title: Emission Behavior of Crystalline 1,4-Bis(4-phenylthiophene-2-yl)benzene Film Under Optical Excitation with Ultra Short Pulses.
abstract: We evaluated emission behaviors of crystallized films of 1,4-bis(5-phenylthiophene-2-yl)benzene (AC5) in detail which was a representative thiophene/phenylene co-oligomer. The crystallized AC5 films were prepared by vapor deposition onto a substrate and thermal treatment. The AC5 films consisted of a crystalline domain with the size of several tens of micrometers. We used femtosecond laser pulses for the excitation of the AC5 films. As a result, the femtosecond laser pulses did not induce re-absorption above excitation energy densities of their laser threshold. The obtained gain value for AC5 crystallized film was large, over 150 cm-1. Furthermore, the emission cross section of the crystallized AC5 film was nearly 10(-16) cm2.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Mochizuki
authors.forename: Yoshizo
authors.initials: Y
authors.lastname: Kawaguchi
authors.forename: Fumio
authors.initials: F
authors.lastname: Sasaki
authors.forename: Shu
authors.initials: S
authors.lastname: Hotta