Low-cost Copper Research Articles

Low-cost 13.56MHz Rectifier Based on Organic Diode

ABSTRACTIn this paper, low-cost rectifier based on an organic diode for use in organic radio frequency identification (RFID) tags is proposed. Pentacene is the electroactive layer, with 7,7,8,8-tetracyanoquinodimethane (TCNQ) modified low-cost copper (Cu) and aluminum (Al) as the Ohmic and Schottky contacts, respectively. Hole injection barrier between Cu and pentacene can be decreased by forming the self-assembled layers of Cu-TCNQ. The diode shows a high rectification ratio of approximately 2×106 at 5V and the organic diode based rectifier circuit generated a dc output voltage of approximately 2V at 13.56MHz, using an input ac signal with zero-to-peak voltage amplitude of 5 V. The results indicate that chemical modification of the low-cost electrodes could be an efficient way toward low-cost high performance organic electronics devices.

S-arylation of mercaptobenzimidazoles using Cu(I) catalysts—experimental and theoretical observations

Substituted 2-mercaptobenzimidazoles (MBI) are an important class of bio-active and industrially important organic compounds. In this Letter, a new synthetic method is presented for the selective S-arylation of MBI with substituted aryl iodides using low cost copper (I) iodide and 1,10-phenanthroline as a catalytic system. The selective formation of S-arylated product was confirmed by several spectroscopic techniques and the vibrational spectrum was found to be in very good agreement with the theoretical spectrum calculated by density functional theory.

Nanotextured Metal Copper Substrates as Powerful and Long-Lasting Fuel Cell Anodes

Fuel cells (FCs) are promising electrochemical devices that convert chemical energy of fuels directly into electrical energy. We present a new anode material based on nanotextured metal copper for fuel cell applications. We have demonstrated that low-cost copper catalyst anodes act as highly efficient and ultra-long-lasting materials for the direct electro-oxidation of ammonia-borane and additional amine derivatives. High power densities of ca. 1W·cm(-2) (ca. -1 V vs Ag/AgCl at 1 A) are readily achieved at room temperature. We fabricate fuel cell devices based on our nanotextured Cu anodes in combination with commercial air cathodes.

Cost efficient master fabrication process on copper substrates

In this work a rapid and low cost process for master fabrication was carried out. Thick epoxy SU-8 photoresist was employed as sacrificial patternable layer for the definition of metal deposition area. An SU-8 photolithographic recipe was employed on low cost copper substrates, without the use of a seed layer. In particular an improvement of SU-8 adhesion, for structures with 7:1 aspect ratio, was obtained. This process was characterized by Field Emission Scanning Electron Microscope analysis on metallic substrates and it was compared with other UV-LIthographie Galvanoformung Abformung processes. An electrolytic Cu deposition was used to fabricate the master and, since the metal was deposited directly onto the copper substrate, the simplified LIGA-like process did not require silicon substrate removal or mechanical polishing. Hence, the fabrication steps and process time were considerably decreased. Finally, different molds with microfluidic patterns for hot embossing replication were obtained in 24h with a significant costs reduction.

Photonic Curing Explanation and Application to Printing Copper Traces on Low Temperature Substrates

Photonic curing is a transient thin-film thermal processing technique using flashlamps. It was developed by NovaCentrix® and incorporated in the PulseForge® toolset to address the need of the printed electronics industry to process high temperature materials on low temperature substrates such as paper and plastic on a moving web. Applications include photovoltaics, displays, solid state lighting, thin film batteries, RFID tags, and printed circuits. The ability to substitute inexpensive and flexible substrates for expensive, rigid substrates while achieving similar performance can dramatically reduce the cost of the final product and enable new products. In this paper, we discuss the technology and mechanisms of the process and illustrate a case study of forming copper traces on plastic and paper in a roll-to-roll environment. Here, a low cost copper oxide ink is printed on plastic or paper and chemically reacted using pulsed light from the PulseForge tool to form highly conductive copper traces. This process is performed in an ambient atmosphere.

Effect of a SiNx insulator on device properties of pentacene-TFTs with a low-cost copper source/drain electrode

We fabricated different SiNx insulators at a 150–350 °C deposition temperature by plasma-enhanced chemical vapor deposition (PECVD) and investigated the effect of SiNx insulator on the device properties of pentacene-TFTs with a low-cost copper source/drain electrode. A pentacene-TFT with a SiNx insulator at a deposition temperature of 300 °C exhibited the highest saturation mobility of 0.29 cm2 (V s)−1, the lowest threshold voltage of −8.9 V and an on/off current ratio of 5.3 × 106. The best performance of the device with a SiNx insulator at a 300 °C deposition temperature can be attributed to the electrical properties and a relatively large water contact angle of insulator, smooth insulator surface and better crystallinity of the pentacene active layer. The present organic thin-film transistors (OTFTs) with the PECVD SiNx insulator and the low-cost Cu electrode could be a significant step toward the commercialization of OTFT technology.

MoO x interlayer to enhance performance of pentacene-TFTs with low-cost copper electrodes

We demonstrated that the electrical properties of pentacene-thin film transistors with low-cost Cu electrodes can be enhanced by inserting a thin MoO x interlayer layer between pentacene and Cu source/drain (S/D) electrodes. In comparison with the device having Cu-only electrodes, the performance of the device with MoO x /Cu electrodes was significantly improved. The saturation mobility increased from 0.13 to 0.61 cm 2/V s, threshold voltage reduced from −14.5 to −7.3 V, on/off ratio shifted from 8.9 × 10 5 to 1.6 × 10 6 and threshold swing varied from 1.92 to 1.33 V/decade. The improvement was attributed to the reduction of contact resistance and the enhancement of hole-injection efficiency. The results suggest modification of Cu S/D electrodes is a simple and effective way to improve device performance and reduce the fabrication cost.

Comparison of steam and autothermal reforming of methanol using a packed-bed low-cost copper catalyst

Small-scale reformers for hydrogen production via steam and autothermal reforming of hydrocarbon feedstocks can be a solution to the lack of hydrogen distribution infrastructure. A packed-bed reactor is one possible design for such purpose. However, the two reforming processes of steam and autothermal methods have different characteristics, thus they have different and often opposite design requirements. In implementing control strategy for small-scale reformers, understanding the overall chemical reactions and the reactor physical properties becomes essential. This paper presents some inherent features of a packed-bed reactor that can both improve and/or degrade the performance of a packed-bed reactor with both reforming modes.

Electrodeposited porous and amorphous copper oxide film for application in supercapacitor

In present study, the porous amorphous copper oxide thin films have been deposited from alkaline sulphate bath. The cathodic electrodeposition method was employed to deposit copper oxide film at room temperature on stainless steel substrate. Their structural and surface morphological properties were investigated by means of X-ray diffraction (XRD) and scanning electron micrograph (SEM), respectively. To propose this as a new material for possible application in the supercapacitor, its electrochemical properties have been studied in aqueous 1 M Na 2SO 4 electrolyte using cyclic voltammetry. The structural analysis from XRD pattern showed the formation of amorphous copper oxide film on the substrate. The surface morphological studies from scanning electron micrographs revealed the formation of porous cauliflower-like copper oxide film. The cyclic voltammetric curves showed symmetric nature and increase in capacitance with increase in film thickness. The maximum specific capacitance of 36 F g −1 was exhibited for the 0.6959 mg cm −2 film thickness. This shows that low-cost copper oxide electrode will be a potential application in supercapacitor.

Recent developments in aqueous processing

More than fi fty years have elapsed since the Sherritt–Gordon ammonia pressureoxygen-leaching process for nickel sulfi de fl otation concentration was developed in the 1950s. In the intervening time, dramatic new technologies in hydrometallurgy have transpired. The application of the solvent extractants for copper in leaching-SX–EW process is now commonplace, activated carbon technology has been implanted in gold recovery processing, and heap leaching is widely used to extract copper and gold from low-grade materials. Over the last three decades hydrometallurgical processing of chalcopyrite concentrates has received considerable attention because of interests that include environmental aspects and the possibility of increased exploitation of mixedand lower-grade ores. There has been a worldwide upsurge of hydrometallurgical process interests for the production of copper. Cuprous hydrometallurgical methods of reducing chalcopyrite were well studied by A.J. Parker and colleagues in 1980. Although it was on a laboratory scale within a non-aqueous process, the remarkable fi nding of factors that affect the rate and effi ciency of chalcopyrite dissolution still has merit in today’s R&D projects. A process that also deserves merit is the in-situ mining method using a dilute sulfuric acid for a deep copper-oxide deposit was developed by the former U.S. Bureau of Mines in 1986 and could lead to future innovative and low-cost copper mining methods. Recent Developments in Aqueous Processing

High‐Performance Organic Field‐Effect Transistors with Low‐Cost Copper Electrodes

High‐Performance Organic Field‐Effect Transistors with Low‐Cost Copper Electrodes

Efficient electrophosphorescence from low-cost copper(I) complex

Light-emitting devices, using a high-phosphorescent copper(I) complex [Cu(phen)(POP)]PF 6 [POP = Bis-[(2-diphenyl-phosphino)phenyl]ether and phen = 1,10-phenanthroline] as dopant and emitting center have been investigated, in different device architectures involving single layer devices using the blend of poly( N-vinylcarbazole) (PVK) and 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazol (PBD) as host and heterostructure multi layer devices using PVK as host. The maximum luminance of the phosphorescent devices reached 1400 cd/m 2 and the highest luminance efficiency exceeded 1 cd/A for single layer devices and higher luminescence efficiency up to 1.8 cd/A for multi layer ones. Efficient electrophosphorescent OLEDs can be developed by using low-cost Cu(I) complex as guest and polymer as host material.

A Study on the Metal Organic CVD of Pure Copper Films from Low Cost Copper(II) Dialkylamino‐2‐propoxides: Tuning the Thermal Properties of the Precursor by Small Variations of the Ligand

AbstractPure copper metal thin films were grown on SiO2/Si(100) substrates by metal–organic (MO) CVD in a horizontal cold‐wall reactor employing the two metal–organic compounds, Cu(OCHMeCH2NR2)2, where R = Et (1) and R = Me (2) as precursors. Thermogravimetric analyses proved them to be convenient compounds for the deposition of copper without a reducing agent. Depositions were carried out at various substrate temperatures in the range 230–350 °C. X‐ray diffraction (XRD) indicated that the resulting films were highly crystalline and showed a strong (111) preferred orientation, which increased with increasing deposition temperature. Photoelectron spectroscopy (XPS) revealed that copper films deposited at 230 °C and 260 °C consisted solely of metallic copper with no detectable carbon, nitrogen, or oxygen contamination. Copper films obtained from 1 at 260 °C had a resistivity of 2.16 μΩ cm.

Supergene Oxidation of Copper Deposits: Zoning and Distribution of Copper Oxide Minerals

ABSTRACT Copper oxides represent an attractive exploration target because even low-grade prospects have the potential to produce low-cost copper in an environmentally friendly fashion. Derived from liypogene and/or supergene sulfides, copper oxides comprise a series of distinct assemblages that characterize a variable pH. oxidizing geochemical environment known as “the oxide zone.” Development of oxide copper minerals is a function of source-rock and host-rock mineralogy, pyrite and other (copper) sulfide abundance and distribution, fracture density and distribution, phreatic and/or vadose zone occurrence and stability, and maturity of the weathering profile The paragenesis оf copper oxide mineral formation reflects local, dynamic changes in supergene solution composition attributable to reaction between host-rock mineral components and dissolved species Especially important are the concentrations of because mineral assemblages, even those that are metastable. represent the geochemical environment in which they formed, identification and mapping of copper oxides is useful in interpreting the geochemical history of an oxide zone. Furthermore, practical application of oxide zone geochemistry is significant in the recognition and solution of problems associated with weathering-engendered metals oxidation and transport from mine wastes.

Toward a New Iron Age? Quantitative Modeling of Resource Exhaustion.

Experts agree that the earth will eventually run out of certain low-cost, nonrenewable resources, possibly as early as a century from now. Will the transition to reliance on other, more abundant resources be smooth or discontinuous? Might industrial societies experience a marked decline in living standards a radically different kind of society from the one we now know? Geologists maintain that once inexpensive high-grade resources are exhausted, economic growth will slow. Economists are more optimistic: they believe that new technologies and materials will be substituted rapidly enough to prevent minor economic dislocations.Toward a New Iron Age? takes an important step toward reconciling these divergent views. It is the most comprehensive study of the economic consequences of resource depletion in particular, it is a thorough exploration of the prospects for one key metal, copper. The authors draw on geological and engineering data to calculate the resources now available and to assess the feasibility of substituting alternatives. Using linear programming and a range of hypothetical base conditions, they are able to estimate the course, through the next century and beyond, of several crucial factors: the rate at which copper resources will be used and when they will be depleted; how the price of the metal will fluctuate; when alternative materials will be substituted, in what patterns, and at what costs. By the late twenty-first century, the authors believe, low-cost copper will no longer be available. Industrial societies will have to operate on more abundant resources such as iron, silica, and aluminum. They will enter, in short, a New Iron Age.