LSPR Nanostructures for SERS

The overall goal of this proposed program (through Phase III) is to develop a chemical warfare agent analyzer capable of detecting vapor phase agents at 10-7g/m3 in less than 1 minute. This will be accomplished by developing a method to produce novel localized surface plasmon resonance (LSPR) nanostructures, supported by theory, that produce a minimum surface-enhanced Raman scattering (SERS) enhancement of 1010, and incorporating them into an air collection sampling system coupled to a field-usable Raman spectrometer. Feasibility will be demonstrated during Phase I by developing and identifying LSPR structures that produce SERS with enhancement factors of 106 and greater using three chemicals, benzenethiol, dimethyl methylphosphonate, and methylphosphonic acid. 2-chloroethyl ethylsulfide will be measured in the vapor phase during an option task. The overall goal of the Phase II program will be to develop a prototype analyzer that can measure 10 chemical agent simulants at 10-7g/m3 concentration in less than 1 minute. This will be accomplished by optimizing the enhancement of the LSPR substrates (through theory and manufacturing), incorporating them into an air collection system coupled to a Raman spectrometer, and quantifying sensitivity. The Phase III program will focus on measuring real chemical agents and developing a field testable system.