Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 29: Poster: 2D Materials
O 29.11: Poster
Dienstag, 19. März 2024, 12:30–14:30, Poster A
Photoluminescence upconversion in monolayer WSe2 activated by plasmonic cavities through resonant excitation of dark excitons — •Niclas S. Mueller1,2, Rakesh Arul1, Gyeongwon Kang1, Ashley P. Saunders3, Amalya C. Johnson3, Ana Sánchez-Iglesias4, Shu Hu1, Lukas A. Jakob1, Jonathan Bar-David1, Bart de Nijs1, Luis M. Liz-Marzán4, Fang Liu3, and Jeremy J. Baumberg1 — 1NanoPhotonics Centre, University of Cambridge, UK — 2Present address: Fritz Haber Institute of the Max Planck Society Berlin, Germany — 3Department of Chemistry, Stanford University, USA — 4CIC biomaGUNE, Donostia-San Sebastián, Spain
Anti-Stokes photoluminescence (PL) is light emission at a higher photon energy than the excitation, with applications in optical cooling, lasing, and the detection of infrared light. Here, we show how plasmonic nano-cavities activate anti-Stokes PL in WSe2 monolayers through resonant excitation of a dark exciton at room temperature. The optical near-fields of the plasmonic cavities excite the out-of-plane transition dipole of the dark exciton, leading to light emission from the bright exciton at higher energy. Through statistical measurements on hundreds of plasmonic cavities, we show that coupling to the dark exciton leads to a near hundred-fold enhancement of the upconverted PL intensity. We further demonstrate a selective and reversible switching of the upconverted PL via electrochemical gating.
[1] Mueller et al. Nat. Commun. 14, 5726 (2023)
Keywords: WSe2; dark exciton; upconversion; plasmonics; photoluminescence