Rhodium concave nanocubes and nanoplates as deep‐UV resonant SERS platform

Abstract We report on the detection of molecules at the trace level using deep‐UV surface‐enhanced Raman spectroscopy (SERS) on shape‐anisotropic rhodium (Rh) nanoparticles. Rh nanoparticles of three distinct morphologies, triangular nanoplates, rectangular nanoplates, and concave nanocubes, that exhibit strong plasmon resonances in the UV range were exploited for deep‐UV SERS. With an enhancement factor greater than 10 5 , Rh concave nanocubes demonstrate the highest SERS activity, which is well corroborated by electric field distribution maps calculated using finite‐difference time‐domain (FDTD) simulations. The deep‐UV SERS substrate based on Rh concave nanocubes enables the detection of trace levels of explosive molecules such as p‐nitrobenzoic acid and 2,4‐dinitrotoluene with detection limits of 10 −10 M and 10 −7 M, respectively, and ammonium nitrate with a detection limit of 10 −12 M. Deep‐UV SERS detection of explosive molecules on a low‐cost and simple‐to‐fabricate Rh nanoparticles substrate holds tremendous potential for the SERS‐based identification of hazardous materials.