Interfacial self-assembly of nanostructured silver octahedra for surface-enhanced Raman spectroscopy

A novel robust and effective approach is suggested to form thin film substrates for surface-enhanced Raman spectroscopy (SERS) using interfacial self-assembly in demixing water/toluene Pickering emulsions collecting silver octahedral mesocages onto a finally flat interfacial region. The freely floating self-assembled silver films obtained after toluene evaporation can be transferred onto various substrates including those with an ordered superficial relief causing a further alignment of silver octahedra. A special porous aggregative structure of the octahedra mesocages provokes a great number of hot spots allowing a large amplification of Raman scattering signal of model dye analytes and molecular thiol products of crude oil desulfurization. The suggested method seems to be an easy scaling route for SERS active material production.