LP-CVD Fabrication of Silver Films on Liquid Surfaces for Surface-Enhanced Raman Scattering Detection.

Silver nanostructured films are fabricated on the surface of 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid via a modified liquid-phase chemical vapor deposition approach, yielding highly uniform and reproducible surface-enhanced Raman scattering (SERS) substrates with excellent sensing sensitivity. Benefiting from the superior atomic diffusivity and weak interfacial confinement of the liquid substrate, the as-deposited Ag nanostructures generate robust plasmonic coupling and uniformly distributed hot spots, which serve as two critical factors for achieving prominent Raman signal enhancement. Rhodamine 6G is employed as a probe molecule to systematically investigate the SERS performance of the fabricated substrates by varying the mass of silver powder and the deposition distance. Combined with finite-difference time-domain (FDTD) simulations, the results confirm that optimized deposition parameters significantly improve the Raman signal intensity, substrate uniformity, and detection reproducibility. This work provides a feasible and controllable strategy for the construction of liquid-template-assisted Ag nanostructures and establishes a reliable platform for the design and preparation of high-performance SERS sensing devices.