Polarized superradiance from delocalized exciton transitions in tetracene single crystals

Polarized superradiant emission and exciton delocalization in tetracene single crystals are reported. Polarization-, time-, and temperature-resolved spectroscopies evidence the complete polarization of the zerophonon 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 in the radiative lifetime with temperature, being 15 times shorter at 30 K compared to the isolated molecule, with an exciton delocalization of about 40 molecules.