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Investigation of photoluminescence properties of 2D-nanoparticles to be used as fluorescence markers in microscopy

: Kuppadakkath, A.; Knopf, H.; Bucher, T.; Staude, I.; Pertsch, T.; Eilenberger, F.


Institute of Electrical and Electronics Engineers -IEEE-:
Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference, CLEO/Europe-EQEC 2019 : 23-27 June 2019, Munich, Germany
Piscataway, NJ: IEEE, 2019
ISBN: 978-1-7281-0469-0
ISBN: 978-1-7281-0470-6
Conference on Lasers and Electro-Optics Europe (CLEO Europe) <2019, Munich>
European Quantum Electronics Conference (EQEC) <2019, Munich>
Conference Paper
Fraunhofer IOF ()

Summary form only given. Transition metal dichalcogenides (TMDs) are direct bandgap semiconductors [1], and they exhibit fascinating optical properties, such as valley polarization, room temperature excitons, and high optical nonlinearity. Single and few-layer TMDs and TMD-nanoparticles exhibit much stronger photoluminescence than the bulk material [2]. This property makes them an attractive candidate for use as mesoscale fluorescent markers, e.g., for use in fluorescence microscopy. As opposed to conventional fluorescent markers, such as fluorescent molecules they do not exhibit phototoxicity and have been shown to be biocompatible in contrast to, e.g., many types of quantum dots. Here we focus on the characterization of MoS 2 and WS 2 nanoparticles, obtained through liquid phase exfoliation, from powdered precursors. Sonication of TMD powder in N-Methyl pyrrolidone (NMP) is carried out, as NMP and single layer TMDs have comparable surface energies to prevent the restacking of exfoliated nanosheets. The resulting solution was found to have particles of a typical size of 65 nm, which have been investigated for PL-spectra and long-term PL-behaviour, such as blinking and bleaching. Structural analysis reveals that we have a mixture of particles and particle agglomerates. PL spectra show that both exhibit comparable spectral signatures with peak wavelengths ranging from 600 to 640nm. The excitation wavelength was 532nm. We find that these results indicate, that TMD-nanoparticles are suitable, e.g., for use as fluorescent guide stars in adaptive optical microscopy in inhomogeneous samples, e.g., tissue. 2D-nanoparticles would be infiltrated into the sample, and the PL-emission could be used by a combination of a wavefront-sensor and an adaptive optical element to undo the effects of scattering in the vicinity of the particle. This method would leverage the strong PL, biocompatibility and long-term stability of the 2D-nanoparticles, to allow for longer observation cycles in sensitive samples, such as living tissue.