S.G. Hardin

Photoluminescence enhancement of carbon dots by gold nanoparticles conjugated via PAMAM dendrimers

Carbon dots (CDs) have many fascinating fluorescent properties, however, their low quantum yield limits their applications. In this study, the photoluminescence (PL) of CDs in the vicinity of gold nanoparticles (Au NPs) is enhanced significantly due to the surface plasmon resonance (SPR) of the Au NPs. This is achieved by conjugating Au NPs and CDs to dendrimers (PAMAM) through an amidation reaction, resulting in the formation of the Au-PAMAM-CD conjugates. The maximum 62-fold enhancement was obtained with an optimized molar ratio between Au NPs, PAMAM, and CDs. In this process, PAMAM, which serves as a spacer, can keep Au NPs and CDs at an appropriate distance for PL enhancement. The adjustment of the amount of Au NPs or CDs linked to PAMAM can induce the optimum PL enhancement. This strategy can be easily applied to different metal-space-fluorophore systems to enhance the fluorescence of fluorophores.

Interaction of Ce(dbp)3 with surface of aluminium alloy 2024-T3 using macroscopic models of intermetallic phases

Abstract The mechanism of corrosion inhibition by cerium(III) dibutylphosphate [Ce(dbp)3] on aluminium alloy 2024-T3 (AA2024-T3) has been investigated using macroscopic models of the intermetallic (IM) phases in the alloy. Polished specimens of pure Al (99·999%) and the macroscopic IM phases Al2CuMg, Al7Cu2Fe and Al3Fe were each coupled to a large surface area of AA2024-T3 to simulate the interaction they experience in the alloy. Samples were immersed in 0·1M NaCl with 200 ppm Ce(dbp)3 for 24 h, and the resulting surfaces characterised by scanning electron microscopy, X-ray photoelectron spectroscopy, Rutherford backscattering spectroscopy and Raman spectroscopy. Ce(dbp)3 was found to interact differently with each of the different phases examined, providing evidence for a multifunctional corrosion inhibition mechanism.

Progress towards preparation of high-surface-area rare-earth oxides

A series of high-surface-area rare-earth oxides has been prepared by precipitation from aqueous solution as either the hydroxide or the carbonate, followed by controlled dehydration, acetone washing, vacuum drying and calcination at ca. 600 °C. The materials have been characterised by X-ray diffraction (XRD), transmission electron microscopy (TEM), infrared spectroscopy (IR) and surface analysis. Precipitation by hydroxide produces a higher surface area for the lighter rare earths, whereas precipitation by carbonate is superior for the heavier members. By judicious choice of method, pure oxides (containing only trace amounts of surface carbonate) with surface areas > 50 m2 g–1 can be obtained for all rare earths studied. No microporosity was observed in any of the oxides.

Light Olefins From Synthesis Gas Using Ruthenium on Rare Earth Oxide Catalysts

Abstract The interaction of ruthenium carbonyl, Ru 3 (CO) 12 with rare earth oxides of high surface area, >50m 2 g −1 , has been studied. [Ru 3 (μ H)(CO) 10 (μ-OM≡)] is formed on holmia, but on lanthana only [Ru(CO) 2 ] n species are observed. Reduction of the carbonyl ligands takes place at

Nano-scale reservoir computing

This work describes preliminary steps towards nano-scale reservoir computing using quantum dots. Our research has focused on the development of an accumulator-based sensing system that reacts to changes in the environment, as well as the development of a software simulation. The investigated systems generate nonlinear responses to inputs that make them suitable for a physical implementation of a neural network. This development will enable miniaturisation of the neurons to the molecular level, leading to a range of applications including monitoring of changes in materials or structures. The system is based around the optical properties of quantum dots. The paper will report on experimental work on systems using Cadmium Selenide (CdSe) quantum dots and on the various methods to render the systems sensitive to pH, redox potential or specific ion concentration. Once the quantum dot-based systems are rendered sensitive to these triggers they can provide a distributed array that can monitor and transmit information on changes within the material.