Surface-enhanced Raman scattering (SERS) technique has been utilized in fields ranging from space exploration to biomedical sensing.  Exploring new materials, shapes, and assembly processes with improved reliability and sensitivity has significantly expanded SERS applications.  In this work, we report a novel route in fabricating highly active SERS substrates with tailored enhancement mechanisms.  Langmuir-Blodgett thin films of silver nanowires were manufactured and then processed via galvanic replacement reaction.  This room temperature reaction provided an efficient approach to decrease spectral noises related to the capping agent, polyvinylpyrrolidone, of the nanowires.  The addition of gold nanostructures to the Ag NW system is believe to be responsible for decreasing the noises and revealed Raman signals from nonfluorescent molecules associated with a charge-transfer mechanism.  An ultrasensitive SERS substrate was demonstrated with its capability of detecting 4-aminothiophenol at a concentration of 8 nM.  Overall, our work provided an efficient approach in tailoring SERS substrates for more reliable detections of nonfluorescent molecules in a controlled manner.

Tunable surface-enhanced Raman scattering of chemically modified silver nanowire thin films

247th National Meeting (2014)

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