Mean distance that an exciton travels from the site of its creation to the site where it radiatively or non-radiatively decays or dissociates into
charge carriers.
Source:
PAC, 2022, 94, 15. 'Glossary of terms relating to electronic, photonic and magnetic properties of polymers (IUPAC Recommendations 2021)' on page 31 (https://doi.org/10.1515/pac-2020-0501)