title: Chemoelectronic circuits based on metal nanoparticles.
abstract: To develop electronic devices with novel functionalities and applications, various non-silicon-based materials are currently being explored. Nanoparticles have unique characteristics due to their small size, which can impart functions that are distinct from those of their bulk counterparts. The use of semiconductor nanoparticles has already led to improvements in the efficiency of solar cells, the processability of transistors and the sensitivity of photodetectors, and the optical and catalytic properties of metal nanoparticles have led to similar advances in plasmonics and energy conversion. However, metals screen electric fields and this has, so far, prevented their use in the design of all-metal nanoparticle circuitry. Here, we show that simple electronic circuits can be made exclusively from metal nanoparticles functionalized with charged organic ligands. In these materials, electronic currents are controlled by the ionic gradients of mobile counterions surrounding the 'jammed' nanoparticles. The nanoparticle-based electronic elements of the circuitry can be interfaced with metal nanoparticles capable of sensing various environmental changes (humidity, gas, the presence of various cations), creating electronic devices in which metal nanoparticles sense, process and ultimately report chemical signals. Because the constituent nanoparticles combine electronic and chemical sensing functions, we term these systems 'chemoelectronic'. The circuits have switching times comparable to those of polymer electronics, selectively transduce parts-per-trillion chemical changes into electrical signals, perform logic operations, consume little power (on the scale of microwatts), and are mechanically flexible. They are also 'green', in the sense that they comprise non-toxic nanoparticles cast at room temperature from alcohol solutions.
authors.affiliation: CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Yan
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA.|Department of Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3216, USA.
authors.forename: Scott C
authors.initials: SC
authors.lastname: Warren
authors.affiliation: NuMat Technologies, Skokie, Illinois 60077, USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Fuller
authors.affiliation: IBS Center for Soft and Living Matter and the Department of Chemistry, UNIST, Ulsan, South Korea.
authors.forename: Bartosz A
authors.initials: BA
authors.lastname: Grzybowski