title: Blue emitting 3π-2spiro terfluorene-indenofluorene isomers: a structure-properties relationship study.
abstract: Two novel terfluorenyl derivatives, 2,2'',7,7''-tetrakis(9,9-dioctyl-9H-fluoren-2-yl)dispiro[fluorene-9,11'-indeno-(2,1-a)-fluorene-12',9''-fluorene] ((2,1-a)-DST-IF) and 2,2'',7,7''-tetrakis(9,9-dioctyl-9H-fluoren-2-yl)dispiro- [fluorene-9,6'-indeno-(1,2-b)-fluorene-12',9''-fluorene] ((1,2-b)-DST-IF) have been synthesized by two different synthetic approaches. These terfluorenyl derivatives possess a different central indenofluorene core, namely (2,1-a)-indenofluorene or (1,2-b)-indenofluorene, which imposes two distinct geometry profiles, and different structural environments for the terfluorenyl fluorophores that translates into drastically different optical and electrochemical properties for (2,1-a)-DST-IF and (1,2-b)-DST-IF. These properties have been carefully studied through a combined experimental and theoretical approach. The (2,1-a)-DST-IF isomer has been successfully used as emitting layer in a blue single-layer small-molecule organic light-emitting diode (SMOLED) and appears as the first example of a blue emission arising from intramolecular terfluorenyl excimers. Regarding the importance of terfluorenyl derivatives in organic electronics, the present structure-properties relationship study, may open new avenues in the design of efficient blue fluorophores.
authors.affiliation: Université de Rennes 1-CNRS UMR 6226, Sciences Chimiques de Rennes-MaCSE group, Bat. 10 C, Campus de Beaulieu, 35042 Rennes Cedex, France. cyril.poriel@univ-rennes1.fr
authors.forename: Cyril
authors.initials: C
authors.lastname: Poriel
authors.forename: Joëlle
authors.initials: J
authors.lastname: Rault-Berthelot
authors.forename: Damien
authors.initials: D
authors.lastname: Thirion
authors.forename: Frédéric
authors.initials: F
authors.lastname: Barrière
authors.forename: Laurence
authors.initials: L
authors.lastname: Vignau