Templating growth of gold nanostructures with a CdSe quantum dot array

Abstract

In optoelectronic devices based on quantum dot arrays, thin nanolayers of gold are preferred as stable metal contacts and for connecting recombination centers. The optimal morphology requirements are uniform arrays with precisely controlled positions and sizes over a large area with long range ordering since this strongly affects device performance. To understand the development of gold layer nanomorphology, the detailed mechanism of structure formation are probed with time-resolved grazing incidence small-angle X-ray scattering (GISAXS) during gold sputter deposition. Gold is sputtered on a CdSe quantum dot array with a characteristic quantum dot spacing of ≈7 nm. In the initial stages of gold nanostructure growth, a preferential deposition of gold on top of quantum dots occurs. Thus, the quantum dots act as nucleation sites for gold growth. In later stages, the gold nanoparticles surrounding the quantum dots undergo a coarsening to form a complete layer comprised of gold-dot clusters. Next, growth proceeds dominantly via vertical growth of gold on these gold-dot clusters to form an gold capping layer. In this capping layer, a shift of the cluster boundaries due to ripening is found. Thus, a templating of gold on a CdSe quantum dot array is feasible at low gold coverage.

Catalytic Gold Deposition for Ultrasensitive Optical Immunosensing of Prostate Specific Antigen

“…In a recent study, the controlled catalytic deposition of Au(III) ions was investigated in order to enhance the scattering light produced for AuNPs to detect low abundant target in transparent tissues using confocal microscopy [ 15 ]. The catalytic deposition of silver on CdSe/ZnS QDs or on AuNPs [ 23 ] have been also reported for quantitative purposes. Silver amplification has been demonstrated to be a simple and fast process but with low reproducibility owing to the difficulty in controlling the kinetic process that occurs during the amplification step [ 16 ].…”

“…Silver amplification has been demonstrated to be a simple and fast process but with low reproducibility owing to the difficulty in controlling the kinetic process that occurs during the amplification step [ 16 ]. In this regard, gold amplification on the surface of different NPs has also been evaluated [ 23 , 25 , 26 ]: Unlike silver amplification, gold deposition was demonstrated to be more effective and reproducible [ 16 ].…”

“…AuNP immunoprobes were prepared following a previously reported procedure with some few modifications [ 23 ]. Briefly, the AuNPs solution was adjusted to pH 8.5 using NaOH 1 M, and then the solution was incubated with a solution of monoclonal antibody anti-PSA using a molar ratio 1:1 (AuNPs:Ab) for 1 h at 4 °C.…”

Off-Resonance Control and All-Optical Switching: Expanded Dimensions in Nonlinear Optics

“…The prospect we have identified of controlling resonance energy transfer without requiring a microcavity [120] is most likely to involve all-optical switching implemented in a synthetic heterostructure. Building such a device requires exploitation of the recent advances in the construction of quantum dot arrays-see, for example, [121,122]-here, with juxtaposed arrays sandwiching an optically transparent spacer layer. Technical realizations are expected to implement the most suitable nanofabrication method, such as dip-pen nanolithography.…”

Layered hybrid phase Li2NaV2(PO4)3/carbon dot nanocomposite cathodes for Li+/Na+ mixed-ion batteries

“…On account of the high surface-to-mass ratio of CDs, much more lithium ions can be situated on the sites. [33][34][35] Based on the excellent physical properties of CDs such as quantum tunneling effect and high electron mobility, Li + ions and electrons transport efficiency was increased. 36,37 Moreover, the sheetlike carbon composites can signicantly accelerate the charge transfer rate.…”