Topologically Controlled Growth of Magnetic-Metal-Functionalized Semiconductor Oxide Nanorods

Abstract

Colloidal semiconductor-magnetic hybrid nanocrystals with topologically controlled composition are fabricated by heterogeneous nucleation of spherical epsilon-Co domains onto anatase TiO2 nanorods. The latter can be selectively decorated at either their tips or at multiple locations along their longitudinal sidewalls, forming lattice-matched heterointerfaces regardless of the metal deposition sites. The possibility of switching between either heterostructure growth modes arises from the facet-dependent chemical reactivity of the oxide seeds, which is governed mainly by selective adhesion of the surfactants rather than by small differences in misfit-induced interfacial strain at the relevant junction points.

Colloidal magnetic nanocrystal clusters: variable length-scale interaction mechanisms, synergetic functionalities and technological advantages

“…Single-crystal inorganic magnetic nanoparticles (henceforth, nanocrystals) have attracted increasing attention in the recent years due to their unique applications in various fields, including magnetic storage [1], electronics [2], solar energy conversion [3,4], plasmonics [5], medical diagnosis [6], and therapy [7]. The magnetic nanocrystals are an appealing subject of study because they exhibit a vastly different physical behavior from that in their bulk counterparts [8].…”

Controlled Fabrication of Colloidal Semiconductor–Metal Hybrid Heterostructures: Site Selective Metal Photo Deposition

“…18 Similarly, metal nanoparticle deposition along the whole length of semiconductor nanorods has been demonstrated for CdSÀAu, 16,27 CdSe/CdSÀAu, 19 CdSeÀPt, 28 CdSÀPdO and CdSÀPd 4 S, 24 CdSÀPt, 29 CdSe/CdSÀPt, 29 CdSÀFePt, 30 and a-TiO 2 ÀCo. 26 Other reports include CdSe nanowires decorated with Au, Pt, PtCo, and PtNi nanoparticles, 31 PbS nanocubes coated with Au nanoparticles, 32 and nanoporous CdS loaded with Pt nanoparticles. 33 Some of these reports build upon earlier work on the surface modification of microcrystalline semiconductors using platinum group metals as a way to generate hydrogen evolving photocatalysts, for example, CdSÀPt doped wth Zn and Ag sulfides, 34,35 and powders made of MS/CdS/M(M = Pt, Ir), 36 ABSTRACT: Reliable synthesis of semiconductorÀmetal heterostructures would increase their availability for fundamental studies and applications in catalytic, magnetic, and opto-electronic devices.…”

Colloidal Magnetic Heterostructured Nanocrystals with Asymmetric Topologies: Seeded-Growth Synthetic Routes and Formation Mechanisms

“…For example, selective heterogeneous nucleation may be viewed as being energetically convenient when it permits elimination of some unstable facets of the seeds (e.g., high-index facets, located, for example, at the apexes or edge regions of nanorods) at the proportionally smaller cost of the interfacial strain energy spent in the formation of the heterojunctions. However, when nucleation and growth occur under kinetically controlled regimes, and/or other chemical or physical transformative pathways come into play (e.g., intraparticle ripening, atomic diffusion, and ion exchange), thermodynamic predictions may not be verified and thus the comprehension of the mechanisms underlying topology selection may be far less straightforward Jun et al, 2006;Casavola et al, 2007Casavola et al, , 2008Wetz et al, 2007;Maynadiè et al, 2009;Costi et al, 2010;de Mello Donegà, 2011;Banin et al, 2014).…”