title: Probing the location of hot spots by surface-enhanced Raman spectroscopy: toward uniform substrates.
abstract: Wide applications of surface plasmon resonance rely on the in-depth understanding of the near-field distribution over a metallic nanostructure. However, precisely locating the strongest electric field in a metallic nanostructure still remains a great challenge in experiments because the field strength decays exponentially from the surface. Here, we demonstrate that the hot spot position for gold nanoparticles over a metal film can be precisely located using surface-enhanced Raman spectroscopy (SERS) by rationally choosing the probe molecules and excitation wavelengths. The finite difference time domain simulation verifies the experimental results and further reveals that the enhancement for the above system is sensitive to the distance between nanoparticles and the metal film but insensitive to the distance of nanoparticles. On the basis of this finding, we propose and demonstrate an approach of using a nanoparticles-on-metal film substrate as a uniform SERS substrate. This work provides a convenient way to probe the location of strong near-field enhancement with SERS and will have important implications in both surface analysis and surface plasmonics.
authors: State Key Laboratory of Physical Chemistry of Solid Surfaces, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Collaborative Innovation Center of Chemistry for Energy Materials, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, China.
authors: Xiang
authors: X
authors: Wang
authors: Maohua
authors: M
authors: Li
authors: Lingyan
authors: L
authors: Meng
authors: Kaiqiang
authors: K
authors: Lin
authors: Jiamin
authors: J
authors: Feng
authors: Tengxiang
authors: T
authors: Huang
authors: Zhilin
authors: Z
authors: Yang
authors: Bin
authors: B
authors: Ren