Electron-hole versus exciton delocalization in conjugated polymers: the role of topology

TL;DR

This paper develops a theoretical framework to predict exciton delocalization in conjugated polymers based on their topology, aiming to identify structures suitable for infrared light emission in solid-state lasers.

Contribution

It introduces a novel theory linking polymer topology to exciton delocalization, guiding the design of IR-emitting conjugated polymers.

Findings

Exciton delocalization extent can be predicted from polymer topology.

Structural characteristics for IR emission are identified.

A theoretical basis for designing IR-emitting polymers is established.

Abstract

There is currently a great need for solid state lasers that emit in the infrared. Whether or not conjugated polymers that emit in the IR can be synthesized is an interesting theoretical challenge. We show that the requirement for such a material is that the exciton delocalization in the system be large, such that the optical gap is small. We develop a theory of exciton delocalization in conjugated polymers, and show that the extent of this can be predicted from the topology of the conjugated polymer in question. We determine the precise structural characteristics that would be necessary for light emission in the IR.