Charge-transfer in soliton and polaron states of phenyl-substituted polyacetylenes

Within a tight-binding Su-Schrieffer-Heeger model, we have investigated soliton and polaron excitations in phenyl-substituted polyacetylenes (PDPA and PPA). PDPA (PPA) is a light (non-)emitting polymer with two degenerate ground states. Charge transfer between phenyls and polyacetylene chain, resulting from their π-electron coupling, has been found in these excited states. The amount of transferred charge depends on the position of phenyls in the main chain for PPA and is smaller than that for PDPA, which is in agreement with the previous result that the electron correlation is reduced in PDPA.