SERS intensity optimization by controlling the size and shape of faceted gold nanoparticles

Abstract

In this work, we experimentally investigated the surface-enhanced Raman spectroscopy (SERS) activity of faceted gold nanoparticles, which have been theoretically predicted to yield giant enhancements. Glycine was used to determine the SERS activity as a function of pH and ionic strength and to estimate the corresponding enhancement factor (EF). By optimizing the synthesis conditions of the flat prismatic nanoparticles, it was possible to control their size and shape. We demonstrate that the maximum SERS intensity increases with the edge length of the triangle, reaching a maximum EF of ∼10 13 for 1.9 µm triangles (the largest tested). The corresponding glycine detection limit was as low as 10 −12 M, close to the single-molecule threshold.

SERS enhancement of gold nanospheres of defined size

“…In the case of colloidal substrates, particle shape and size were shown to influence the enhancement of the Raman signals through their optimum excitation wavelength that is implied by the position of the plasmon extinction band of the nanoparticles. [10,11] Studies were conducted with different probe molecules, among them rhodamine B, [12] crystal violet (CV), [13] glycine, [14] and trans-1,2-bis (4-pyridyl)ethylene. [15] The dependence of the electromagnetic contribution to SERS enhancement on nanoparticle size has been investigated in many theoretical studies.…”

Nanoparticle SERS Substrates

“…For nanoparticles with various shapes, the size effect also plays a great role for the overall SERS enhancement. For instance, Sant'Ana et al reported the size-dependent SERS enhancement of colloidal silver nanoplates in suspension without aggregation [141], and Sabur reported the SERS intensity optimization by controlling the size and shape of faceted gold nanoparticles [142]. However, the shape effect will dominate more for these kinds of nanoparticles [143,144] due to their shape-dependent and tunable LSPR residing in the nanoparticles (see also Chapter 1).…”

Recent advances in linear and non‐linear Raman spectroscopy. Part III

“…Sabur et al [3] have experimentally investigated the SERS activity of faceted gold nanoparticles, which have been predicted to yield giant enhancements. Enhancement factors of up to 10 13 for 1.09 µm nanotriangles were reported.…”

“…Such studies are compiled here for the following molecules: 1H-and 3H-imidazo [4,5-b]pyridine and their methyl derivatives, [113] copper(II) chloride and bromide compounds of KCuBr 3 , [114] 5,6-diméthyluracile, [115] [C(NH 2 ) 3 ] 2 M II (H 2 O) 4 (SO 4 ) 2 , M II = Mn, Cd and VO, [116] potassium trimethylsilanolate, [117] 2-aminopyridinium-4-hydroxybenzenosulfonate, [118] the H 4 I 2 O 10 2− ion in CuH 4 I 2 O 10 · 6H 2 O, [119] 2-amino-4,6-dihydroxypyrimidine, [120] 3 (or 4 or 6)-methyl-5-nitro-2-pyridinethiones, [121] 2-methyl-4-nitroaniline (MNA) crystal, [122] 2-amino-5-chloropyridinium hydrogen selenate, [123] the food dye amaranth, [124] transstilbene in the excited singlet state, [125] chloramphenicol, [126] oroxylin, [127] 4-fluoro-N-(2-hydroxy-4-nitrophenyl)benzamide, [128] phenanthridine, [129] 3,5 dichloro hydroxy benzaldehyde and 2,4 dichloro benzaldehyde. [130] Solid State (Minerals, Crystals, Linear Chains, Glasses, Ceramics and Disordered Materials) Minerals A great number of minerals have been studied during 2008 by the Frost group [131 -146] using both Raman and infrared spectroscopies: smithsonite, [131] the uranyl carbonate mineral voglite, [132] hydrotalcite with CO 3 2− and (MoO 4 ) 2− anions in the interlayer, [133] the uranyl phosphate minerals phosphuranylite and yingjiangite, [134] the uranyl carbonate mineral zellerite, [135] the molybdate-containing uranyl mineral calcurmolite, [136] the oxalate mineral wheatleyite Na 2 Cu 2+ (C 2 O 4 ) 2 ·2H 2 O, [137] the nickel silicate mineral pecoraite, [138] synthetic nesquehonite, [139] the uranyl mineral, compreignacite, K 2 [(UO 2 ) 3 O 2 (OH) 3 ] 2 ·7H 2 O, [140] the hydroxy nickel carbonate minerals nullaginite and zaratite, [141] schmiederite Pb 2 Cu 2 [(OH) 4 |S...…”