Effect of long-range electronic correlation on exciton in the conjugated polymers

With the long-range electronic correlation Hamiltonian model, self-trapped exciton state in conjugated polymer under an electric field is investigated. It is found that the exciton binding energy is reduced by the long-range electronic correlation (LREC) effect compared to that without correlation situation, which means that the LREC effect is advantage for the excitbn to dissociate into two quasi-particles: electron-polaron and hole-polaron. It is found that the LREC energy of the self-trapped exciton state has a bigger change when the applied field is over 4 x 10(5) V/cm at which the self-trapped exciton has been dissociated into two charged-opposite polarons, that is, the LREC energy of the self-trapped exciton state is lower than that of two separated polarons state. It is also found that Hartree-Fock electronelectron (e-e) interaction reduces linear polarizability chi((1)) and third-order nonlinear polarizability chi((3)) of the exciton state, and the long-range electronic correlation effect furthers reducing chi((1)) and chi((3)). (C) 2015 Elsevier B.V. All rights reserved.