A single polymer chain as an organic quantum wire: optical evidence of a purely 1D density of states

TL;DR

This study provides optical evidence that isolated polydiacetylene polymer chains act as perfect one-dimensional semiconducting wires with a characteristic density of states, temperature-dependent broadening, and specific phonon coherence times.

Contribution

It demonstrates that a single polymer chain exhibits purely 1D density of states and characterizes its optical phonon coherence times.

Findings

Chains behave as perfect 1D semiconducting wires

Density of states follows 1/√E between 5 and 50 K

Optical phonons have coherence times of 300-600 fs

Abstract

The excitonic luminescence of an isolated polydiacetylene polymer chain in its monomer matrix is studied by micro-photoluminescence. These chains behave as perfect 1D semiconducting wires with the expected 1/$\sqrt{E}$ density of states between 5 and 50 K. The temperature dependence of the homogeneous width is explained by interaction with longitudinal acoustic phonons of the crystal in the range of temperature explored. The optical phonons of the chain which are involved in the vibronic transitions are found to have coherence times ranging from 300 to 600 fs.