Precise control over the morphology of nanostructures is critical for tailoring their physical and chemical properties. This study addresses the challenge of developing a simple, integrated method for synthesizing both 1D and 2D colloidal Cu nanostructures in a single system, achieving successful tuning of their localized surface plasmon resonance (LSPR) properties. A facile hydrothermal synthesis utilizing potassium iodide (KI) and hexadecylamine (HDA) is presented for controlling Cu nanostructure morphologies. The key to achieving 1D nanowires (NWs) and 2D nanoplates (NPs) depends on the controlled adsorption of HDA molecules and iodide (I-) ions on specific crystal facets. Depending on the morphologies, the resultant Cu nanostructures exhibit tunable LSPR peaks from 558 nm [nanoplates (NPs)] to 590 nm [nanowires (NWs)]. These results pave the way for the scalable and cost-effective production of plasmonic Cu nanostructures with tunable optical properties, holding promise for applications in sensing, catalysis, and photonic devices.

Citations

• Complexation-controlled Cu@Ag core-shell flakes for thermally stable printed electrodes in flexible energy-storage capacitors
  Seokhwan Kim, Geumseong Lee, Ye Chan Lee, Je-Hui Koo, Seonhwa Park, Geon-Tae Hwang, Mahesh Peddigari, Jungho Ryu, Dahye Shin, Kyoung Jin Jung, Kwi-Il Park, Yuho Min
  Chemical Engineering Journal.2026; 540: 177341.     CrossRef

We present the structural and optical properties of Au@TiO₂ core-shell microsphere structure prepared by a hydrothermal synthesis method. As a way to improve the efficiency of organic solar cells, the Au@TiO₂ core-shell microsphere was synthesized to use the local surface plasmon resonance (LSPR) phenomenon. The synthesized results were confirmed to have the Au@TiO₂ core-shell structure using a high-resolution transmission electron microscopy. An absorption was observed to occur at 527 nm belonging to the visible light region using a visible light spectroscopy, which supports the LSPR phenomenon. We suggest that the Au@TiO₂ core-shell microsphere is highly likely to be applied to organic solar cells including dye-sensitized solar cells. In addition, we expect it to be widely used not only in the energy but also in the bio as well as in the environmental fields.

In this study, e-beam equipment was used to form silver nanoparticles on thin films of TiO₂ to increase the efficiency of dye-sensitized solar cells and improve the annealing process. TiO₂ thin films with nanoparticle photoelectrodes were fabricated in individual units for use in dye-sensitized solar cells. The characteristics of dye-sensitized solar cells were compared to those of the prepared TiO₂ photoelectrode with and without nanoparticles. The dye-sensitized solar cells with silver nanoparticles showed a significant increase in the electric current density compared with the pure TiO₂ dye-sensitized solar cell and improved the solar conversion efficiency to 27.89%. The increased density of electric current increased the extent of light absorption of the dye owing to the plasmon resonance of the nanoparticles at the local surfaces. This phenomenon led to increased light scattering, which in turn increased the current density of the dye-sensitized solar cells and improved the solar conversion efficiency.

We proposed and demonstrated the double layered metallic nano-hole structure using polystyrene beads process to enhance the sensitivity of surface plasmon resonance (SPR). The double layered SPR structures are calculated using the finite-difference time-domain (FDTD) method for the width, thickness, and period of the metallic nano-hole structures. The thickness of the metal film and the metallic nano-hole is 30 and 20 nm in the 214 nm wide nano-hole size, respectively. The double layered SPR structures are fabricated with monolayer polystyrene beads of 420 nm wide. The sensitivities of the conventional SPR sensor and the double layered SPR sensor are obtained to 42.2 and 52.1 degree/RIU, respectively.

We have investigated the optical properties of plamonic waveguide with tapered structure based on InP material for photonic integrated circuit(PIC). The proposed plasmonic waveguide is covered with the Ag thin film to generate the plasmonic wave on metallic interface. The optical characteristics of plasmonic waveguide were calculated using the three-dimensional finite-difference time-domain method. The plasmonic waveguide was fabricated with the lengths of 2 to 10 μm and the widths of 400 to 700 nm, respectively. The plasmonic mode and optical loss were measured. The optimum plasmonic length is 10 μm and widths are 600 and 700 nm in the fabricated waveguide. This plasmonic waveguide can be directly integrated with other conventional optical devices and can be essential building blocks of PIC.

In this paper, we have theoretically analyzed and designed a dielectric multi-layer sensor with a SPR (surface plasmon resonance) using analytical calculation and FDTD (finite difference time-domain) methods. The proposed structure is composed of periodic layer and thin metal film. It has many advantages. One of that is a high sensitivity of the SPR. Another is a high Q-factor of the characteristics in the PhC (photonic crystals) micro-cavity structure. The incident light has double resonance characteristics, because the filtered light by PhC structure, dielectric multi-layer, is met the thin metal film for SPR effect. We have also observed the change of resonance characteristics according to the variation of effective index on the metal film.