title: Donor/Acceptor Dihydroindeno[1,2-a]fluorene and Dihydroindeno[2,1-b]fluorene: Towards New Families of Organic Semiconductors.
abstract: New families of donor/acceptor semiconductors based on dihydroindeno[1,2-a]fluorene and dihydroindeno[2,1-b]fluorene are reported. Due to the spiro bridges, this new generation of dihydroindenofluorenes allows a spatial separation of HOMO and LUMO, which retains the high ET value of the dihydroindenofluorene backbone and excellent physical properties. This control of the electronic and physical properties has allowed a second generation of dihydroindeno[1,2-a]fluorene to be obtained with strongly enhanced performance in green and sky-blue phosphorescent organic light-emitting diodes (PhOLEDs) relative to the first generation of materials. To date, this is the highest performance ever reported for a blue PhOLED by using a dihydroindenofluorene derivative. Through this structure-property relationship study, a remarkable difference of performance between syn and anti isomers has also been highlighted. This surprising behaviour has been attributed to the different symmetry of the two molecules, and highlights the importance of the geometry profiles in the design of host materials for PhOLEDs.
authors.affiliation: UMR CNRS 6226, Institut des Sciences Chimiques de Rennes, Equipe Matière Condesnsée et Systèmes Electroactifs, Bât.10C, Campus de Beaulieu, 35042 Rennes Cedex (France).
authors.forename: Maxime
authors.initials: M
authors.lastname: Romain
authors.affiliation: UMR CNRS 7647, LPICM, Ècole Polytechnique, 91128 Palaiseau (France).
authors.forename: Denis
authors.initials: D
authors.lastname: Tondelier
authors.affiliation: UMR CNRS 7647, LPICM, Ècole Polytechnique, 91128 Palaiseau (France).|LICSEN/NIMBE UMR 3685, CEA Saclay, 91191 Gif Sur Yvette (France).
authors.forename: Bernard
authors.initials: B
authors.lastname: Geffroy
authors.affiliation: UMR CNRS 6226, Institut des Sciences Chimiques de Rennes, Equipe Matière Condesnsée et Systèmes Electroactifs, Bât.10C, Campus de Beaulieu, 35042 Rennes Cedex (France).
authors.forename: Olivier
authors.initials: O
authors.lastname: Jeannin
authors.affiliation: UMR CNRS 6164, Institut d'Electronique et des Télécommunications de Rennes, Département Microélectronique & Microcapteurs, Université de Rennes 1, Bât.11B, Campus de Beaulieu 35042, Rennes Cedex (France).
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Jacques
authors.affiliation: UMR CNRS 6226, Institut des Sciences Chimiques de Rennes, Equipe Matière Condesnsée et Systèmes Electroactifs, Bât.10C, Campus de Beaulieu, 35042 Rennes Cedex (France).
authors.forename: Joëlle
authors.initials: J
authors.lastname: Rault-Berthelot
authors.affiliation: UMR CNRS 6226, Institut des Sciences Chimiques de Rennes, Equipe Matière Condesnsée et Systèmes Electroactifs, Bât.10C, Campus de Beaulieu, 35042 Rennes Cedex (France). cyril.poriel@univ-rennes1.fr.
authors.forename: Cyril
authors.initials: C
authors.lastname: Poriel
keywords: donor-acceptor systems; fluorenes; organic light-emitting diodes; phosphorescence; structure-property relationships