Metal-organic polyhedra-coated Si nanowires for the sensitive detection of trace explosives

Abstract

Surface-modified silicon nanowire-based field-effect transistors
(SiNW-FETs) have proven to be a promising platform for molecular
recognition in miniature sensors. In this work, we present a novel nanoFET
device for the sensitive and selective detection of explosives based on affinity
layers of metal−organic polyhedra (MOPs). The judicious selection of the
geometric and electronic characteristics of the assembly units (organic ligands
and unsaturated metal site) embedded within the MOP cage allowed for the
formation of multiple charge-transfer (CT) interactions to facilitate the selective
explosive inclusion. Meanwhile, the host-stabilized CT complex inside the cage
acted as an effective molecular gating element to strongly modulate the electrical conductance of the silicon nanowires. By grafting the MOP cages onto a SiNWFET device, the resulting sensor showed a good electrical sensing capability to various explosives, especially 2,4,6-trinitrotoluene (TNT), with a detection limit below the nanomolar level. Importantly, coupling MOPswhich have tunable structures and propertiesto SiNW-based devices may open up new avenues for a wide range of sensing applications, addressing
various target analytes.