title: Structural organization of pi conjugated highly luminescent molecular material.
abstract: We report on striking evidence for a room temperature structural phase instability in p-hexaphenyl, inducing a nonplanar conformation of the molecules. Solid state proton NMR and single crystal x-ray diffraction allow the analysis of the organization, the individual dynamics and the involved symmetry breaking. The analysis of Raman spectra above and below room temperature reveals a singular behavior suggesting a modification of the overlap between the electronic wave function induced by the nonplanarity. These results provide a new basis to answer fundamental issues related to molecular and electronic materials and, in particular, luminescent organic devices.
authors.affiliation: Groupe Matière Condensée et Matériaux, UMR CNRS 6626, Université de Rennes I, 35042 Rennes, France.
authors.forename: B
authors.initials: B
authors.lastname: Toudic
authors.forename: P
authors.initials: P
authors.lastname: Limelette
authors.forename: G
authors.initials: G
authors.lastname: Froyer
authors.forename: F
authors.initials: F
authors.lastname: Le Gac
authors.forename: A
authors.initials: A
authors.lastname: Moréac
authors.forename: P
authors.initials: P
authors.lastname: Rabiller