Dresden 2017 – scientific programme

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DS: Fachverband Dünne Schichten

DS 50: Optics and Light-Matter Interaction with Excitons in 2D Materials
(Joint Session HL, DS, O, and TT, organized by DS)

DS 50.2: Talk

Friday, March 24, 2017, 11:30–11:45, CHE 89

Spectral Focusing of Broadband Silver Electroluminescence in Nanoscopic FRET-LEDs — •Robin Puchert, Florian Steiner, Gerd Plechinger, Felix Hofmann, Christian Schüller, Tobias Korn, Jan Vogelsang, Sebastian Bange, and John Lupton — Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany

A challenge in LED technology is the use of fluorescence resonance energy transfer (FRET) in spectral conversion. An LED based on FRET effect would show both up- and down-conversion of electroluminescence (EL), since the electrically driven resonance of the light emitting device (donor) couples non-radiatively to the acceptor fluorophore resonance.

FRET-LEDs have already been proposed. However, such devices have yet to be demonstrated. The challenge lies in generating light electrically in close proximity to a dipolar acceptor in order to allow near-field coupling. We present a solution to this problem by combining a lateral LED structure with a two-dimensional transition-metal dichalcogenide overlayer (TMDC). The LED's entire excitation energy is transferred to the 2D crystal overlayer through resonant dipole-dipole coupling rather than by trivial reabsorption. This is quite remarkable given the fact that such an atomically thin TMDC monolayer absorbs only a mere 4 % of light. By using plasmonic silver nanoparticle junctions to generate broad-band EL coming from sub-diffraction localized hotspots, we see dramatic spectral focusing of the EL into the narrow excitonic resonance of the atomically thin overlayer.