Region‐Selective Deposition of Core–Shell Nanoparticles for 3 D Hierarchical Assemblies by the Huisgen 1,3‐Dipolar Cycloaddition

Abstract

A method for the region-selective deposition of nanoparticles (NPs) by the Huisgen 1,3-dipolar cycloaddition is presented. The approach enables defined stacking of various oxide NPs in any order with control over layer thickness. Thereby the reaction is performed between a substrate, functionalized with a self-assembled monolayer of an azide-bearing phosphonic acid (PA) and aluminum oxide (AlO(x)) NPs functionalized with an alkyne bearing PA. The layer of alkyne functionalized AlO(x) NPs is then used as substrate for the deposition of azide-functionalized indium tin oxide (ITO) NPs to provide a binary stack. This progression is then conducted with alkyne-functionalized CeO2 NPs, yielding a ternary stack of NPs with three different NP cores. The stacks are characterized by AFM and SEM, defining the region-selectivity of the deposition technique. Finally, these assemblies have been tested in devices as a dielectric to form a capacitor resulting in a dramatic increase in the measured capacitance.

Self‐Assembled Monolayers as Patterning Tool for Organic Electronic Devices

“…Also metal oxide nanoparticles (NPs) can be processed into micropatterns from solution, based on chemical interaction with the substrate surface. Recently, Etschel et al reported on an approach to functionalize aluminum oxide, cerium oxide, or ITO nanoparticles with either 10‐undecynylphosphonic acid or 12‐azidododecylphosphonic acid surfactants . At the same time, an aluminum oxide substrate was functionalized with a SAM‐pattern of an azide‐terminated SAM in a SAM‐matrix of a fluorinated phosphonic acid.…”

“…b) Atomic force microscope images of a single particle layer, a double layer and three layers of different metal oxide nanoparticles, as well as the corresponding height profiles. Reprinted with permission . Copyright 2015 Wiley‐VCH.…”

Green Processing of Metal Oxide Core–Shell Nanoparticles as Low‐Temperature Dielectrics in Organic Thin‐Film Transistors

“…In contrast to bulk oxide dielectric layers, the NP‐based layers differ in their composition. Considering the core‐shell architecture, which provides different ε‐values for core and shell materials, and the particulate structure leading to a certain porosity of the layer, the measured capacitances of the NP layers are larger than those formed from bulk oxide …”

Highly Efficient Encapsulation and Phase Separation of Apolar Molecules by Magnetic Shell‐by‐Shell‐Coated Nanocarriers in Water

“…Studies on metal nanoparticles, predominantly gold or silver, indicate that the nanoparticle–molecule interface is not rigid but dynamic, to some extent . This is especially important for the formation of mixed‐ligand shells that can be obtained either by direct synthesis, ligand exchange, or postfunctionalization . On oxide nanoparticles, this interface chemistry is significantly less understood than for metals.…”

“…Since the oxide core provides intrinsic properties as superparamagnetism, photocatalytical, and photovoltaic activity or the color, the interaction between the particles and the environment is strongly determined by the NP surface . Covalently bonded monolayers of surface active molecules lead to core–shell nanoparticles, whereby the nature of the shell molecules enable a fine tuning of the NP dispersibility, the improvement of biocompatibility or they guide the assembly of such hybrids to 3D‐architectures …”