해외산업간호정보 - 미국 산업안전보건연구원(National Institute for Occupational Safety and Health) 소개

Silver nanowires (AgNWs) surrounded by insulating poly(vinylpyrrolidone) have been synthesized by a polyol process and employed as transparent electrodes. The AgNW transparent electrodes can be fabricated by heat-treatment at about 200 °C which forms connecting junctions between AgNWs. Such a heating process is, however, one of the drawbacks of the fabrication of AgNW electrodes on heat-sensitive substrates. Here it has been demonstrated that the electrical conductivity of AgNW electrodes can be improved by mechanical pressing at 25 MPa for 5 s at room temperature. This simple process results in a low sheet resistance of 8.6 Ω/square and a transparency of 80.0%, equivalent to the properties of the AgNW electrodes heated at 200 °C. This technique makes it possible to fabricate AgNW transparent electrodes on heat-sensitive substrates. The AgNW electrodes on poly(ethylene terephthalate) films exhibited high stability of their electrical conductivities against the repeated bending test. In addition, the surface roughness of the pressed AgNW electrodes is one-third of that of the heat-treated electrode because the AgNW junctions are mechanically compressed. As a result, an organic solar cell fabricated on the pressed AgNW electrodes exhibited a power conversion as much as those fabricated on indium tin oxide electrodes. These findings enable continuous roll-to-roll processing at room temperature, resulting in relatively simple, inexpensive, and scalable processing that is suitable for forthcoming technologies such as organic solar cells, flexible displays, and touch screens. Open image in new window

Fabrication of silver nanowire transparent electrodes at room temperature

Due to their unique physicochemical properties, graphene-family nanomaterials (GFNs) are widely used in many fields, especially in biomedical applications Currently, many studies have investigated the biocompatibility and toxicity of GFNs in vivo and in intro Generally, GFNs may exert different degrees of toxicity in animals or cell models by following with different administration routes and penetrating through physiological barriers, subsequently being distributed in tissues or located in cells, eventually being excreted out of the bodies This review collects studies on the toxic effects of GFNs in several organs and cell models We also point out that various factors determine the toxicity of GFNs including the lateral size, surface structure, functionalization, charge, impurities, aggregations, and corona effect ect In addition, several typical mechanisms underlying GFN toxicity have been revealed, for instance, physical destruction, oxidative stress, DNA damage, inflammatory response, apoptosis, autophagy, and necrosis In these mechanisms, (toll-like receptors-) TLR-, transforming growth factor β- (TGF-β-) and tumor necrosis factor-alpha (TNF-α) dependent-pathways are involved in the signalling pathway network, and oxidative stress plays a crucial role in these pathways In this review, we summarize the available information on regulating factors and the mechanisms of GFNs toxicity, and propose some challenges and suggestions for further investigations of GFNs, with the aim of completing the toxicology mechanisms, and providing suggestions to improve the biological safety of GFNs and facilitate their wide application

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Toxicity of graphene-family nanoparticles: a general review of the origins and mechanisms

The need for high power density and high temperature capabilities in today's electronic devices continues to grow. More robust devices with reliable and stable functioning capabilities are needed, for example in aerospace and automotive industries as well as sensor technology. These devices need to perform under extreme temperature conditions, and not show any deterioration in terms of switching speeds, junction temperatures, and power density, and so on. While the bulk of research is performed to source and manufacture these high temperature devices, the device interconnect technology remains under high focus for packaging. The die attach material has to withstand high temperatures generated during device functioning and also cope with external conditions which will directly determine how well the device performs in the field. This literature work seeks to review the numerous research attempts thus far for high temperature die attach materials on wide band gap materials of silicon carbide, gallium nitride and diamond, document their successes, concerns and application possibilities, all of which are essential for high temperature reliability.

Die Attach Materials for High Temperature Applications: A Review

Graphene and its derivatives are heralded as ‘miracle’ materials with manifold applications in different sectors of society from electronics to energy storage to medicine. The increasing exploitation of graphene-based materials (GBMs) necessitates a comprehensive evaluation of the potential impact of these materials on human health and the environment. Here we discuss synthesis and characterization of GBMs as well as human and environmental hazard assessment of GBMs using in vitro and in vivo model systems with the aim to understand the properties that underlie the biological effects of these materials; not all GBMs are alike, and it is essential that we disentangle the structure-activity relationships for this class of materials.

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Keun-Soo Kim

Papers

Effects of intermetallic compounds on properties of Sn–Ag–Cu lead-free soldered joints

High-Temperature Lead-Free Solders: Properties and Possibilities

Effects of fourth alloying additive on microstructures and tensile properties of Sn–Ag–Cu alloy and joints with Cu

Low-temperature low-pressure die attach with hybrid silver particle paste

Effect of composition and cooling rate on microstructure and tensile properties of Sn–Zn–Bi alloys