Low-temperature electronic structures and intramolecular interaction of oligofluorenes studied by synchrotron photoemission spectroscopy

Influences of temperature and intramolecular interaction on the electronic structures of oligofluorenes were systematically studied via synchrotron radiation photoemission spectroscopy and quantum chemical calculations. Our results show that the oligofluorene thin films deposited at substrates of different temperatures will alter the electronic structures, which results from the change of interunit angles in 2,7-bis[9,9-di(4-methylphenyl)-fluoren-2-yl]- 9,9-di(4-methylphenyl)fluorine molecules. The fluorene-units at low temperature are almost perpendicular to each other and the interunit angle of stable state is 41° at room temperature. © 2009 American Institute of Physics.