF and AO ordered plane in LaVO3. Comparison of the dis...

Method of intermediate problems in the theory of linear semi-bounded self-adjoint operators on rigged Hilbert space was applied to the investigation of the ground state energy of the Fröhlich polaron model. It was shown that various infinite sequences of non-decreasing improvable lower bound estimates for the polaron ground state energy can be derived for arbitrary values of the electron-phonon...

Exciton dissociation in a donor-accepter polymer heterojunction has been simulated using a nonadiabatic molecular dynamics approach, which allows for the coupled evolution of the nuclear degrees of freedom and the electronic degrees of freedom described by multiconfigurational electronic wavefunctions. The simulations reveal important details of the charge separation process: the exciton in the...

Dynamical simulations of polaron transport in conjugated polymers in the presence of an external time-dependent electric field have been performed within a combined extended Hubbard model (EHM) and Su-Schrieffer-Heeger (SSH) model. Nearly all relevant electron-phonon and electron-electron interactions are fully taken into account by solving the time-dependent Schrödinger equation for the pi ele...