Langmuir-Blodgett silver nanowire monolayers for molecular sensing using surface-enhanced Raman spectroscopy

Langmuir-Blodgett technique was used to assemble monolayers (with areas over 20 cm(2)) of aligned silver nanowires that are similar to50 nm in diameter and 2-3 mum in length. These nanowires possess pentagonal cross-sections and pyramidal tips. They are close-packed and are aligned parallel to each other. The resulting nanowire monolayers serve as excellent substrates for surf ace-enhanced Raman spectroscopy (SERS) with large electromagnetic field enhancement factors (2 x 105 for thiol and 2,4-dinitrotoluene, and 2 x 109 for Rhodamine 6G) and can readily be used in ultrasensitive, molecule-specific sensing utilizing vibrational signatures.