Low energy exciton pocket at finite momentum in tetracene molecular solids

TL;DR

This study reveals an anisotropic exciton bandstructure in tetracene with a finite momentum energy minimum, which could influence photophysical processes and device applications in organic semiconductors.

Contribution

It demonstrates the existence of a low energy exciton pocket at finite momentum in tetracene, highlighting the importance of momentum-dependent effects in organic semiconductors.

Findings

Anisotropic exciton bandstructure in tetracene

Existence of a low energy exciton pocket at finite momentum

Implications for photophysical behavior and organic solar cells

Abstract

The excited state dynamics in organic semiconductors plays an important role for many processes associated with light absorption and emission. We have studied the momentum dependence of the lowest singlet excitons in tetracene molecular solids, an archetype system for other organic semiconductors. Our results reveal an anisotropic bandstructure of these excitons with an energy minimum at finite momentum, i. e., a low energy exciton pocket. The existence of such low energy states might have important consequences for the photophysical behavior, also in view of applications in, e. g., organic solar cells. Our studies stress the importance of momentum dependent considerations in organic systems.