Comment on "Triplet-to-Singlet Exciton Formation in poly(p-phenylene-vinylene) Light-Emitting Diodes"

TL;DR

This paper critically evaluates a proposed mechanism for exciton formation in conjugated polymers, demonstrating that the phonon bottleneck concept for triplets in polyenes is incorrect based on theoretical spectra.

Contribution

It provides a theoretical critique of Lin et al.'s mechanism, showing that their phonon bottleneck hypothesis for triplet formation in polyenes is invalid.

Findings

The proposed phonon bottleneck for triplets does not exist in theoretical spectra.

The mechanism explaining singlet-triplet yield ratios in conjugated polymers is incorrect.

Theoretical spectra challenge previous explanations of exciton formation dynamics.

Abstract

The low-lying singlet and triplet spectrum in conjugated polymers clearly show that the mechanism proposed by Lin et al. to explain their electric field dependence of singlet to triplet yield ratios is wrong. This comment, from theoretical spectrum obtained for long polyenes, shows that the phonon bottleneck proposed by Lin et al. for triplets in polyenes cannot exist.