Density matrix renormalization group study of conjugated polymers with transverse pi-conjugation

TL;DR

This study uses density matrix renormalization group methods to analyze excited state orderings in hypothetical conjugated polymers with transverse pi-conjugation, revealing conditions favorable for photoluminescence.

Contribution

It presents the first detailed numerical analysis of excited states in modified Hubbard models for polymers with transverse conjugation, highlighting potential for optoelectronic applications.

Findings

Excited state ordering can be tuned by Coulomb repulsion.

Substituted polymers show photoluminescence potential.

Opposite excited state ordering compared to unsubstituted polyenes.

Abstract

We report accurate numerical studies of excited state orderings in long hypothetical pi-conjugated oligomers in which the hydrogen atoms of trans-polyacetylene are replaced with conjugated sidegroups, within modified Hubbard models. There exists a range of the bare Coulomb repulsion for which the excited state ordering is conducive to photoluminescence in the substituted systems, even as this ordering is opposite in the unsubstituted polyenes of the same lengths. Our work provides motivation to study real pi-conjugated polymers with transverse conjugation and small optical gaps.