Circular Gold Nanodisks with Synthetically Tunable Diameters and Thicknesses

Abstract

Abstract2D or pseudo‐2D plasmonic Au nanocrystals, such as circular Au nanodisks, possess unique plasmonic properties. Circular Au nanodisks not only possess two large surfaces with circular symmetry but also exhibit the wide tunability for their plasmon resonance. However, the lack of effective synthetic methods for producing size‐tunable and monodispersed circular Au nanodisks hinders further studies on their properties and applications. Herein, the synthesis of uniformly sized circular Au nanodisks with synthetically tunable diameters and thicknesses is reported. By performing mild anisotropic oxidation on pregrown Au nanoplates with different thicknesses, the thicknesses of the obtained nanodisks are varied from ≈10 nm to ≈50 nm. The nanodisk diameters are tailored from ≈50 nm to ≈150 nm by controlling the oxidation time. Moreover, both homodimers and heterodimers made of circular Au nanodisks are constructed using molecular linkers. They exhibit rich plasmon modes. In particular, dark multipolar plasmon resonance modes can be excited and observed in the asymmetric heterodimers. Such circular Au nanodisks with controllable sizes, large atomically flat surfaces, and a dominant dipolar plasmon mode are ideal building blocks for constructing plasmonic assemblies and plasmon‐coupled systems with desired plasmonic properties and functions.

Continuous anisotropic growth of NIR-plasmonic CsxWO3-δ nanocrystals into rods and platelets

“…For the platelets, λsp-T of seeds at 1574 nm moderately redshifts and saturates near 1800 nm as AR decreases, while their λsp-L continuously blueshifts from 960 nm to 802 nm (Figure 3c). The trends of λsp-L and λsp-T, shifting in opposite directions during the growth of rods and platelets, is consistent with the LSPR behavior observed in gold nanorods and nanodisks [78][79][80][81] , as well as with the electrostatic approximation of the absorption behavior of anisotropic particles such as ellipsoids. 82 Meanwhile, the LSPR of dendritically grown platelets show a relatively small redshift of λsp-T (1465 nm à 1518 nm, Figure 3d) compared to that of non-dendritic platelets (1574 nm à 1812 nm, Figure 3c).…”

Single-Crystalline Gold Nanodisks on WS2 Mono- and Multilayers for Strong Coupling at Room Temperature

“…Moreover, in 2D TMDCs, the dipole moment of the exciton is strongly oriented in the plane of the 2D layer, which requires special attention when coupling to external fields. However, the dipolar LSPR mode of the nanodisk is oriented in the same plane as the excitons, thus, promoting a strong interaction . Finite-element and analytic calculations corroborate the observed resonance energy of the nanodisks even in the presence of a high-refractive index material, such as WS 2 , underneath (see Figure S4).…”

“…However, the dipolar LSPR mode of the nanodisk is oriented in the same plane as the excitons, thus, promoting a strong interaction. 38 Finite-element and analytic calculations corroborate the observed resonance energy of the nanodisks even in the presence of a high-refractive index material, such as WS 2 , underneath (see Figure S4). The inherent size distribution (with different radii) in a batch of gold nanodisks straighforwardly enables measurements on different nanodisks, with LSPRs distributed around the energy of the exciton (thereby allowing us to study the light−matter interaction at positive and negative detunings).…”

One Dimensional AuAg Nanostructures as Anodic Catalysts in the Ethylene Glycol Oxidation

“…A schematic presentation of the synthesis and product nanostructures is shown in Figure 2 below. nanoparticles [52][53][54]. The peaks noted at 370 and 500 nm have been previously reported for ultrathin AuAg NWs [46,55] and most likely correspond to the longitudinal and transverse modes of the structures due to the non-uniformity along their length [56,57].…”

“…Finally, aging at 40 • C proved to be critical as only large anisotropic disk-shaped nanoparticles of various shapes and sizes were formed (refer to Figure S5 for additional TEM images of products). The UV-vis analysis (Figure 1) of all the products from this study showed peaks at 500 and 370 nm in all cases except for the 40 • C aged sample, which displayed peaks at 525 and 780 nm, which is common for disk-like nanoparticles [52][53][54]. The peaks noted at 370 and 500 nm have been previously reported for ultrathin AuAg NWs [46,55] and most likely correspond to the longitudinal and transverse modes of the structures due to the non-uniformity along their length [56,57].…”