We proposed a multi-scale computational framework based on a wave-packet propagation with a nonlinear tight-binding Huckel model and molecular dynamics with a density functional method, and adopted the multi-scale approach to carrier transport of organic polymers showing dynamic structural fluctuations. In the tight-binding Huckel Hamiltonian, we introduced an electron-hole binding energy, the non-linear term in the present method, and investigated the influence of the electron-hole binding on the carrier mobility. We conducted wave-packet propagation for 5 ps dynamics on two kinds of polymers with 1 mm length. We found that when the electron-hole binding energy is changed from 0 to 500 meV, the carrier mobility can be changed by two orders of magnitude. We also analyzed the localization property of the wave-packet on the polymers, and found that (1) in both small and large electron-hole binding regimes, the orbital localization simply causes the decrease in carrier mobility, and (2) in an intermediate electron-hole binding regime, the orbital localization rather enhances the carrier mobility.
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