Sustainable
Surface-Enhanced Raman Substrate with
Hexagonal Boron Nitride Dielectric Spacer for Preventing Electric
Field Cancellation at Au–Au Nanogap
posted on 2021-08-26, 13:06authored byJong-Guk Ahn, Gyeonghun Yeo, Yeji Han, Younghee Park, Jong Wook Hong, Hyunseob Lim
Nanogaps
between Au nanoparticles and Au substrates are the simplest
systems that generate extremely high electric fields at hotspots for
surface-enhanced Raman spectroscopy (SERS). However, the electric
field cancellation at the hotspots in the systems can cause the reduction
of Raman signal when two metallic materials are physically contacted
due to the low concentration of analytes. Here, we propose an atomically
thin hexagonal boron nitride (h-BN) shielding layer
for Au substrates, which can be used as an insulating spacer to prevent
electrical shorts at nanogaps. Experimental investigation of the SERS
effect combined with theoretical studies by finite-difference time-domain
simulations demonstrate that the Au NP/h-BN/Au substrate
structure has excellent performance in electrical short prevention,
thus facilitating ultrasensitive Raman detection. The outstanding
chemical and thermal stability of h-BN allow the
efficient recycling of the SERS substrate by protecting the Au surface
during the removal of Au NPs and molecular analytes by chemical and
thermal processes.