Self assembled nanoparticle wires by discontinuous vertical colloidal deposition

Abstract

We report a simple, one-step method for assembling spherical nanoparticles into wires without the need for lithographic templating. It is effective for a variety of conducting and nonconducting nanoparticles and substrates, and the only material requirement is that the nanoparticles be placed in a colloidal suspension that is wettable on the desired substrate. The shape of the meniscus defines the wire's geometry, and we report the synthesis and physical properties of wires several millimeters long by a few micrometers wide. As we demonstrate here, the technique is fast and easily controlled, and can be used to make integrated nanoparticle wire arrays.

Pt/CdTe/Pt asymmetric nano-Schottky diodes from colloidal quantum dots

“…The coffee-ring effect has been manifested previously in various systems with diverse constituents, ranging from large colloids to nanoparticles and individual molecules. [16][17][18][19][20][21][22] Figure 2 current in the applied voltage range. For a Schottky diode, the I-V relation can be expressed as…”

Gold nanoparticle wire and integrated wire array for electronic detection of chemical and biological molecules

“…Various deposition times result the wire width ranging from several to hundred micrometers with a 100 nm thickness. 21 Since the conductance of porous gold nanoparticle wires made by discontinuous VECD is influenced by the local environment, 21,25 these conducting nanoparticle wires are promising to use in sensitive electric detections for chemical and biological objects because of the high surface to volume ratio. To test this, similar gold nanoparticle wires were painted with gold electrodes by the electron beam evaporator (Teme scasl BJD1800), and then measured by a semiconductor parameter analyzer (HP 4155A) or a lock-in amplifier (Signal Recovery 7265) through a probe station system.…”

“…21 The wire is formed along their width direction, and the width is determined by the evaporation rate and the deposition time: speeds of hundred nanometers per second and times of several seconds to minutes. 21 The repetition of this process forms parallel nanoparticle wires on the substrate. After being deposited a layer of parallel wires, the substrate is removed from suspension, rotated by an angle, and reimmersed.…”

“…15,16 Most recently, substantial amount of techniques with advantages over others with respect to simplicity, scale, resolution, and cost, have been developed to make one-dimensional (1D) nanoparticle structures. [17][18][19][20][21][22][23][24] In this paper, conducting gold nanoparticle wire and integrated wire array made by discontinuous Vertical Evaporation-driven Colloidal Deposition (VECD) are used for chemical and biological detections. Due to the high surface to volume ratio, these porous nanoparticle structures show a potential usage for the highly sensitive electric detection, as well as the localized detection.…”

Toward Greener Nanosynthesis

“…A wide range of substrates may be used as supports for assembled nanoparticles, ranging from simple planar substrates such as glass (including the SiO 2 windows of novel TEM grids, see Figure 34), silicon wafers, and gold, 90,243,281,284,293,294,297 to interfacial substrates found at the liquid-liquid and liquid-gas boundaries, [298][299][300][301][302][303][304][305][306] to more exotic supports such as biomolecules.…”