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 SiNW-FET 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.

Design of multi-functional 2D open-shell organic networks with mechanically controllable properties

“…4,5 The radical π-conjugation in TAMs is responsible for many of their key characteristics such as fluorescence, 6 enhanced electrical conductivities, 7 redox-activity 8,9 and magnetoresistance phenomena. 10 As a consequence, TAMs have been utilized for the preparation of organic magnets, 12–14 non-volatile memory devices, 8 molecular wires, 10,15 switchable surfaces, 9 dynamic-nuclear polarization components, 16 organic light emitting diodes 17 and nano-porous magnetic sensors, 18 among others. 19 …”

“…However, chemical design is, by far, the most utilized approach to finely tune this structural parameter to a certain value in order to determine the associated electrical, 24,28 magnetic, 29 optical 30 and electro-chemical properties. 25 The challenging task of externally tuning aryl ring twist angles in single-molecule devices comes from the extreme difficulties associated with: (i) controlling the orientation of the molecular units within the device 15 and, (ii) the need to direct the external stimulus uniquely to twist aryl rings without causing other physico-chemical phenomena which may also interfere with the output characteristics of the system. 10 …”

Amino‐Induced 2D Cu‐Based Metal–Organic Framework as an Efficient Heterogeneous Catalyst for Aerobic Oxidation of Olefins

“…Metal–organic polyhedra (MOPs) as crystalline coordination materials that are constituted by metal ions and organic ligands . Owing to their unique features, such as permanent porosity and unsaturated metal centers, MOPs have shown great potential for applications in drug delivery, gas adsorption and storage, chemical sensors, and catalysis . As a common ligand isophthalic acid and its corresponding derivatized ligands have been widely used to prepare MOP materials .…”

Hybrid Silicon Nanowire Devices and Their Functional Diversity

“…These functional groups can protonate or deprotonate depending on the pH value of the solution, resulting in a linear conductance response of the device in a pH range between 2 and 9. [67,68] Definitely, silicon has been attractive also as a photodetecting material due to the convenient integrability with CMOS technology. [45] Inspired by these works, myriads of publications have exploited the broad range of possibilities in SiNW sensorics (Figure 1), from detection of biomolecules for diagnostic purposes [36,37,[52][53][54][55] to recording of cell activity, [46,[56][57][58][59][60][61] intracellular signal control, [49,62,63] tissue monitoring, [4,25] food safety, [64] and gas [65,66] and explosive sensing.…”