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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 28: Poster III
CPP 28.43: Poster
Wednesday, March 20, 2024, 11:30–13:30, Poster C
Influence of the Atmosphere on the Phosphorescence of a Brominated Diphenylphosphine Oxide–Ethyl Naphthaleneimide Dyad — Marvin Malchau1, Paul M. Reichstein2, Werner Reichstein3, and •Lothar Kador1 — 1University of Bayreuth, Institute of Physics and BIMF, 95440 Bayreuth, Germany — 2University of Bayreuth, Macromolecular Chemistry I and BIMF, 95440 Bayreuth, Germany — 3University of Bayreuth, Bayreuth Materials Center (BAYMAT), 95440 Bayreuth, Germany
The non-brominated diphenylphosphine-ethyl naphthaleneimide dyad (DPPENI) acts as a sensitive sensor for cumulative exposure to oxygen, since, under simultaneous irradiation of UV or blue light, the diphenylphosphine unit is oxidized to diphenylphosphine oxide; as a consequence, blue fluorescence emission is turned on in the originally non-fluorescing compound. [1] Upon bromination of the naphthaleneimide unit, strong phosphorescence is emitted in addition to the fluorescence. We studied the intensity and lifetime of the phosphorescence of the fully oxidized Br-DPPENI dyad in atmospheres of air, argon, helium, nitrogen, and oxygen as a function of pressure between vacuum and 1 bar. The experiment was performed in the frequency domain with a two-channel lock-in amplifier and the data were analyzed with the polar-plot or phasor technique. Reversible phosphorescence quenching due to triplet-triplet annihilation was found in the presence of atmospheric or pure oxygen, whereas the other gases had no effect.
[1] R. Shritz et al., Chem. Eur. J. 21, 11531 (2015).
Keywords: Phosphorescence Lifetime; Lock-in Amplifier; Polar-Plot Technique; Phasor