Effect of Linear Chain Lengths of 1‐Alkanethiols on Plasmon Damping of Single Gold Bipyramids with Sharp Tips

Abstract

Influence of linear chain length of 1-alkanethiols on FWHM shifts in single gold bipyramids with sharp tips. Figure S1 (a) TEM image of AuBPs measured in this study. (B) UV–Vis absorption spectrum of AuBPs dispersed in water. Figure S2. Size distribution. (a) Histogram to show the length distribution of AuBPs. (b) Histogram to show the distribution of width of AuBPs. The average length and width of AuBPs were 24.7 (±2.72) nm and 76.1 (±3.78) nm, respectively. Figure S3. Working principle of dark-field (DF) microscopy and spectroscopy. Figure S4. A photograph to show the experimental setup for single particle microscopy and spectroscopy. Figure S5. (a) Normalized single particle scattering spectra of AuBPs in ethanol. (b) Normalized single particle scattering spectra of AuBPs after introducing 1-decanethiol in ethanol (1 μM). Figure S6. The LSPR wavelength shift as a function of carbon chain lengths of 1-alkanethiols (C4, C6, C8, C10, C16) for AuBPs. Figure S7. Change in the scattering intensity of single AuBPs as a function of the chain length from C4 to C16. The scattering intensity was exponentially decreased with increasing the chain length. Figure S8. DLS measurements of thiolated AuBPs. (a–e) The change of the particle size of thiolated AuBPs in solution as a function of the chain length from C4 to C16, measured by a dynamic light scattering (DLS) measurement. The DLS measurement was performed right after sonicating the solution containing the thiolated AuBPs. (f) Comparison of the particle size as a function of the thiol chain length. The effective binding of thiol on the particle surfaces as well as the size increase depending on the chain length is supported by the DLS measurements. Figure S9. DLS measurement to show change in the particle size of AuBPs coated with 1-octanethiol (C8) in solution as a function of time (time interval of 150 s). We can observe a tendency of the aggregate formation over time in thiolated AuBPs in solution. However, in this study, we measured the FWHM shift of single AuBPs deposited on a glass slide. Throughout all of the measurements in this study, the concentration of AuBPs on the glass slide was controlled to be about 1 μm−2 to facilitate single particle characterization. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.