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Arina I. Psareva, Tatiana I. Shabatina, Vladimir E. Bochenkov
Improving refractive index sensitivity of triangular
gold nanoprisms by reducing the substrate effect
Abstract
Abstract. Sensitivity of surface
plasmon resonance to the changes of the refractive index near metal
nanostructures enables their application as a universal platform for
biosensing. Improving the sensitivity of such systems, that would allow the
detection of tiny changes in refractive index due to adsorption of a small
amount of analyte on the surface of plasmonic nanoparticles, is of great
practical importance. One of the approaches to enhanced sensitivity of
plasmonic nanostructures is to reduce the so-called “substrate effect”: since a
significant part of enhanced electric field is directed into the substrate, it
becomes inaccessible to the analyte molecules and hence is not involved in
sensing. Here, by using finite-difference time-domain simulations, we study the
bulk refractive index sensitivity of elevated gold nanoprisms as a function of
the thickness of an additional dielectric layer. We show that the effect
reaches the value of 42 ± 6% at the spacer layer thickness of 15 nm. Further
increase of the dielectric layer thickness does not lead to any sensitivity
change.
Copyright (C) Chemistry Dept., Moscow State University, 2002
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