Disclosed herein is a method for making a nanoparticle film comprising
dispersing nanoparticles in a first liquid; adding a second liquid to the
first liquid to form a nanoparticle film on top of a solution comprising
the first liquid, the second liquid and the nanoparticles, wherein the
second liquid has a dielectric constant that is different from a
dielectric constant of the first liquid; and contacting a substrate with
the solution to deposit the nanoparticle film onto the contacted portion
of the substrate. Disclosed herein too is a method for detecting an
analyte comprising dispersing nanoparticles in a first liquid; adding a
second liquid to the first liquid to form a nanoparticle film on top of a
solution comprising the first liquid, the second liquid and the
nanoparticles, wherein the second liquid has a dielectric constant that
is different from a dielectric constant of the first liquid; contacting a
substrate with the solution to deposit the nanoparticle film onto the
substrate; disposing upon the nanoparticle film an analyte; and
performing surface enhanced Raman spectroscopy to determine the identity
of the analyte.