Identification and characterization of artists' red dyes and their mixtures by surface-enhanced Raman spectroscopy.

Silver film over nanospheres (AgFONs) were successfully employed as surface-enhanced Raman spectroscopy (SERS) substrates to characterize several artists' red dyes including: alizarin, purpurin, carminic acid, cochineal, and lac dye. Spectra were collected on sample volumes (1 x 10(-6) M or 15 ng/microL) similar to those that would be found in a museum setting and were found to be higher in resolution and consistency than those collected on silver island films (AgIFs). In fact, to the best of the authors' knowledge, this work presents the highest resolution spectrum of the artists' material cochineal to date.

Advances in contemporary nanosphere lithographic techniques.

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).

Ultrastable substrates for surface-enhanced Raman spectroscopy: Al2O3 overlayers fabricated by atomic layer deposition yield improved anthrax biomarker detection.

A new method to stabilize and functionalize surfaces for surface-enhanced Raman spectroscopy (SERS) is demonstrated. Atomic layer deposition (ALD) is used to deposit a sub-1-nm alumina layer on silver film-over-nanosphere (AgFON) substrates. The resulting overlayer maintains and stabilizes the SERS activity of the underlying silver while presenting the surface chemistry of the alumina overlayer, a commonly used polar adsorbent in chromatographic separations.

Localized surface plasmon resonance nanosensor: a high-resolution distance-dependence study using atomic layer deposition.

Atomic layer deposition (ALD) is used to deposit 1-600 monolayers of Al(2)O(3) on Ag nanotriangles fabricated by nanosphere lithography (NSL). Each monolayer of Al(2)O(3) has a thickness of 1.1 A.

Surface enhanced Raman spectroscopy: new materials, concepts, characterization tools, and applications.

Surface-enhanced Raman spectroscopy (SERS) is currently experiencing a renaissance in its development driven by the remarkable discovery of single molecule SERS (SMSERS) and the explosion of interest in nanophotonics and plasmonics. Because excitation of the localized surface plasmon resonance (LSPR) of a nanostructured surface or nanoparticle lies at the heart of SERS, it is important to control all of the factors influencing the LSPR in order to maximize signal strength and ensure reproducibility. These factors include material, size, shape, interparticle spacing, and dielectric environment.