"Direct Writing" of diamond patterns from graphite a potential technological leap

A new technique uses a pulsing laser to create synthetic nanodiamond films and patterns from graphite, with potential applications from biosensors to computer chips.

"The biggest advantage is that you can selectively deposit nanodiamond on rigid surfaces without the high temperatures and pressures normally needed to produce synthetic diamond," said Gary Cheng, an associate professor of industrial engineering at Purdue University. "We do this at room temperature and without a high temperature and pressure chamber, so this process could significantly lower the cost of making diamond. In addition, we realize a direct writing technique that could selectively write nanodiamond in designed patterns."

The ability to selectively "write" lines of diamond on surfaces could be practical for various potential applications including biosensors, quantum computing, fuel cells and next-generation computer chips.

The technique works by using a multilayered film that includes a layer of graphite topped with a glass cover sheet. Exposing this layered structure to an ultrafast-pulsing laser instantly converts the graphite to an ionized plasma and creates a downward pressure. Then the graphite plasma quickly solidifies into diamond. The glass sheet confines the plasma to keep it from escaping, allowing it to form a nanodiamond coating.

"These are super-small diamonds and the coating is super-strong, so it could be used for high-temperature sensors," Cheng said.

This illustration depicts a new technique that uses a pulsing laser to create synthetic nanodiamond films and patterns from graphite, with potential applications from biosensors to computer chips. (Purdue University image/Gary Cheng

Nature Scientific Reports - Direct Laser Writing of Nanodiamond Films from Graphite under Ambient Conditions 


The researchers made the discovery while studying how to strengthen metals using a thin layer of graphite and a nanosecond-pulsing laser. A doctoral student noticed that the laser was either causing the graphite to disappear or turn semi-transparent.

"The black coating of graphite was gone, but where did it go?" Cheng said.

Subsequent research proved the graphite had turned into diamond. The Purdue researchers have named the process confined pulse laser deposition (CPLD).

The research team confirmed that the structures are diamond using a variety of techniques including transmission electron microscopy, X-ray diffraction and the measurement of electrical resistance.

Abstract

Synthesis of diamond, a multi-functional material, has been a challenge due to very high activation energy for transforming graphite to diamond, and therefore, has been hindering it from being potentially exploited for novel applications. In this study, we explore a new approach, namely confined pulse laser deposition (CPLD), in which nanosecond laser ablation of graphite within a confinement layer simultaneously activates plasma and effectively confine it to create a favorable condition for nanodiamond formation from graphite. It is noteworthy that due to the local high dense confined plasma created by transparent confinement layer, nanodiamond has been formed at laser intensity as low as 3.7 GW per square centimeter, which corresponds to pressure of 4.4 GPa, much lower than the pressure needed to transform graphite to diamond traditionally. By manipulating the laser conditions, semi-transparent carbon films with good conductivity (several kΩ per Sq) were also obtained by this method. This technique provides a new channel, from confined plasma to solid, to deposit materials that normally need high temperature and high pressure. This technique has several important advantages to allow scalable processing, such as high speed, direct writing without catalyst, selective and flexible processing, low cost without expensive pico/femtosecond laser systems, high temperature/vacuum chambers.

First Water-Based Nuclear Battery Can Be Used to Generate Electricity for decades with betavoltaics breakthrough

From cell phones to cars and flashlights, batteries play an important role in everyday life. Scientists and technology. companies constantly are seeking ways to improve battery life and efficiency. Now, for the first time using a water-based solution, researchers at the University of Missouri have created a long-lasting and more efficient nuclear battery that could be used for many applications such as a reliable energy source in automobiles and also in complicated applications such as space flight.

The battery uses a radioactive isotope called strontium-90 that boosts electrochemcial energy in a water-based solution. A nanostructured titanium dioxide electrode (the common element found in sunscreens and UV blockers) with a platinum coating collects and effectively converts energy into electrons.

“Water acts as a buffer and surface plasmons created in the device turned out to be very useful in increasing its efficiency,” Kwon said. “The ionic solution is not easily frozen at very low temperatures and could work in a wide variety of applications including car batteries and, if packaged properly, perhaps spacecraft.”

The maximum energy conversion efficiency of the MU battery was approximately estimated to be 53.88%. This is an astonishing number for a first trial design. Strontium 90 has a half life of 28.79 years

H/T to New Energy and Fuel

Nature Scientific Reports - Plasmon-assisted radiolytic energy conversion in aqueous solutions


ABSTRACT

The field of conventional energy conversion using radioisotopes has almost exclusively focused on solid-state materials. Herein, we demonstrate that liquids can be an excellent media for effective energy conversion from radioisotopes. We also show that free radicals in liquid, which are continuously generated by beta radiation, can be utilized for electrical energy generation. Under beta radiation, surface plasmon obtained by the metallic nanoporous structures on TiO2 enhanced the radiolytic conversion via the efficient energy transfer between plasmons and free radicals. This work introduces a new route for the development of next-generation power sources.


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Korea made graphene nickel composite that were up to 4 times stronger than Titanium

Nature - Korean researchers developed graphene copper composite material that is 50% stronger than titanium and a graphene nickel composite that is 4 times stronger than titanium. They demonstrated a new material design in the form of a nanolayered composite consisting of alternating layers of metal (copper or nickel) and monolayer graphene that has ultra-high strengths of 1.5 and 4.0 GPa for copper–graphene with 70-nm repeat layer spacing and nickel–graphene with 100-nm repeat layer spacing, respectively. The ultra-high strengths of these metal–graphene nanolayered structures indicate the effectiveness of graphene in blocking dislocation propagation across the metal–graphene interface. Ex situ and in situ transmission electron microscopy compression tests and molecular dynamics simulations confirm a build-up of dislocations at the graphene interface. The copper-graphene composite that has 500 times the tensile strength of copper (1.5 gigapascals), and a nickel-grapehene composite that has 180 times the tensile strength of nickel (4 gigapascals). This is still some way off graphene’s tensile strength of 130 GPa — which is about 200 times stronger than steel (600 MPa) — but it’s still very, very strong. At 1.5 GPa, copper-graphene is about 50% stronger than titanium, or about three times as strong as structural aluminium alloys.

This was covered in August 2013 by Nextbigfuture. Apologies for the repetition.

Schematic of metal–graphene multilayer system synthesis. In separate research announced in May, 2013, Columbia Engineering researchers demonstrated that graphene, even if stitched together from many small crystalline grains, is almost as strong as graphene in its perfect crystalline form. This work resolves a contradiction between theoretical simulations, which predicted that grain boundaries can be strong, and earlier experiments, which indicated that they were much weaker than the perfect lattice. Scientists can grow sheets of graphene as large as a television screen by using chemical vapor deposition (CVD), in which single layers of graphene are grown on copper substrates in a high-temperature furnace. One of the first applications of graphene may be as a conducting layer in flexible displays. The graphene has a strength of 95 gigapascals. It has 90% of the strength of perfect molecular graphene and is stronger than molecular carbon nanotubes. The copper-graphene multilayer material with an interplanar distance of 70nm exhibited 500 times greater (1.5GPa) strength than pure copper and nickel-graphene multilayer material with an interplanar distance of 100nm showed 180 times greater (4.0GPa) strength than pure nickel. It was found that there is a clear relationship between the interplanar distance and the strength of the multilayer material. A smaller interplanar distance made dislocation movement more difficult and therefore increased the strength of the material. Professor Han, who led the research effort, commented "the result is astounding as 0.00004% in weight of graphene increased the strength of the materials by hundreds of times" and that "improvements based on this success, especially enabling mass production with roll-to -roll process or metal sintering process, in the production of automobile and spacecraft lightweight, ultra-high strength parts may become possible. "In addition Professor Han mentioned that" the new material can be applied to coating material for nuclear reactor construction or other structural materials requiring high reliability. Nature Communications - Strengthening effect of single-atomic-layer graphene in metal–graphene nanolayered composites The US Army Armaments Research, Development and Engineering Center developed a graphene-metal nanomaterial but failed to drastically improve the strength of the material. To maximize the increase in strength imparted by the addition of graphene, the KAIST research team created a layered structure of metal and graphene. Using CVD (Chemical Vapor Deposition) the team grew a single layer of graphene on a metal deposited substrate then deposited another metal layer and repeated the process to produce a metal-graphene multilayer composite material that, achieving a world first in doing so, utilized single layer of graphene. Micro-compression tests within Transmission Electronic Microscope and Molecular Dynamics simulation effectively showed the strength enhancing effect and the dislocation movement on an atomic level. The mechanical characteristics of the graphene layer within the metal-graphene composite material successfully blocked the dislocations and cracks from external damage from traveling inwards. Therefore the composite material displayed strength beyond conventional metal-metal multilayer materials. ABSTRACT - Graphene is a single-atomic-layer material with excellent mechanical properties and has the potential to enhance the strength of composites. Its two-dimensional geometry, high intrinsic strength and modulus can effectively constrain dislocation motion, resulting in the significant strengthening of metals. Here we demonstrate a new material design in the form of a nanolayered composite consisting of alternating layers of metal (copper or nickel) and monolayer graphene that has ultra-high strengths of 1.5 and 4.0 GPa for copper–graphene with 70-nm repeat layer spacing and nickel–graphene with 100-nm repeat layer spacing, respectively. The ultra-high strengths of these metal–graphene nanolayered structures indicate the effectiveness of graphene in blocking dislocation propagation across the metal–graphene interface. Ex situ and in situ transmission electron microscopy compression tests and molecular dynamics simulations confirm a build-up of dislocations at the graphene interface. 6 pages of supplemental material. If you liked this article, please give it a quick review on ycombinator or StumbleUpon. Thanks