Molecular crystals and liquid crystals science technology. Section A, Molecular crystals and liquid crystals/Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals · 1998 · 14 citations · 10 references
Natural SciencesChemistryPhysicsMolecular PhysicsSolid-state ChemistrySpectroscopyElectronic Excited StatesFluorescence SpectroscopyLiquid CrystalsMolecular Excited StatesOptical Properties Of SolidsUltrafast OpticsExcited-state DynamicsFluorescence LifetimeFluorescence Lifetime MeasurementsPhase Transition DynamicsPicosecond SpectroscopyTemperature DependenceTime-resolved Fluorescence SpectroscopyTransient Fluorescence Spectroscopy
Abstract Fluorescence properties of azobenzene liquid crystal, 4,4′-dioctyloxy- azobenzene, were examined by steady-state and picosecond single-photon timing spectroscopy. It was found that the fluorescence from azobenzene aggregate with a peak at ∼ 630 nm was observed in the solid phase in addition to the very weak S2 fluorescence from azobenzene monomer centered at 420 nm. The fluorescence lifetimes of both aggregate and monomer S2 state were estimated to be approximately 150 ps and shorter than 2 ps. The relationship between the excited-state dynamics of azobenzene liquid crystal and its phase transition was analyzed on the basis of the temperature dependence of relative fluorescence intensity and fluorescence lifetime of aggregate.
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