Localized surface plasmon resonance enhancement

L. Qiao, D. Wang, L. Zuo, Y. Ye, J. Qian, H. Chen, S. He, Localized surface plasmon resonance enhanced organic solar cell with gold nanospheres, Appl. Energy 88 (2011) 848-... 

Long period gratings modified by the deposition of a self-assembled colloid monolayer of gold have been shown to enhance SRI sensitivity, which was attributed to the localized surface plasmon resonance (LSPR) of gold nanoparticles61. The system was used after functionalization of the gold nanoparticles with dini-trophenyl (DNP) antigen, for the detection of anti-(DNP) with a limit of detection as low as 9.5 x 10 10 M. 

The optimal enhancement effect is observed when the localized surface plasmon resonance is tuned to the emission wavelength of a locally situated fluorophore [86]. This is consistent with the model suggesting a greatly increased efficiency for energy transfer from fluorophores to surface plasmons [78]. Since resonance energy transfer is involved, the important factors affecting the intensity of fluorescence emission must also be the orientation of the dye dipole moments relative to the... 

Kim K, Yoon SJ, Kim D (2006) Nanowire-based enhancement of localized surface plasmon resonance for highly sensitive detection a theoretical smdy. Opt Express 14 12419-12431... 

The metallic nanocrystals are remarkable due to their localized surface plasmon resonance (SPR) phenomenon, that is, the excitation of surface plasma by light. It ensures these nanocrystals to be color based sensors (Homola et al., 1999 Kelly et al., 2003). The metallic nanocrystals could also sensitize the Raman signals from their adsorbed organic molecules. This surface enhanced Raman scattering (SERS) effect potentially raises the detection sensitivity to single molecule level (Kneipp et al., 1997 Nie and Emery, 1997). 

Localized surface plasmon resonance (LSPR) at the metal surface has been exploited to enhance the signal obtained from optical biochips and thereby lower the limits of detection. There are two main enhancement factors (i) an increase in the excitation of the fluorophore by localizing the optical field on the nanoparticles near the fluorophore and (ii) an increase in quantum efficiency of the fluorophore. The plasmon resonance wavelength should coincide with the fluorophore absorption band to obtain the maximum emission efficiency. Several parameters concerning the signal detection enhancement are as follows (84)... 

Metal nanoparticles have attracted considerable interest due to their properties and applications related to size effects, which can be appropriately studied in the framework of nanophotonics [1]. Metal nanoparticles such as silver, gold and copper can scatter light elastically with remarkable efficiency because of a collective resonance of the conduction electrons in the metal (i.e., the Dipole Plasmon Resonance or Localized Surface Plasmon Resonance). Plasmonics is quickly becoming a dominant science-based technology for the twenty-first century, with enormous potential in the fields of optical computing, novel optical devices, and more recently, biological and medical research [2]. In particular, silver nanoparticles have attracted particular interest due to their applications in fluorescence enhancement [3-5]. 

There are two types of SERS mechanisms, which are responsible for the observation of the SERS enhancement [8] one type is the long-range EM effect and the other is the short-range CHEM effect. The EM effect is believed to be the result of localized surface plasmon resonance electric fields (hot spot) set up onto the roughened metallic surfaces [9, 10, 31]. The probe molecules residing within these hot spots will be strongly excited and subsequently emit amplified Raman... 

In recent years, it has become accepted within the SERS community that hot spots primarily arise from intense and highly localized electromagnetic fields caused by local surface plasmon resonances (LSPR). However, questions over the precise magnitude of the enhancement present at such locations have led some to suggest that there must be a chemical aspect to hot spots. In this section, the key results from recent work focusing on the fundamentals of hot spots with regard to these two components are summarized. 

Strong enhancement of light absorption over the spectral range of the copper localized surface plasmon resonance has been observed at two-layer planar systems of copper and silver nanopaiticles made with the use of successive vacuum evaporation. The result obtained is treated with taking into account strong near-fieid coupling at a close-packed array of silver and copper nanoparticles. 

Overall, SERS is essentially an effect of plasmon-enhanced Raman scattering, and any nanostructures that possess the ability to excite localized surface plasmon resonance in the UV-visible and near-IR regime can also support SERS. The optimization of key factors for localized surface plasmon resonance and Raman scattering will allow an optimization of... 

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