Emission of a Single Conjugated Polymer Chain Isolated in Its Single Crystal Monomer Matrix

Abstract

The excitonic luminescence of a highly ordered single conjugated polymer chain is studied by microphotoluminescence. At $T\ensuremath{\le}10\mathrm{K}$ it consists of a single Lorentzian line. The linewidth increases linearly with $T$ between 6 and 60 K, from $350\ensuremath{\mu}\mathrm{eV}$ at 6 K, indicating a pure dephasing time of $\ensuremath{\sim}2\mathrm{ps}$. Above 10 K, other neighboring regions along the chain direction start to emit at a slightly higher (by $\ensuremath{\sim}1\mathrm{meV}$) energy. This indicates very small inhomogeneous broadening, very long chains ( $\ensuremath{\ge}10\ensuremath{\mu}\mathrm{m}$), and a long range and very rapid exciton energy transfer ( $>10\ensuremath{\mu}\mathrm{m}$ in $<100\mathrm{ps}$).