Optical and Dynamical Properties of One-Dimensional Excitons in Conjugated Polymers

Abstract

The nature of excitons in conjugated polymers is discussed from a theoretical point of view. An intrachain exciton can be essentially described as a Wannier exciton. However, its one-dimensional character leads to an unusually large binding energy and an unusually small exciton size, for which the electronic correlation length turns out to be a decisive factor. These extraordinary features have important implications on the linear and nonlinear optical properties of conjugated polymers. In addition to these intrachain characteristics of excitons, we discuss the influence of interchain excitation transfer. It is demonstrated that the excitation transfer depends upon the interchain distance and the chain length in a complicated way due to the large molecular size. The limitation of the point dipole approximation as well as that of the extended dipole approximation are elucidated.