TY - JOUR
T1 - Surface enhanced Raman scattering with gold nanoparticles
T2 - Effect of particle shape
AU - Tian, Furong
AU - Bonnier, Franck
AU - Casey, Alan
AU - Shanahan, Anne E.
AU - Byrne, Hugh J.
N1 - Publisher Copyright:
© the Partner Organisations 2014.
PY - 2014/11/21
Y1 - 2014/11/21
N2 - The dependence of the Surface Enhanced Raman Scattering (SERS) by gold nanoparticles on their shape is examined using the organic dye, rhodamine 6G (R6G) as probe molecule. SERS has been explored extensively for applications in sensing and imaging, but the design and optimisation of efficient substrates is still challenging. In order to understand and optimise the SERS process in nanoparticles, gold nanospheres and their aggregates, nanotriangles, and nanostars of similar dimensions were synthesised and characterised according to their average size, zeta potential and UV/visible absorption. SERS from R6G was negligible for unaggregated nanospheres at 532 nm, close to the maximum of the surface plasmon resonance (SPR) at 560 nm. Upon aggregation of the nanospheres, the SPR shifts to ∼660 nm, attributable to local surface plasmon "hotspots" between the spheres, and the SERS signal of R6G is significantly increased, at 785 nm. In monodisperse gold nanotriangles, the SPR is located at ∼800 nm, and significant SERS of R6G is observed using 785 nm as source, as is the case for gold nanostars, which exhibit a double SPR with maxima at ∼600 nm and ∼785 nm, attributable to the core sphere and vertices of the structures, respectively. In suspensions of equal nanoparticle and dye concentration, the SERS effect increases as nanospheres < nanosphere aggregates < nanotriangles < nanostars, clearly indicating that control over the number of local field hotspots can optimise the SERS efficiency. Notably, it is demonstrated that the SERS intensity per nanoparticle scales with the magnitude of the SPR absorbance at the excitation wavelength (785 nm), providing a clear guide to optimisation of the process experimentally.
AB - The dependence of the Surface Enhanced Raman Scattering (SERS) by gold nanoparticles on their shape is examined using the organic dye, rhodamine 6G (R6G) as probe molecule. SERS has been explored extensively for applications in sensing and imaging, but the design and optimisation of efficient substrates is still challenging. In order to understand and optimise the SERS process in nanoparticles, gold nanospheres and their aggregates, nanotriangles, and nanostars of similar dimensions were synthesised and characterised according to their average size, zeta potential and UV/visible absorption. SERS from R6G was negligible for unaggregated nanospheres at 532 nm, close to the maximum of the surface plasmon resonance (SPR) at 560 nm. Upon aggregation of the nanospheres, the SPR shifts to ∼660 nm, attributable to local surface plasmon "hotspots" between the spheres, and the SERS signal of R6G is significantly increased, at 785 nm. In monodisperse gold nanotriangles, the SPR is located at ∼800 nm, and significant SERS of R6G is observed using 785 nm as source, as is the case for gold nanostars, which exhibit a double SPR with maxima at ∼600 nm and ∼785 nm, attributable to the core sphere and vertices of the structures, respectively. In suspensions of equal nanoparticle and dye concentration, the SERS effect increases as nanospheres < nanosphere aggregates < nanotriangles < nanostars, clearly indicating that control over the number of local field hotspots can optimise the SERS efficiency. Notably, it is demonstrated that the SERS intensity per nanoparticle scales with the magnitude of the SPR absorbance at the excitation wavelength (785 nm), providing a clear guide to optimisation of the process experimentally.
UR - http://www.scopus.com/inward/record.url?scp=84908102514&partnerID=8YFLogxK
U2 - 10.1039/c4ay02112f
DO - 10.1039/c4ay02112f
M3 - Article
AN - SCOPUS:84908102514
SN - 1759-9660
VL - 6
SP - 9116
EP - 9123
JO - Analytical Methods
JF - Analytical Methods
IS - 22
ER -