東京大学岡本先生との共同研究によるルブレン単結晶のポンプ・プローブ分光の論文が Physical Review Letters オンライン版に掲載されました。
- Relaxation Dynamics of Photoexcited Excitons in Rubrene Single Crystals Using Femtosecond Absorption Spectroscopy
S. Tao, N. Ohtani, R. Uchida, T. Miyamoto, Y. Matsui, H. Yada, H. Uemura, H. Matsuzaki, T. Uemura, J. Takeya, and H. Okamoto
Phys. Rev. Lett. 109, 097403 (2012).
The relaxation dynamics of an exciton in rubrene was investigated by femtosecond absorption spectroscopy. Exciton relaxation to a self-trapped state occurs via the coherent oscillation with 78 cm-1 due to a coupled mode of molecular deformations with phenyl-side-group motions and molecular displacements. From the temperature dependence of the decay time of excitons, the energy necessary for an exciton to escape from a self-trapped state is evaluated to be ∼35 meV (∼400 K). As a result, a self-trapped exciton is stable at low temperatures. At room temperature, excitons can escape from a self-trapped state and, subsequently, they are dissociated to charged species. The exciton dissociation mechanism is discussed on the basis of the results.