Designing pi-conjugated polymers with light emission in the infrared

TL;DR

This paper explores the theoretical design of pi-conjugated polymers capable of infrared light emission, highlighting structural features that reduce Coulomb correlation to enable IR emission.

Contribution

It demonstrates that specific structural arrangements in polymers can achieve IR emission by reducing effective Coulomb correlations, a novel design principle.

Findings

Infrared emission can be achieved in designer polymers with reduced Coulomb correlation.

Transverse pi-conjugation over a few bonds is essential for small Coulomb correlations.

Structural design influences the electronic properties necessary for IR emission.

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 emission in the IR can be achieved in designer polymers in which the effective Coulomb correlation is smaller than that in existing systems. We also show that the structural requirement for having small effective Coulomb correlations is that there exist transverse $\pi$--conjugation over a few bonds in addition to longitudinal conjugation with large conjugation lengths.