Berlin 2018 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 46: Poster Session IV

CPP 46.50: Poster

Mittwoch, 14. März 2018, 11:00–13:00, Poster A

Phosphorescence Lifetime of a Brominated Diphenylphosphine-Alkyl Naphthaleneimide Luminescence Turn-On Dyad in Different Atmospheres — Sebastian Feulner¹, •Lothar Kador¹, Paul M. Reichstein², and Werner Reichstein³ — ¹University of Bayreuth, Institute of Physics, 95440 Bayreuth, Germany — ²University of Bayreuth, Macromolecular Chemistry I, 95440 Bayreuth, Germany — ³University of Bayreuth, Bayreuth Materials Center (BAYMAT), 95440 Bayreuth, Germany

We have studied a brominated diphenylphosphine-alkyl naphthaleneimide luminescence turn-on dyad which, in its oxidized form, emits strong fluorescence and moderate phosphorescence when excited with UV light at 365 nm. In ambient air, the phosphorescence is partly quenched by triplet-triplet annihilation (TTA) with molecular oxygen. At lower pressure, TTA is reduced and, therefore, the contribution of the phosphorescence to the total luminescence and the phosphorescence lifetime increase. The phosphorescence signal and the phosphorescence lifetime were studied in the frequency domain with modulated UV excitation at air pressures between 1 bar and vacuum. Both quantities increase strongly below 100 mbar. The phosphorescence was also investigated in pure oxygen and pure argon atmosphere at 1 bar. As expected, oxygen causes slightly stronger phosphorescence quenching than air. Surprisingly, in argon the phosphorescence is significantly weaker than in vacuum. The experimental data are interpreted in the so-called polar-plot (or Cole-Cole plot) representation.