Morphological Design of Nanoparticle Assemblies: Application to Environmental Sensing

Silver nanoparticle deposition from suspension is proposed as a route for the morphological design of controllably disordered self-affine substrates for surfaceenhanced Raman sensing of water pollutants. Ionic strength is used as a variable parameter to control the deposition process and, ultimately, the morphology of deposited substrates. The critical dependence of the enhancement factor on the substrate morphology is leveraged to develop sensors with tunable sensitivity. Fractal analysis is used to quantify deposit morphologies and to correlate these to enhancement factors afforded by the substrates.