کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1230588 1495240 2014 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Hyper-Rayleigh scattering from gold nanoparticles: Effect of size and shape
ترجمه فارسی عنوان
پراکندگی بیش از حد ریلی از نانوذرات طلا: اثر اندازه و شکل
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
چکیده انگلیسی


• Hyper-Rayleigh scattering from five different gold nanoparticles are compared.
• Star and flower shaped particles were observed to have highest hyperpolarizability.
• The hyper-Rayleigh scattering from the nanoparticles showed a dipolar response.

We report hyper-Rayleigh scattering (HRS) properties of gold nanoparticles (GNPs) of five different shapes, quasi-spherical (∼10 and ∼20 nm diameter), rod (aspect ratio ∼2), and branched shapes, tetrapod, flower and star with 800 nm, 150 fs laser excitation. Using ∼10 nm spherical GNPs as reference, the first hyperpolarizability (β) values were calculated for all other shapes. Star and flower shaped GNPs have the highest hyperpolarizability (∼130 and ∼52 times higher, respectively), while rod and tetrapod shaped GNPs only have modest enhancement (∼7 times), which is similar to ∼20 nm size quasi-spherical particles. These enhancements are attributed to reduced symmetry as well as the presence of sharp tips on GNP surface. When the β values are normalized with respect to the number of atoms per particle, the flower and star shaped GNPs still have the highest hyperpolarizability values. The polar plots of vertically polarized HRS signal as a function of the angle of polarization of the incoming incident light shows two lobes, indicating that excitation is predominantly dipolar in nature although the size of some GNPs are big enough to show a quadrupolar response. It is believed that the presence of sharp tips at the surface of these large sized GNPs is responsible for the observed dipolar response. This study shows that GNPs having sharp tips might be a better candidate when their nonlinear properties are used for sensing applications.

First hyperpolarizability (β) values of gold nanoparticles: Effect of size and shapeFigure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy - Volume 128, 15 July 2014, Pages 398–402
نویسندگان
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