Erlangen 2018 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 54: Nano-Optics (Single Quantum Emitters and Plasmonics)
Q 54.9: Vortrag
Donnerstag, 8. März 2018, 12:30–12:45, K 0.023
Measuring Quantum Yield of Organic Dyes by Lifetime Modifications Using a Metal Ball — •Ersan Özelci1,3, Ute Resch-Genger2,3, and Oliver Benson1,3 — 1Humboldt-Universität zu Berlin — 2Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin — 3School of Analytical Sciences Adlershof (SALSA), Berlin
A key parameter for all fluorescence applications presents the photoluminescence quantum yield which can be determined by optical methods either relatively compared to a fluorescence quantum yield standard with known QY or absolutely with e.g., integrating sphere spectroscopy [1]. An interesting alternative, that can be even extended to single emitters, presents the so-called silver ball method which utilizes the modification of the spontaneous emission of dyes in the neighborhood of metallic surface [2,3].
In our experiment, the silver coated spherical ball is placed on PMMA coated glass substrate. Then, confocal fluorescence lifetime imaging (FLIM) microscope is performed using scanning piezo stage. FLIM maps with concentric rings centered with respect to the contact point of the sphere are obtained. The variation of the fluorescence lifetime as a function of the molecule to sphere distance are extracted from the FLIM map. We fitted the data to theoretical curves and derived the QY. We will discuss planned experiments towards an integration of our approach with microfluidics setups.
[1] C. Würth et al., Nat Protocols 2013.
[2] K.Drexhage et al, J.Lumin, 1-2, 693 (1970).
[3] Lunnemann et al, ACS Nano 2013, 5984-5992.