Excitation Dynamics in Disubstituted Polyacetylene

Abstract

We studied the excitation dynamics in films of disubstituted polyacetylene, a degenerate ground-state conjugated polymer, using psec transient and steady-state spectroscopies. The polymer is found to support charged and neutral topological soliton excitations concurrent with a strong intrinsic photoluminescence band with quantum efficiency, $\ensuremath{\eta}\ensuremath{\simeq}50%$. This leads to stimulated emission in thin films and lasing in cylindrical $\ensuremath{\mu}$ cavities. The seeming contradiction of a degenerate ground-state polymer with high $\ensuremath{\eta}$ is explained by the lowest excited-state ordering.