Long-range excitons in conjugated polymers with ring torsions

TL;DR

This paper investigates how ring torsions influence long-range excitons in conjugated polymers, revealing that torsions significantly affect excitonic properties, especially in polyaniline due to its larger torsion angles and bond modulation.

Contribution

The study introduces an intermediate exciton formalism to analyze the impact of ring torsions on optical excitations in PPP and PAN, highlighting differences between the two polymers.

Findings

Ring torsions significantly affect long-range excitons in PAN.

Torsion effects are more pronounced in PAN due to larger torsion angles.

Long-range oscillator strengths are modulated by ring torsions.

Abstract

Ring torsion effects on optical excitation properties in poly(para-phenylene) (PPP) and polyaniline (PAN) are investigated by the intermediate exciton formalism. Long-range excitons are characterized, and the long-range component of the oscillator strengths is calculated. We find that ring torsions affect the long-range excitons in PAN more easily than in PPP, due to the larger torsion angle of PAN and the large number of bonds whose hopping integrals are modulated by torsions.