Optimal geometric parameters of ordered arrays of nanoprisms for enhanced sensitivity in localized plasmon based sensors

•We model the nanoprisms array-based plasmonic biosensors.•We carry out a systematic analysis on the sensitivity varying geometric parameters.•We determine the resonance wavelength as a function of geometric parameters.•We determine the best parameters for building local and bulk sensors.•We consider the role of the metal, modeling Au, Ag and AuAg alloy.

Plasmonic sensors based on ordered arrays of nanoprisms are optimized in terms of their geometric parameters like size, height, aspect ratio for Au, Ag or Au0.5–Ag0.5 alloy to be used in the visible or near IR spectral range. The two figures of merit used for the optimization are the bulk and the surface sensitivity: the first is important for optimizing the sensing to large volume analytes whereas the latter is more important when dealing with small bio-molecules immobilized in close proximity to the nanoparticle surface. A comparison is made between experimentally obtained nanoprisms arrays and simulated ones by using Finite Elements Methods (FEM) techniques.