Polarized superradiant emission and exciton delocalization in tetracene single crystals are reported. Polarization-, time-, and temperature-resolved spectroscopy evidence the complete polarization of the zero-phonon line of the intrinsic tetracene emission from both the lower (F state) and the upper (thermally activated) Davydov excitons. The superradiance of the F emission is substantiated by a nearly linear decrease of the radiative lifetime with temperature, being fifteen times shorter at 30 K compared to the isolated molecule, with an exciton delocalization of about 40 molecules.
@article{arxiv.1304.7958,
title = {Polarized superradiance from delocalized exciton transitions in tetracene single crystals},
author = {Andrea Camposeo and Marco Polo and Silvia Tavazzi and Leonardo Silvestri and Peter Spearman and Roberto Cingolani and Dario Pisignano},
journal= {arXiv preprint arXiv:1304.7958},
year = {2013}
}