Paramagnetic defect centres in crystalline Alq3
| Autor: | C Ghica, Markus Schwoerer, M N Grecu, Anisoara Mirea, M Cölle |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Chemistry
Annealing (metallurgy) chemistry.chemical_element Condensed Matter Physics law.invention Condensed Matter::Materials Science Crystallography Paramagnetism Electron diffraction Transmission electron microscopy law Aluminium General Materials Science Sublimation (phase transition) Triplet state Electron paramagnetic resonance |
| Zdroj: | Journal of Physics: Condensed Matter. 17:6271-6283 |
| ISSN: | 1361-648X 0953-8984 |
| DOI: | 10.1088/0953-8984/17/39/012 |
| Popis: | X- and Q-band electron paramagnetic resonance (EPR) investigation of different crystalline Alq 3 (tris(8-hydroxyquinoline)aluminium (III)) fractions formed by a train sublimation method are reported. Several paramagnetic defect centres corresponding to 1/2, 1, and 3/2 spin are observed at room temperature. Their intensity is dependent on the temperature, nature of the crystalline phase, and preparation conditions. Spectra simulation and analysis based on the spin Hamiltonian appropriate to a high spin system (S ≥ 1) suggest the existence of randomly oriented triplets and quartets in annealed Alq 3 fractions. The crystalline Alq 3 phases responsible for the EPR powder spectra have been identified by transmission electron microscopy measurements performed on these sample fractions. |
| Databáze: | OpenAIRE |
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