Characterization of Tetrahexahedral Gold Nanocrystals: A Combined Study by Surface-Enhanced Raman Spectroscopy and Computational Simulations

Tetrahexahedral (THH) and elongated tetrahexahedral (ETHH) gold nanocrystals (NCs) were fabricated and were studied for their unique surface plasmon (SP) excitation. UV-vis absorption spectra and surface-enhanced Raman scattering (SEAS) were introduced to experimentally investigate the far-field optical properties and near-field enhancement ability of nanoparticles. Calculation of electric field distribution on the basis of three-dimensional finite-difference time domain (3D-FDTD) method revealed that the E-field enhancement is largely confined to tips with strong dependences on geometry of tip and polarization of incident light. Enhancement factors were estimated, and several influence factors such as coupling effect were mentioned with discussion for the potential advantages of polyhedron-like structure in plasmon-related application.