Filtern
Dokumenttyp
- Vortrag (43) (entfernen)
Sprache
- Englisch (23)
- Deutsch (19)
- Mehrsprachig (1)
Referierte Publikation
- nein (43)
Schlagworte
- Nano (43) (entfernen)
Organisationseinheit der BAM
- 1 Analytische Chemie; Referenzmaterialien (19)
- 1.2 Biophotonik (19)
- 4 Material und Umwelt (18)
- 4.2 Material-Mikrobiom Wechselwirkungen (18)
- 5 Werkstofftechnik (4)
- 5.4 Multimateriale Fertigungsprozesse (4)
- 6 Materialchemie (4)
- 6.1 Oberflächen- und Dünnschichtanalyse (3)
- 6.3 Strukturanalytik (1)
- 6.5 Synthese und Streuverfahren nanostrukturierter Materialien (1)
Eingeladener Vortrag
- nein (43)
In recent years, chromium (III) complexes have received a lot of attention as novel near-infrared (NIR) emitters triggered by the report on the first molecular ruby Cr(ddpd)2(BF4)3 with a high photoluminescence quantum yield of 13.7% of its near infrared (NIR) emission band and a long luminescence lifetime of 1.122 ms at room temperature.[1] However, in an oxygen-containing environment, the photoluminescence quantum yields and luminescence lifetimes of these chromium(III) complexes show only very small values. This hampers their application as NIR luminescence labels. This application, that cannot be tackled by conventional deoxygenating approaches, requires suitable strategies to protect the luminescence of the chromium(III) complexes from oxygen quenching. An elegant approach to reduce the undesired luminescence quenching by triplet oxygen explored by us presents the incorporation of these chromium(III) complexes into different types of amorphous, non-porous silica nanoparticles, that can be simply surface functionalized, e.g., with targeting ligands and/or other sensor molecules. In this work, as first proof-of-concept experiments, a set of chromium (III) complexes constituting of different ligands and counter anions, were embedded into the core of silica nanoparticles. Subsequently, the optical properties of the resulting luminescent silica nanoparticles were spectroscopically assessed by steady state and time-resolved luminescence spectroscopy. First results of time-resolved luminescence measurements confirm our design concept of nanoscale NIR emissive Cr(III) complex-based reporters
Luminescent Nanoparticles – From Photophysics to the Measurement of Photoluminescence Quantum Yields
(2023)
Inorganic nanocrystals with linear and nonlinear photoluminescence in the ultraviolet, visible, near infrared and short-wave infrared like spectrally shifting lanthanide-based nanoparticles (LnNCs) like NaYF4: Yb, Er and semiconductor quantum dots have meanwhile found applications in the life and material sciences ranging from optical reporters for bioimaging and sensing over security barcodes to solid state lighting and photovoltaics. The identification of optimum particle architectures for photonic applications requires quantitative spectroscopic studies, ideally flanked by single particle studies to assess spectroscopic inhomogeneities on a particle-to-particle level for typical preparation methods. In the following, photoluminescence studies of LnNCs are presented, addressing parameters such as particle size, surface coating, and dopant ion concentration as well as excitation power density mandatory for a profound mechanistic understanding of the nonradiative deactivation pathways in these nanocrystals. In addition, methods for the determination of particle brightness and photoluminescence quantum yield in different spectral windows are presented.