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Plasmonic solid‐state nanopores with tunable hole diameters can be prepared via a photocatalytic effect resulting from the enhanced electromagnetic (EM) field inside a metallic ring on top of a dielectric nanotube. Under white light illumination, the plasmon‐enhanced EM‐field induces a site‐selective metal nucleation and growth within the ring. This approach is used to prepare Au and bimetallic Au–Ag nano‐rings and demonstrate the reduction of the initial inner diameter of the nanopore down to 4 nm. The tunability of the nanopore diameter can be used to enable optimized detection of single entities with different sizes. As a proof‐of‐concept, single object detection of double stranded DNA (dsDNA) and Au nanoparticles (AuNPs) with a diameter down to 15 nm is performed. Numerical simulations provide insights into the EM‐field distribution and confinement, showing that a field intensity enhancement of up to 104 can be achieved inside the nanopores. This localized EM‐field can be used to perform enhanced optical measurements and generate local heating, thereby modifying the properties of the nanopore. Such a flexible approach also represents a valuable tool to investigate plasmon‐driven photochemical reactions, and it can represent an important step toward the realization of new plasmonic devices. [ABSTRACT FROM AUTHOR]

Control over multiple optical elements that can be dynamically rearranged to yield substantial three‐dimensional structural transformations is of great importance to realize reconfigurable plasmonic nanoarchitectures with sensitive and distinct optical feedback. In this work, we demonstrate a transformable plasmonic helix system, in which multiple gold nanoparticles (AuNPs) can be directly transported by DNA swingarms to target positions without undergoing consecutive stepwise movements. The swingarms allow for programmable AuNP translocations in large leaps within plasmonic nanoarchitectures, giving rise to tailored circular dichroism spectra. Our work provides an instructive bottom‐up solution to building complex dynamic plasmonic systems, which can exhibit prominent optical responses through cooperative rearrangements of the constituent optical elements with high fidelity and programmability. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman spectroscopy is a popular tool for the detection of extremely small quantities of target molecules. Au nanoparticles have been very successful in this respect due to local enhancement of the light intensity caused by their plasmon resonance. Furthermore, Au nanoparticles are biocompatible, and target substances can be easily attached to their surface. Here, we demonstrate that Au-decorated CdSe nanowires when employed as SERS substrates lead to an enhancement as large as 10 with respect to the flat Au surfaces. In the case of hybrid metal-CdSe nanowires, the Au nucleates preferably on lattice defects at the lateral facets of the nanowires, which leads to a homogeneous distribution of Au nanoparticles on the nanowire, and to an efficient quenching of the nanowire luminescence. Moreover, the size of the Au nanoparticles can be well controlled via the AuCl concentration in the fabrication process. We demonstrate the effectiveness of our SERS substrates with two target substances, namely, cresyl-violet and rhodamine-6G. Au-decorated nanowires can be easily fabricated in large quantities at low cost by wet-chemical synthesis. Furthermore, their deposition onto various substrates, as well as the functionalization of these wires with the target substances, is as straightforward as with the traditional markers. [ABSTRACT FROM AUTHOR]

CdSe-Au networks were synthesized by a colloidal chemistry technique. They entail CdSe nanorods with a diameter of ~10 nm and a length of ~40 nm, which are joined together by Au domains (~5 nm). Individual networks were positioned by AC dielectrophoresis between bow-tie electrodes with a gap of ~100 nm and their conductivity as well as the photoelectrical properties were investigated. Nanorod networks, with multiple Au domains on the nanorod surface, displayed stable conductivity that was not sensitive to blue laser light illumination. Such nanostructures were transformed by thermal annealing to networks with Au domains only at the nanorod tips. In this system, the overall conductivity was reduced, but a clear photocurrent signal could be detected, manifesting semiconductor behavior. [ABSTRACT FROM AUTHOR]