Revealing the Electron-Phonon Coupling in a Conjugated Polymer by Single-Molecule Spectroscopy

Electron–phonon coupling in a π‐conjugated polymer is revealed by single‐molecule spectroscopy in combination with statistical pattern recognition techniques. The technique allows to reveal the phonon‐side band in the spectra of methyl‐substituted ladder‐type poly(para‐phenylene) (see figure). For this polymer a weak electron–phonon coupling strength is found at low temperatures. The distribution of the phonon frequencies provides strong evidence that the low‐energy vibrational modes, which couple to the electronic transitions, stem from vibrations of the host matrix.