[20p-231C-1~9] Frontier of organic semiconductor crystals: Toward the Molecular Science of Quantum Liberated Electrons

[20p-231C-3] First-Principles Investigation of Excited States of High-Mobility Organic Semiconductors

〇Takatoshi Fujita¹ (1.IMS)

Keywords:Organic semiconductor, Exciton, First-principles calculations

Electronically excited states of organic molecular aggregates have been understood in terms of Frenkel exciton model which is based on tightly-bound electrons. However, recent discovery of high-mobility organic semiconductors imply that electrons in molecular crystals can be highly delocalized over many molecules. Therefore, a more general exciton model, which includes both Frenkel and Wannier exciton model, should be established to understand the excited states in high-mobility organic semiconductors. We have studies optical properties and exciton dynamics in organic semiconductors by combining large-scale electronic structure calculations by fragment molecular orbital method and quantum dynamics theory. In the talk, I will present recent researches on exciton dynamics in an organic semiconductor thin film and interfacial charge transfer states in an organic/organic interface. In particular, I will highlight the mixing between intramolecular excited states (or Frenkel exciton states) and charge-transfer states and the localization and delocalization of electron and hole wave functions.