“Self-Corralling” Nanorods under an Applied Electric Field

Abstract

Producing densely packed arrays of nanoscopic anisotropic objects, while necessary for applications in photovoltaic and field emission devices, presents considerable challenges. Here, we present findings on the phase separation of ligand-functionalized nanorods in a polymer matrix under an applied electric field. Densely packed hexagonal arrays of nanorods are produced by this method, where the rods are oriented in the direction of the applied field. Minimization of interfacial energy between the array of nanorods and the surrounding polymer serves to corral the nanorods into the densely packed arrays observed. These findings carry implications toward advancing organic-inorganic heterojunction photovoltaic devices that are expected to benefit from the oriented, densely packed ordered arrays of nanorods produced here.

Gold tip formation on perpendicularly aligned semiconductor nanorod assemblies

“…Monodisperse nanorods can be aligned into perpendicular arrays either by trapping a solution of the nanorods under an 5 electric field of 1kV or by pinning the nanorod solution between a Highly Oriented Pyrolytic Graphite block and a gold substrate according to previously published methods. [1][2][3] An optimized gold(I)chloride solution is spin cast onto the nanorods on a substrate for 30 seconds followed by a couple 10 of drops of methanol to quench the reaction. This procedure leads to the instantaneous and reproducible formation of an individual gold tip on the end of each nanorod in the array.…”

Nanofabrication for Molecular Scale Devices

“…The growth was triggered by ac electric fields exerting electrophoretic forces on the objects and this technique may be helpful in growing nanowires, provided that the electrodes are capable of shaping the electric field with the due precision. Finally, as carbon nanotubes and nanorods become increasingly important, methods are being studied to get them assembled in ordered geometries (Harnack et al, 2003;Gupta et al, 2006;Ryan et al, 2006;Nobile et al, 2007;Yan et al, 2007). Another interesting way of patterning might be that of exploiting the natural periodicity of crystals, which can be tuned to some extent by cutting the crystal to expose a particular face.…”

Polarized light emission by deposition of aligned semiconductor nanorods

“…Radial fluid flow with spin coating and drying lyotropic phase 1,15 , slow solvent evaporation at a liquid-solid-air interface 2,13 , coffee stain evaporation dynamic 14,16,17 , or external electric fields 18 , are some other techniques which are applied to align the NRs. Among them, aligned deposition of anisotropic particles from colloidal suspensions based on an applied alternating electric field is an efficient method for carbon nanotubes 19 , nanowires 20 , semiconductor 8,11,[21][22][23][24][25] The colloidal semiconductor NRs have an intrinsic dipole moment and a much higher dielectric constant than the apolar liquid. The NRs are subjected to random Brownian rotation.…”