Cross‐Linked Gold Nanoparticle Composite Membranes as Highly Sensitive Pressure Sensors

Abstract

In this article, highly sensitive differential pressure sensors based on freestanding membranes of cross-linked gold nanoparticles are demonstrated. The nanoparticle membranes are employed as both diaphragms and resistive transducers. The elasticity and the pronounced resistive strain sensitivity of these nanometer-thin composites enable the fabrication of sensors achieving high sensitivities exceeding 10 −3 mbar −1 while maintaining an overall small membrane area. Furthermore, by combining micro-bulge tests with atomic force microscopy and in situ resistance measurements the membranes' electromechanical responses are studied through precise observation of the concomitant changes of the membranes' topography. The study demonstrates the high potential of free-standing nanoparticle composites for the fabrication of highly sensitive force and pressure sensors and introduces a unique and powerful method for the electromechanical investigation of these materials.

Lithographic Patterning and Selective Functionalization of Metal Nanoparticle Composite Films

“…The disordered structure obtained is in good agreement with earlier studies employing the rapid layer-by-layer spincoating procedure. 12,34 With regard to their use as resistive sensors, the charge transport properties of the GNP film sections were investigated. Figure 1b shows the IV curves of eight film sections consisting of 9DT cross-linked 3.8 nm-sized GNPs.…”

“…In this work, we focus on alkanedithiol cross-linked gold nanoparticle (GNP) composites, which were reported as suitable transducers for strain − or chemiresistive sensors. ,, Thin films of cross-linked GNPs can be deposited following a rapid and facile layer-by-layer spin-coating-based procedure and show an enhanced mechanical stability, which enables the fabrication of, e.g., free-standing membranes for applications in hybrid nano- and microelectromechanical devices (NEMS/MEMS). ,,, Patterning of these GNP films was achieved by a lift-off process on oxidized silicon wafers. This process is expected to be transferable to a variety of otheralso flexiblesubstrates, such as polymers.…”

“…Composite films of organically stabilized or cross-linked metal nanoparticles attracted significant interest due to their applicability as resistive sensing materials for physical or chemical stimuli, i.e., as strain/pressure sensors − and as chemiresistors. − In the first case, strain or pressure directly affects the interparticle spacing, which governs tunneling currents between neighboring particles and hence the resistivity of the materials. Besides being used as strain-sensitive films on flexible substrates, − free-standing metal nanoparticle composites were lately introduced as suitable functional components for novel hybrid micro- and nanoelectromechanical (MEMS/NEMS) systems. − In the second case, the organic matrix separating the nanoparticles enables sorption of analyte molecules, which, in turn, leads to swelling and affects its permittivity. Swelling increases the interparticle spacings and consequently the resistivity of the composite, which can be measured as the sensing signal.…”

Flexible Plasmonic Biosensors for Healthcare Monitoring: Progress and Prospects

“…Flexible plasmonic biosensors, a group of emerging sensors introducing responsive noble metal nanoparticles (NPs) into flexible systems, have been utilized in monitoring human health, disease diagnosis, and environmental pollution analysis, etc . − The “plasmonic unit” enables sensors with some properties, such as (1) the charge-transport properties and resistive sensitivity to strain changes, , (2) the ability to enhance fluorescence and Raman signal driven by the localized surface plasmon resonance (LSPR), , (3) the inherent optical response to target analytes, , and (4) the high designability on the surface modification of noble metal nanoparticles. , Such flexible plasmonic biosensors possess superiorities with the conformal attachment to skin and multisensing capabilities. However, the progress of emerging flexible plasmonic biosensors has not been systematically reviewed elsewhere. − …”

Rational Design of All Resistive Multifunctional Sensors with Stimulus Discriminability

“…[20,22] Therefore, it is highly desired to develop sensitive multifunctional sensors having stimulus discriminability and yet benefiting from simple, cost-effective fabrication, and readout systems, for instance, a multifunctional sensor whose outputs are only given in electrical resistance signals. [30] However, such all resistive multifunctional sensors capable of stimulus discriminability have rarely been reported to date because conductive fillers, such as graphene, [31][32][33] carbon nanotubes, [34][35][36] and metal nanoparticles, [37][38][39] which are commonly used in the resistive PSs are known to exhibit significant sensitivity to temperature arising from their thermoresistive characteristics. [26,40] This paper is dedicated to developing flexible, all resistive multifunctional sensors which can simultaneously detect and discriminate temperature and pressure stimuli in real time, using carbon nanofiber (CNF) films as the sole sensing material.…”