Weak intermolecular charge transfer in the ground state of a $\pi$-conjugated polymer chain

We show that a $\pi$-conjugated polymer chain can demonstrate weak intermolecular charge transfer in the electronic ground state. Poly[2-methoxy-5-(2`-ethyl-hexyloxy)-1,4-phenylene vinylene]/2,4,7-trinitrofluorenone (MEH-PPV/TNF) donor-acceptor films have been studied by optical absorption, Raman, infrared spectroscopy, and differential scanning calorimetry. The factors influencing weak intermolecular charge transfer in $\pi $-conjugated chains are discussed.