TY - JOUR
T1 - Experimental approach to the fundamental limit of the extinction coefficients of ultra-smooth and highly spherical gold nanoparticles
AU - Kim, Dong Kwan
AU - Hwang, Yoon Jo
AU - Yoon, Cheolho
AU - Yoon, Hye On
AU - Chang, Ki Soo
AU - Lee, Gaehang
AU - Lee, Seungwoo
AU - Yi, Gi Ra
N1 - Publisher Copyright:
This journal is © the Owner Societies 2015.
PY - 2015/8/28
Y1 - 2015/8/28
N2 - The theoretical extinction coefficients of gold nanoparticles (AuNPs) have been mainly verified by the analytical solving of the Maxwell equation for an ideal sphere, which was firstly founded by Mie (generally referred to as Mie theory). However, in principle, it has not been directly feasible with experimental verification especially for relatively large AuNPs (i.e., >40 nm), as conventionally proposed synthetic methods have inevitably resulted in a polygonal shaped, non-ideal Au nanosphere. Here, mono-crystalline, ultra-smooth, and highly spherical AuNPs of 40-100 nm were prepared by the procedure reported in our recent work (ACS Nano, 2013, 7, 11064). The extinction coefficients of the ideally spherical AuNPs of 40-100 nm were empirically extracted using the Beer-Lambert law, and were then compared with the theoretical limits obtained by the analytical and numerical methods. The obtained extinction coefficients of the ideally spherical AuNPs herein agree much more closely with the theoretical limits, compared with those of the faceted or polygonal shaped AuNPs. In addition, in order to further elucidate the importance of being spherical, we systematically compared our ideally spherical AuNPs with the polygonal counterparts; effectively addressing the role of the surface morphology on the spectral responses in both theoretical and experimental manners.
AB - The theoretical extinction coefficients of gold nanoparticles (AuNPs) have been mainly verified by the analytical solving of the Maxwell equation for an ideal sphere, which was firstly founded by Mie (generally referred to as Mie theory). However, in principle, it has not been directly feasible with experimental verification especially for relatively large AuNPs (i.e., >40 nm), as conventionally proposed synthetic methods have inevitably resulted in a polygonal shaped, non-ideal Au nanosphere. Here, mono-crystalline, ultra-smooth, and highly spherical AuNPs of 40-100 nm were prepared by the procedure reported in our recent work (ACS Nano, 2013, 7, 11064). The extinction coefficients of the ideally spherical AuNPs of 40-100 nm were empirically extracted using the Beer-Lambert law, and were then compared with the theoretical limits obtained by the analytical and numerical methods. The obtained extinction coefficients of the ideally spherical AuNPs herein agree much more closely with the theoretical limits, compared with those of the faceted or polygonal shaped AuNPs. In addition, in order to further elucidate the importance of being spherical, we systematically compared our ideally spherical AuNPs with the polygonal counterparts; effectively addressing the role of the surface morphology on the spectral responses in both theoretical and experimental manners.
UR - http://www.scopus.com/inward/record.url?scp=84938674708&partnerID=8YFLogxK
U2 - 10.1039/C5CP02968F
DO - 10.1039/C5CP02968F
M3 - Article
AN - SCOPUS:84938674708
SN - 1463-9076
VL - 17
SP - 20786
EP - 20794
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 32
ER -