Dokument: Time-Resolved Spectroscopy on Copper(I) Carbene Complexes
| Titel: | Time-Resolved Spectroscopy on Copper(I) Carbene Complexes | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=63186 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20230719-154105-3 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Englisch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | Nolden, Oliver [Autor] | |||||||
| Dateien: |
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| Beitragende: | Prof. Dr. Gilch, Peter [Gutachter] Prof. Dr. Christian Ganter [Gutachter] | |||||||
| Dewey Dezimal-Klassifikation: | 500 Naturwissenschaften und Mathematik » 540 Chemie | |||||||
| Beschreibung: | Organic light-emitting diodes (OLEDs) are an emerging technology that have attracted significant attention due to their prominent use in displays and other lighting applications. The development of efficient OLEDs requires the identification and optimization of suitable emitter materials that can generate bright light in a range of colors. Copper(I) carbene complexes have been suggested as promising candidates for OLED emitters due to their unique photophysical properties. In this thesis, two copper(I) carbene complexes are investigated using a range of spectroscopic methods, first and foremost time-resolved techniques, to explore their potential as OLED emitters and to deepen the understanding of their photophysics.
The first study explores the photophysics of a linearly coordinated copper(I) carbene complex, namely, [1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene] (2-picoline) copper(I) tetrafluoroborate (NHCCuPy). Previous studies showed that the emission characteristics of the compound strongly depend on the environment. Here, these observations are picked up, and conclusive results are drawn on the compound's structure and photophysics in solution. For a systematic approach, solvents are chosen as coordinating and non-coordinating. In coordinating solvents evidence is obtained for an equilibrium reaction between solvent and solute forming a trigonal complex with distinct absorption, emission, and excited state kinetic behavior. In contrast, in non-coordinating solvents, the results indicate that the linear species, also present in single crystals, constitutes the dominant species. Its excited state kinetics is successfully deciphered by time-resolved experiments and quantum chemical computations In the second study, a similar copper(I) carbene complex, in which the 2-picoline ligand is replaced by a chelating dibenzoylmethanoate ligand (1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene](dibenzoylmethanoate)copper(I), abbreviated: NHCCuDBM) is investigated. Here, it is systematically elaborated on whether or not this trigonal complex exhibits a suitable emission behavior and why. First, the ligand dibenzoylmethanoate and its protonated form dibenzoylmethane are examined in detail. The latter shows a high radiative rate constant for its lowest excited singlet state. However, this state is efficiently quenched due to isomerization processes occurring in the excited state. These processes are absent in the complex and the overall excited state lifetime is extended by roughly two orders of magnitude. Despite this prolongation of the excited state lifetime, also the complex is virtually non-emissive. This behavior is clarified by the character and energetic order of the lowest excited states. In contrast to the free DBM, where the lowest excited state is of ππ* character, in the complex the lowest excited state constitutes a state dominantly of nπ* character with a typically small oscillator strength. Considering spectroscopic results and quantum chemical calculations, a comprehensive picture of the compound's excited state kinetics is obtained. Significant population of a triplet state is considered unlikely. Based on these results, structural suggestions are made to enable the complexes' emission. Furthermore, a connection is drawn to the peculiar environmental dependence addressed in the first study. | |||||||
| Lizenz: |  Dieses Werk ist lizenziert unter einer Creative Commons Namensnennung 4.0 International Lizenz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät » WE Chemie » Physikalische Chemie und Elektrochemie | |||||||
| Dokument erstellt am: | 19.07.2023 | |||||||
| Dateien geändert am: | 19.07.2023 | |||||||
| Promotionsantrag am: | 16.05.2023 | |||||||
| Datum der Promotion: | 30.06.2023 |
