The localized surface plasmon resonance (LSPR) of oxide-free Cu nanoparticles fabricated by nanosphere lithography is examined by UV−vis extinction spectroscopy and electrodynamics theory. The LSPR of the Cu nanoparticles is significantly affected by the presence of copper oxides and the removal of the oxide species yields a dramatic difference in the observed LSPR. From a comparison of the LSPR of Cu, Ag, and Au nanoparticles of similar geometry, we conclude that Cu displays an intense and narrow LSPR peak that is comparable to Ag and Au.

The effect of diffractive coupling on the collective plasmon line shape of linear arrays of Ag nanoparticles fabricated by electron beam lithography has been investigated using Rayleigh scattering spectroscopy. The array spectra exhibit an intricate multi-peak structure, including a narrow mode that gains strength for interparticle distances that are close to the single particle resonance wavelength. A version of the discrete dipole approximation method provides an excellent qualitative description of the observed behavior.

Researchers and industrialists have taken advantage of the unusual optical, magnetic, electronic, catalytic, and mechanical properties of nanomaterials. Nanoparticles and nanoscale materials have proven to be useful for biological uses. Nanoscale materials hold a particular interest to those in the biological sciences because they are on the same size scale as biological macromolecules, proteins and nucleic acids. The interactions between biomolecules and nanomaterials have formed the basis for a number of applications including detection, biosensing, cellular and in situ hybridisation labelling, cell tagging and sorting, point-of-care diagnostics, kinetic and binding studies, imaging enhancers, and even as potential therapeutic agents. Noble metal nanoparticles are especially interesting because of their unusual optical properties which arise from their ability to support surface plasmons. In this review the authors focus on biological applications and technologies that utilise two types of related plasmonic phenomonae: localised surface plasmon resonance (LSPR) spectroscopy and surface-enhanced Raman spectroscopy (SERS). The background necessary to understand the application of LSPR and SERS to biological problems is presented and illustrative examples of resonant Rayleigh scattering, refractive index sensing, and SERS-based detection and labelling are discussed.

An electrochemical method is developed to quantitatively modify and spectroscopically monitor the size and shape of Ag nanotriangles fabricated by nanosphere lithography (NSL) on an indium tin oxide (ITO) electrode surface. AFM and SEM results demonstrate that the preferential order of electrochemical oxidation for a nanotriangle is, surprisingly, bottom edges first, then triangular tips, then out-of-plane height.

Nanosphere lithography (NSL) is an inexpensive, high throughput, materials general nanofabrication technique capable of producing a large variety of nanoscale structures including well-ordered 2 dimensional nanoparticle arrays. In this review, we will summarize the most recent advances in the fabrication of size-tunable nanoparticles using NSL. Four examples of new NSL-derived materials will be described: (1) The development of a method to release NSL nanoparticles from the substrate for applications in solution environments, (2) the fabrication of triangular nanoholes with reactive ion etching, (3) the electrochemical fine tuning of the structure of a silver nanoparticle and the wavelength of its localized surface plasmon resonance (LSPR), and (4) the growth of ultra thin protective dielectric layers on NSL-fabricated Ag nanotriangles using atomic layer deposition (ALD).