Role of Linear Carbon Chains in the Aggregation of Copper, Silver, and Gold Nanoparticles

Abstract

Most of the applications involving metal nanoparticles require a high resistance to aggregation and oxidation phenomena to preserve and modulate the peculiar reactivity, electronic, optical, and magnetic properties of nanoparticles. Linear carbon chains (LCCs) containing sp hybridization either as alternating triple and single bonds (polyynes) or with consecutive double bonds (cumulenes) are good candidates to create a shell that prevents such unwanted degradation phenomena. In addition, the development of reliable experimental protocols for their synthesis over a range of sizes and high monodispersity is an important challenging issue in most of the biological applications. In this Article, we investigate the interaction between LCCs and different metal nanoparticles (Cu, Au, Ag) to provide an insight into the factors influencing chemical (reactivity) and physical (optical) properties of the metal/LCCs core/shell systems produced at different experimental conditions. For this purpose, a range of different complementary experimental techniques such as Raman and UV-vis spectroscopy, transmission electron microscopy, and mass spectrometry are applied, and details on the different LCCs produced as well as insights into the metal-carbon bonds formed are unveiled.

Surface-enhanced Raman scattering investigations of C2nH2 (n=4–6) in as-prepared and dried Ag colloid

“…After the colloid runs dry, the 2930 cm −1 feature may originate from the precursor residue during preparing Ag colloid. Besides, the intensity of G band at 1558 cm −1 increases, due to the more effective cross-linking processes in dried Ag colloid [20]. The experimental results are the same when the excitation wavelength turns to 633 nm.…”

Stability improvement of C8H2 and C10H2 embedded in poly(vinyl alcohol) films with adsorption on gold nanoparticles

“…The characteristic bands of Au/polyynes/PVA film lie in the 1300-1700 cm -1 region are thought from sp 2 hybridized carbon structures [8]. Generally, the unstable polyynes reorganize towards more stable sp 2 phases by chain-chain cross-linking reactions [13].…”

“…Although mainly two Raman modes of C 2n H 2 were reported by many researchers [10][11][12][13], the positions considerably differ from each other. Hanamura et al [10] found that the SERS bands of C 8 H 2 adsorbed on Ag island film show a redshift than the Ag colloids.…”

“…Compagnini et al [12] got polyynes adsorbed on silver surfaces and the results showed two strong bands, but only one band on gold surfaces (the band at low frequencies disappears). D'Urso et al [13] studied the interaction between polyynes and different metal nanoparticles (Cu, Au, Ag) and found polyynes-Au interactions are not as efficient as for Ag. These results indicate the SERS of polyynes strongly depend on the nature of SERS enhancers.…”

“…Because Raman band of C 2 H 2 adsorbed on Ag surface by weak π interaction shows redshift compared to Raman band of gaseous C 2 H 2 . D Urso et al[13] investigated polyyne solutions mixed with Au or Ag colloids by Raman spectrum and mass spectrometry (MS). However, the intensity of Raman signals of polyynes is lower in Au colloids compared to Ag colloids.…”