Physical and chemical properties of conjugated organic polymers with π-electrons have
been interpreted in terms of self-localized excitations, which are quasi-particles
with structural changes over several repeating units. These excitations can be classified
into
solitons,
polarons,
bipolarons and
excitons according to their charge and spin.
Source:
PAC, 2007, 79, 293
(Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006))
on page 419