Size Correlation of Optical and Spectroscopic Properties for Gold Nanoparticles

Abstract

While the optical and spectroscopic properties of gold nanoparticles are widely used for chemical, bioanalytical, and biomedical applications, the study of the size correlation with these properties for nanoparticles in solutions is rather limited. This paper describes the results of a systematic study of such a correlation for gold nanoparticles with diameters ranging from 10 to 100 nm in aqueous solutions. The high monodispersity of these nanoparticles permitted a meaningful correlation of the particle size with the surface plasmon (SP) resonance band properties and the surface-enhanced Raman scattering (SERS) spectroscopic properties. This correlation is compared to the results from the simulation based on Mie theory. The close agreement between the experimental and the theoretical results provides insight into the validity of determining the wavelength of the SP resonance band as a measure of the particle size. The size correlation with the SERS intensity from the adsorption of 4-mercaptobenzoic acid on the nanoparticles in aqueous solutions reveals the existence of a critical size of the nanoparticles in the solution beyond which the particle−particle interaction is operative and responsible for the SERS effect. These findings serve as the basis of size correlations for exploiting the optical and spectroscopic properties of gold nanoparticles of different sizes in aqueous solutions in analytical or bioanalytical applications.

The impacts of nanotechnology on catalysis by precious metal nanoparticles

“…In contrast, ligand-protected nanoparticles of extremely narrow size distribution (e.g., 5 % standard deviation) can now be readily obtained in solution phase. For example, uniform Au nanoparticles with size ranging from ∼ 1 nm to ∼ 100 nm [100][101][102][103] can now be routinely made; for example, Eah and coworkers reported uniform Au nanoparticles ranging from ∼ 3 to ∼ 8 nm ( Figure 23 ) [101,102] . The available uniform nanoparticles will allow one to carry out more precise measurements of size dependence in catalytic tests in future work.…”

Polymer-functionalized Gold Nanoparticles as Versatile Sensing Materials

“…10 nm exhibit an extinction band around 520 nm due to their inherent surface plasmon band when disassembled in a solution. [15][16][17] The maximum wavelength of the extinction spectra of AuNPs is correlated to the morphology of AuNPs by Mie theory. 18,19 The addition of ionic substances or other external stimuli causes the assembly of AuNPs because of the instability of disassembled AuNPs.…”

MOVPE Self-Assembly and Physical Properties of Free-Standing III-V Nanowires

“…5(a) reports the linear optical absorption coefficient spectrum measured at RT for one such Au colloidal solution (with NP size around 23.4 nm and volume density around 10 11 cm -3 ) with the strong plasmonic resonance of Au NPs peaked at around 518 nm. The resonance shifts its peak wavelength position and width with the actual size of the NPs (Njoki et al, 2007); however, it is difficult to determine both the average size and dispersion of the NPs from the optical absorption spectra of colloidal solutions, especially for NP diameters in the 10÷30 nm range. The size dispersion of colloidal Au NPs can be more precisely studied by FE-SEM observations upon deposition of the NPs on a solid support.…”