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Projekt Druckansicht

Effiziente thermisch aktivierte verzögerte Fluoreszenz in endohedralen Metallofullerenen

Antragsteller Dr. Alexey A. Popov
Fachliche Zuordnung Physikalische Chemie von Molekülen, Flüssigkeiten und Grenzflächen, Biophysikalische Chemie
Förderung Förderung von 2019 bis 2023
Projektkennung Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 421793592
 
Erstellungsjahr 2023

Zusammenfassung der Projektergebnisse

The project was aimed at the advanced understanding of photoluminescent properties of metallofullerenes, including the influence of the composition of endohedral species on the photophysical properties. Particular focus was the phenomenon of thermally-activated delayed fluorescence discovered in fullerene Y3N@C80. We performed comprehensive variable-temperature, steady-state and timeresolved studies of luminescence in a series of metallofullerenes, such as YxSc3–xN@C80, chemical derivatives of Y3N@C80 with different addition motifs, and Nd-based metallofullerenes. In the series of YxSc3–xN@C80 compounds, we found a strong variation of the emission energy depending on the cluster composition. The more Sc atoms are present in the cluster, the further into near-infrared range its emission is shifted. Likewise, the energy difference between singlet and triplet excited state, and luminescence lifetimes decreased when ore Sc atoms were present. These changes were interpreted by the phenomenon of the photo-switching, in which position of the cluster inside the fullerene changed after photon absorption. The studies of the triplet state by light-induced electron paramagnetic resonance spectroscopy allowed to understand how spin density is distributed between the fullerene and metal atoms. Another important finding of the project was the first observation of Nd-based luminescence in Nd metallofullerenes, NdSc2N@C80, NdLu2N@C80, and NdY2N@C80. We found that the internal strain experienced by the NdM2N cluster inside the fullerene caused a strong nephelauxetic effect, indicating that degree of covalency in Nd bonding is unusually high. At the same time, the spectra exhibited fine structure of the emission bands, evidencing the unprecedentedly strong ligand-field splitting.

Projektbezogene Publikationen (Auswahl)

 
 

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