Photoinduced Ultrafast Process of Relaxation in Polymer

On the basis of multi-phonon transition theory. the origin of the fast component (100 fs) and the slow component(ns) in photoexcitation dynamics is explained and their evolution time is calculated. From these results, it is seen that the fast component is duo to the formation from free electron-hole pair to neutral bipolaron, and the slow one is due to the non-radiative decay of bipolaron.