Gold Nanoparticle in Chemoelectronics: Fundamentals, Challenges, and Future Prospects

Abstract

The basic components of modern electronics are primarily fabricated by using semiconductor material in which the movement of charges can be electrically modulated. For metallic material, however, such modulation is almost impossible because of its field‐shielding characteristics, leading to insensitive response toward applied potentials. In this perspective, how to overcome this limitation of bulk metals (here, gold is taken as a particular example) is demonstrated by reducing the size to the nanoscale and functionalizing these nanogolds with charged molecules. The movement of mobile counterions within gold nanoparticle (AuNP) layers can generate charge gradients that feed back and control the motion of electrons which enables to design and fabricate several important components such as the diode, transistor, logic circuits, memristor, and various chemiresistive sensors. The assembly of AuNP electronic components and sensors gives rise to a new class of nanoparticle‐based “chemoelectronic” logic circuits that can sense, process, and ultimately report various chemical signals. The gas sensors are believed to be the most appropriate candidates for such integration as no solvent/solution is required and therefore, in the end, the combination of AuNP gas sensors and memristors is outlooked to achieve all‐gold‐nanoparticle in‐sensor computing for the development of future artificial olfactory.

Nonohmic Ionic Conductivity and Bulk Current Rectification in Nanoparticle Superlattices

“…Figure d shows the corresponding conductivities false( J̅ / E false) versus E . The range of electric fields under study (−0.2 to 0.2 V/nm) is within that typically used in electronic/chemoelectronic applications, − ,, and results from applying a large potential bias to a thin film. This range is also similar to that used in previous MD studies of transport in NPSLs. , On the other hand, it should be noted that these electric fields are around 6 orders of magnitude larger than those typically experienced by electrolytes in solid-state batteries; thus, the nonohmic behaviors discussed here are not relevant for such applications.…”

“…Figure 2a−c displays the magnitude of the ionic flux J ( ) for this system as a function of the magnitude of the applied electric field (E) for different lattice parameters (which are obtained by varying the length of the neutral block according Table 1). Figure 2d shows the corresponding conductivities J E ( / ) versus E. The range of electric fields under study (−0.2 to 0.2 V/nm) is within that typically used in electronic/chemoelectronic applications, [9][10][11][12]41,42 and results from applying a large potential bias to a thin film. This range is also similar to that used in previous MD studies of transport in NPSLs.…”

“…Nanoparticle superlattices (NPSLs), self-assembled materials composed of periodically organized nanoparticles, are the mesoscopic analogues of ionic and covalent crystals. − Over the past decade, these materials have attracted the attention of the scientific community because of their potential applications in photonics, − plasmonics, ,, and nanoelectronics. , NPSLs also find applications in recently developed areas of research, such as chemoelectronics ,, (the field devoted to the processing of chemical stimuli by logic circuits), iontronics (devices where electric currents are controlled by ion fluxes), and nanofluidics − (which studies fluid flows at the nanoscale and nanoporous membranes).…”

“…Ion transport has been previously studied in solid-state devices made of thin films of superlattices of charged NPs. − In those systems, ion fluxes create built-in electric fields in the material, which affect their electric conductivity. Ion conduction is also relevant in single-ion electrolytes composed of charged NPs and their monovalent counterions, without added salt. , Recently, charge- and size-selective transport, , and ion-current rectification have been demonstrated for free-standing superlattices of charged NPs in contact with an electrolyte solution.…”

A Diffusive Artificial Synapse Based on Charged Metal Nanoparticles

“…In addition, this analogue device is set-step free (vs the digital one), highly efficient in terms of energy consumption, and tolerant of constant mechanical deformation and has tunable conductance modulation capabilities in terms of the degree of deprotonation of ligand molecules. Importantly, these gold nanoparticles can transduce various physical, chemical, and biochemical stimuli into electrical signals, which suggests a very promising computing paradigm in which sensing and processing are implemented in a single device. − The metal nanoparticle diffusive memristor is subsequently used to emulate several basic synaptic functions and build memristive operators for edge extraction.…”