Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology.

Cerium dioxide (CeO2, ceria) is becoming an ubiquitous constituent in catalytic systems for a variety of applications. 2016 sees the 40th anniversary since ceria was first employed by Ford Motor Company as an oxygen storage component in car converters, to become in the years since its inception an irreplaceable component in three-way catalysts (TWCs). Apart from this well-established use, ceria is looming as a catalyst component for a wide range of catalytic applications. For some of these, such as fuel cells, CeO2-based materials have almost reached the market stage, while for some other catalytic reactions, such as reforming processes, photocatalysis, water-gas shift reaction, thermochemical water splitting, and organic reactions, ceria is emerging as a unique material, holding great promise for future market breakthroughs. While much knowledge about the fundamental characteristics of CeO2-based materials has already been acquired, new characterization techniques and powerful theoretical methods are dee...

Fundamentals and Catalytic Applications of CeO2-Based Materials

Nearing 30 years since its introduction, 3D printing technology is set to revolutionize research and teaching laboratories. This feature encompasses the history of 3D printing, reviews various printing methods, and presents current applications. The authors offer an appraisal of the future direction and impact this technology will have on laboratory settings as 3D printers become more accessible.

https://www.egr.msu.edu/eceshop/testingfacility/connex/papers/ac403397r.pdf

Evaluation of 3D printing and its potential impact on biotechnology and the chemical sciences.

Inkjet printing is an attractive patterning technology, which has become increasingly accepted for a variety of industrial and scientific applications. This review primarily presents an overview of the investigations that have been conducted since 2003 into inkjet-printing polymers or metal-containing inks and mentions related activities. The first section discusses the droplet-formation process in piezoelectric drop-on-demand printheads and the physical properties that affect droplet formation and the resolution of inkjet-printed features. The second section deals with the issues that arise from printing polymers, such as printability and the output characteristics of devices made by this route. Finally, the challenges and achievements attached to inkjet printing metal-containing inks are discussed before concluding with a few remarks about the future of the field.

Inkjet printing as a deposition and patterning tool for polymers and inorganic particles

All-printed electronics is the key technology to ultra-low-cost, large-area electronics. As a critical step in this direction, we demonstrate that laser sintering of inkjet-printed metal nanoparticles enables low-temperature metal deposition as well as high-resolution patterning to overcome the resolution limitation of the current inkjet direct writing processes. To demonstrate this process combined with the implementation of air-stable carboxylate-functionalized polythiophenes, high-resolution organic transistors were fabricated in ambient pressure and room temperature without utilizing any photolithographic steps or requiring a vacuum deposition process. Local thermal control of the laser sintering process could minimize the heat-affected zone and the thermal damage to the substrate and further enhance the resolution of the process. This local nanoparticle deposition and energy coupling enable an environmentally friendly and cost-effective process as well as a low-temperature manufacturing sequence to realize large-area, flexible electronics on polymer substrates.

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All-inkjet-printed flexible electronics fabrication on a polymer substrate by low-temperature high-resolution selective laser sintering of metal nanoparticles

The radially oscillating flow hybrid cooling system, in the following referred to as RADIOS, provides a thin form factor cold plate with radial spreading of heat to a larger area. A small liquid volume (<10 ml) is hermetically sealed within the system and does not require external hose connections. Four membrane pumps running in a phase-delayed manner induce a constant-speed, oscillating direction fluid flow at the chip source that continuously shuttles heat to an extended periphery and returns cool liquid to the chip. In the peripheral branches, heat is transferred from the liquid to solid structures and finally dissipated to the air. A micro-scale copper mesh enables low-resistance heat transfer (solid-liquid and liquid- solid) in a thin form factor (< 2 mm). Narrow channels between the discrete heat exchanger areas optimize the spreading performance and reduce the fluid volume. Numerical modeling shows an effective conductivity of 20X and 50X over bulk copper for the spreader plates and the interconnecting tubes, respectively. The technology presented here promotes modular liquid cooling units for low-profile computing systems without incurring the risk of flooding associated with conventional liquid cooling circuits.

Radially Oscillating Flow Hybrid Cooling System for Low Profile Electronics Applications

Dropwise deposition and wetting of nanoparticle suspensions

A novel method for the manufacturing of electric microconductors for semiconductor and other devices is presented. The method brings together three technologies: controlled (on demand) printing, laser curing, and the employment of nanoparticles of matter, possessing markedly different properties (here, melting point) than their bulk counterparts. A suspension of gold particles in toluene solvent is employed to print electrically conducting line patterns utilizing a modified on demand ink jet printing process. To this end, microdroplets of 80–100 μm diameters are deposited on a moving substrate such that the droplets form continuous lines. Focused laser irradiation is utilized in order to evaporate the solvent, melt the metal nanoparticles in the suspension, and sinter the suspended particles to form continuous, electrically conducting gold microlines on a substrate. The ultra fine particles in the suspension have a diameter size range of 2 – 5 nm. Due to curvature effects of such small particles, the melting point is markedly lower (400°C) than that of bulk gold (1063°C). Thermodynamic aspects of the effect of particle size on the melting and evaporation temperatures of gold and toluene, respectively, are discussed in the paper. The structure and line width of the cured line as a function of the laser irradiation power and stage velocity are reported in detail. Preliminary measurements of the electrical conductivity are represented.Copyright © 2002 by ASME

Manufacturing of Electrically Conductive Microstructures by Dropwise Printing and Laser Curing of Nanoparticle-Suspensions

In this study, pulsed laser based curing of a printed nanoink (nanoparticle ink) combined with moderate and controlled substrate heating was investigated to create microconductors at low enough temperatures appropriate for polymeric substrates. The present work relies on (1) melting temperature depression of nanoparticles smaller than a critical size, (2) DOD (drop on demand) jettability of nanoparticle ink and (3) small heat affected zone of pulsed laser heating. In the experiment, gold nanoparticles of 3–7nm diameter dissolved in toluene solvent was used as ink. This nanoink was printed on a polymeric substrate which was heated to evaporate the solvent during or after printing. The overall morphology of the gold microline was determined during the printing process and was controlled by changing the substrate temperature during jetting. By employing a micro-second pulsed laser, the nanoparticles were melted and coalesced at a low temperature to form a conductive microline which has 4–5 times higher resistivity than the bulk value without damaging the temperature sensitive polymeric substrate.Copyright © 2004 by ASME

Nicole R. Bieri

Papers

Radially Oscillating Flow Hybrid Cooling System for Low Profile Electronics Applications

Dropwise deposition and wetting of nanoparticle suspensions

Manufacturing of Electrically Conductive Microstructures by Dropwise Printing and Laser Curing of Nanoparticle-Suspensions

Microconductors on Polymer by Nanoink Printing and Pulsed Laser Curing

Verfahren zur Herstellung einer Struktur unter Verwendung von Nanopartikeln