2006/07/24 by William Barford, Barford, William, Christopher D. P. Duffy +2
Biochemistry, Genetics and Molecular Biology · Engineering · Materials Science · Physics and Astronomy · #Chemical Physics (physics.chem-ph) #Conducting polymers and applications #Electron Spin Resonance Studies #FOS: Physical sciences #Organic Electronics and Photovoltaics #physics.chem-ph
paper · pdf · doi:10.48550/arxiv.physics/0607211
Accepted for publication in Phys. Rev. B. (July 2006). 19 pages and 8 figures
arxiv created 2006/07/24 · openalex publication_date 2006/07/24 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The cross-over from coherent to incoherent exciton transport in disordered polymer films is studied by computationally solving a modified form of the Redfield equation for the exciton density matrix. This theory models quantum mechanical (ballistic) and incoherent (diffusive) transport as limiting cases. It also reproduces Forster transport for certain parameter regimes. Using model parameters appropriate to polymer thin films it is shown that short-time quantum mechanical coherence increases the exciton diffusion length. It also causes rapid initial energy relaxation and larger line widths. The route to equilibrium is, however, more questionable, as the equilibrium populations of the model do not satisfy the Boltzmann distributions over the site energies. The Redfield equation for the dimer is solved exactly to provide insight into the numerical results.