CC BY
6ALT'22
LASER DIAGNOSTICS AND SPECTROSCOPY
LD-I-6
Photomodification of Silver Nanocubes for Patch Plasmonic Nanoantennas by Visible Laser Light
S.G. Lukishova
Rochester, NY, USA lukishova@hotmail.com
From all types of plasmonic nanoantennas, the highest Purcell factor with increasing emitter radiative decay rate was obtained with metal plasmonic patch (gap) nanoantennas (a dielectric nanogap with emitters between a metal nanopar-ticle of a given shape (cube, triangle, etc.) and a metal film [1]. Silver nanoparticles, for instance, nanocubes [2-7] or their arrays [6] are used in patch nanoantennas for emitter fluorescence enhancement in visible spectral range [2-6] as well as for increasing stability and brightness of organic light emitting devices (OLEDs) [7]. We observed spontaneous intensity spikes up to ~400-900 kcounts/s, as well as a step-wise several times, increase in photoluminescence from silver nanocubes. Cw, 532 or 633 nm laser excitation was used (~100 ^W incident power with a 1.30 numerical aperture, oil immersion objective). These spontaneous spikes may influence the purity of single-photon emission from single emitters and even prevent photon antibunching. We investigated 100-nm silver nanocubes from nanoComposix protected by a few nanometer layers of polyvinylpyrrolidone (PVP), typically used in patch nanoantennas. Such spontaneous appearance of bright photoluminescence can be a result of photomodification of nanocube surface with formation over time of bright, few nanometer silver nanoclusters [8-10] on an oxidized surface of nanocubes. Confocal fluorescence microscopy micrographs showed appearance in time bright features with single-molecule behavior (stripes and semicircles in raster scans). These effects should be considered working with silver plasmonic nanostructures, especially under cw laser irradiation, see also [11,12].
[1] S.G. Lukishova and L.J. Bissell, "Nanophotonic advances for room-temperature single-photon sources", pp.103-178, in Quantum Photonics: Pioneering Advances and Emerging Applications, R.W. Boyd, S.G. Lukishova, V.N. Zadkov (Eds.), Springer (2019).
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[7] M.A. Fusella et al., "Plasmonic enhancement of stability and brightness in organic light-emitting devices", Nature 585, 37 (2020).
[8] LA. Peyser et al.,"Photoactivated fluorescence from individual silver nanoclusters", Science 291, 5501, 103 (2001).
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[10] C.D. Geddes et al., "Luminescent blinking from silver nanostructures", J. Phys. Chem. B 107, 9589 (2003).
[11] S.G. Lukishova, J. Brone, Z. Li, L. Young, "Photomodification of silver nanocubes for patch plasmonic nanoantennas by visible laser light", Book of Abstracts, the 51st Winter Colloquium on Physics of Quant. Electron., p. 154 (Snowbird, Utah, January 2022).
[12] S.G. Lukishova, J. Brone, D. Khan and Z. Li, "Ultrabright photoluminescence spikes and stepwise photoluminescence increase from colloidal silver nanoparticles for patch nanoantennas", J. Physics: Conf. Series. 2249, 012002 (2022).
