We demonstrate the capability of DNA self-assembled optical antennas to direct the emission of an individual fluorophore, which is free to rotate. DNA origami is used to fabricate optical antennas composed of two colloidal gold nanoparticles separated by a predefined gap and to place a single Cy5 fluorophore near the gap center. Although the fluorophore is able to rotate, its excitation and far-field emission is mediated by the antenna, with the emission directionality following a dipolar pattern according to the antenna main resonant mode. This work is intended to set out the basis for manipulating the emission pattern of single molecules with self-assembled optical antennas based on colloidal nanoparticles.
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http://dx.doi.org/10.1021/acs.nanolett.9b02886 | DOI Listing |
Phys Rev Lett
December 2024
Center of Single-Molecule Sciences, Institute of Modern Optics, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University, Tianjin 300350, China.
Via conductance measurements of thousands of single-molecule junctions, we report that the π-π coupling between neighboring aromatic molecules can be manipulated by laser illumination. We reveal that this optical manipulation originates from the optical plasmonic gradient force generated inside the nanogaps, in which the gapped antenna electrodes act as optical tweezers pushing the neighboring molecules closer together. These findings offer a nondestructive approach to regulate the interaction of the molecules, deepening the understanding of the mechanism of π-π interaction, and open an avenue to manipulate the relative position of extremely small objects down to the scale of single molecules.
View Article and Find Full Text PDFACS Nano
December 2024
Department of Physics of Information in Matter and Center for Nanophotonics, NWO-I Institute AMOLF, Science Park 104, NL 1098XG Amsterdam, The Netherlands.
Phosphor-converted micro-light emitting diodes (micro-LEDs) are a crucial technology for display applications but face significant challenges in light extraction because of the high refractive index of the blue pump die chip. In this study, we design and experimentally demonstrate a nanophotonic approach that overcomes this issue, achieving up to a 3-fold increase in light extraction efficiency. Our approach involves engineering the local density of optical states (LDOS) to generate quasi-guided modes within the phosphor layer by strategically inserting a thin low-index spacer in combination with a metasurface for mode extraction.
View Article and Find Full Text PDFSci Adv
December 2024
Nano-Cybernetic Biotrek, Media Lab, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Monitoring electrical potentials with high recording site density and micrometer spatial resolution in liquid is critical in biosensing. Organic electronic materials have driven remarkable advances in the field because of their unique material properties, yet limitations in spatial resolution and recording density remain. Here, we introduce organic electro-scattering antennas (OCEANs) for wireless, light-based probing of electrical signals with micrometer spatial resolution, potentially from thousands of sites.
View Article and Find Full Text PDFSensors (Basel)
November 2024
College of Electronics and Information Engineering, Shenzhen University, Shenzhen 518060, China.
In this paper, a novel topology and method for designing a multi-band rectenna is proposed to improve its RF-DC efficiency. The rectifier achieves simultaneous rectification using both series and parallel configurations by connecting two branches to the respective terminals of the diode, directing the energy input from two ports to the anode and cathode of the diode. Six desired operating frequency bands are evenly distributed across these two branches, each of which is connected to antennas corresponding to their specific operating frequencies, serving as the receiving end of the system.
View Article and Find Full Text PDFMolecules
December 2024
Dipartimento di Scienze Chimiche e Geologiche, Università di Cagliari, Complesso Universitario di Monserrato, S.P. 8 Km 0.700, I-09042 Monserrato, Italy.
By combining Er and Yb ions with 3,6-dithiophene-anilate (ThAn) and scorpionate hydrotris(pyrazol-1-yl)borate (HBpz) ligands new luminescent dinuclear complexes are obtained. The two materials formulated as [((HB(pz))Yb)(μ-thAn)]·4DCM·1.3HO and [((HB(pz))Er)(μ-thAn)]·4DCM·1.
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