Narrow Results

A new simple approach is suggested to prepare surface enhanced Raman spectroscopy (SERS) substrates with high effectiveness for various laser excitation wavelengths and analytes with different light absorption features by impregnation of porous cellulose materials by a mixture of silver nanoplatelets with a wide range of sizes and anisotropy. The suggested route provides a much better spectral sensitivity and flexible applications since SERS as a phenomenon is essential on the nanometer scale only. The mixing provides always a proper fraction of silver nanoparticles deposited onto the substrate thus guaranteeing the enhancement of Raman signals under given excitation conditions for a wider set of given analytes. The substrates were successfully prepared for the first time from silver nanoplatelets aged for five years. This confirms high chemical and morphological stability of stabilized silver nanoparticles and the ability to use them as precursors for application - ready materials.

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.