Ring-in-a-Triangle Nanoframes: Integrating with Intra- and Interhotspots for Highly Amplified Near-Field Focusing.The development of a stepwise synthetic strategy for Au ring-in-a-triangle nanoframes with a high degree of structural solidity is essential to the advancement of highly amplified near-field focusing. 
Au ring-in-a-triangle nanoframes
This strategy leads to the formation of an inscribed nanoring in a triangular metal frame with stability to withstand elevated temperatures and an oxidizing environment, which is critical for successful single-particle surface-enhanced Raman scattering (SERS). 
single-particle surface-enhanced Raman scattering (SERS)