Researchers design and patent graphene biosensors. @nanotech1

Researchers design and patent graphene biosensors
(Nanowerk News) The Moscow Institute of Physics and Technology (MIPT) is patenting biosensor chips based on graphene, graphene oxide and carbon nanotubes that will improve the analysis of biochemical reactions and accelerate the development of novel drugs. @nanotech1
The US Patent Office has recently published the patent application (US 2015/0301039), which was filed by the MIPT in May this year and is titled Biological Sensor and a Method of the Production of Biological Sensor. In Russia, this development is already protected by the patent No. 2527699 with a priority date of February 20, 2013. The key feature of the sensor is the use of a linking layer for biomolecule immobilization comprising a thin film of graphene or graphene oxide.

http://www.nanowerk.com/nanotechnology-news/newsid=41854.php

Nanopores could take the salt out of seawater

Read more: Nanopores could take the salt out of seawater. @nanotech1

Nanopores could take the salt out of seawater
(Nanowerk News) University of Illinois engineers have found an energy-efficient material for removing salt from seawater that could provide a rebuttal to poet Samuel Taylor Coleridge's lament, "Water, water, every where, nor any drop to drink."@nanotech1
The material, a nanometer-thick sheet of molybdenum disulfide (MoS2) riddled with tiny holes called nanopores, is specially designed to let high volumes of water through but keep salt and other contaminates out, a process called desalination. In a study published in the journal Nature Communications ("Water desalination with a single-layer MoS2 nanopore"), the Illinois team modeled various thin-film membranes and found that MoS2 showed the greatest efficiency, filtering through up to 70 percent more water than graphene membranes. http://www.nanowerk.com/nanotechnology-news/newsid=41830.php

New measurements in 2-D materials hold great promise for nanotechnology applications
(Nanowerk News) Scientists working at the new CUNY Advanced Science Research Center have helped to develop measurements in two-dimensional materials that hold great promise for nanotechnology applications. This research is considered “an important technological and scientific advancement,” according to the journal, Nature Materials ("Elastic coupling between layers in two-dimensional materials")
“Researchers seek to understand two-dimensional (2D) materials because of their potential applications in photonics, nanoelectronics, nanomechanics, and thermoelectrics” says study leader Dr. Elisa Riedo, professor of physics at the City College-based CUNY Advanced Science Research Center.
These materials, such as epitaxial graphene and MoS2, are films made of a few layers, with each layer only one atom thick. The films are characterized by strong in-plane bonds and weak interactions between the layers.
Sub-angstrom-resolution indentations were used to measure the forces between the atomic layers. Now while the in-plane elasticity of these materials has been widely studied in the past, little was known about the films’ elastic modulus perpendicular to the planes. That is because these types of measurements require ultra-small indentations.
Riedo and her collaborators, including Dr. Yang Gao of CUNY ASRC, were then able to measure and control indentation depths smaller than the films’ interlayer distance. By combining experiments with the density functional theory calculations of Dr. Angelo Bongiorno, a co-principal investigator at the College of Staten Island, the team was able to tune the interlayer elasticity by water molecule intercalation.
The research team also included members from France, and Italy. Support for the study, which appears in “Nature Materials,” was provided by the Office of Basic Energy Sciences of the U.S. Department of Energy.
@nanotech1

Fool’s Gold Quantum Dots Significantly Enhance the Charging Speed of Batteries. @nanotech1

Fool’s Gold Quantum Dots Significantly Enhance the Charging Speed of Batteries

It has shown that the addition of fools gold quantum dots to lithium batteries facilitates ultrafast charging that works over multiple charge cycles. Previous attempts to achieve this gave batteries that only performed well over one or two cycles.

@nanotech1
THe addition of quantum dots to a smartphone battery have been shown to enable it to charge within 30 seconds. However, until now this behaviour has only been sustainable for a small number of recharge cycles.

In this study, the team found that this problem could be addressed by using iron pyrite, or fool’s gold, to produce the quantum dots. The fools gold batteries could charge rapidly and also last for more cycles.

Iron pyrite is extremely abundant and is obtained as a byproduct of coal production. It is very cheap, and is used in disposible lithium batteries. However, the team faced significant difficulty when they tried to produce the nanoparticles to enhance battery performance.

Researchers have demonstrated that nanoscale materials can significantly improve batteries, but there is a limit.

When the particles get very small, generally meaning below 10 nanometers (40 to 50 atoms wide), the nanoparticles begin to chemically react with the electrolytes and so can only charge and discharge a few times. So this size regime is forbidden in commercial lithium-ion batteries.

Prof. Cary Pint - Vanderbilt University

The group added millions of iron pyrite quantum dots of various sizes to commonly used lithium button batteries. The team observed that nanocrystals of approximately 4.5 nm provided the best result for enhancing the rate and cycling capabilities of the lithium batteries.

When storing energy, iron pyrite changes into a different compound consisting of lithium-sulfur and iron.

This is a different mechanism from how commercial lithium-ion batteries store charge, where lithium inserts into a material during charging and is extracted while discharging – all the while leaving the material that stores the lithium mostly unchanged

Anna Douglas - Vanderbilt University

You can think of it like vanilla cake. Storing lithium or sodium in conventional battery materials is like pushing chocolate chips into the cake and then pulling the intact chips back out.

With the interesting materials we’re studying, you put chocolate chips into vanilla cake and it changes into a chocolate cake with vanilla chips.

Prof. Cary Pint - Vanderbilt University

Quantum dots must be used as during each charge and discharge cycle iron atoms need to diffuse into and out of the fools gold. As iron diffuses slowly the size of each fools gold particle must be smaller than the iron diffusion length, this is only possible if the nanoparticles are ultrasmall.

The team observed that the small dimensions of the ultra-small nanoparticles enabled iron to move to the surface when the lithium reacted with the iron pyrite’s sulfurs. However, when the particles were larger, iron was not able to move through the iron pyrite materials and this restricted the storage capability of the material.

Gaining insights into chemical storage mechanisms and their dependency on nanoscale dimensions is important for enhancing the performance of batteries so they can be used in electric vehicles.

The batteries of tomorrow that can charge in seconds and discharge in days will not just use nanotechnology, they will benefit from the development of new tools that will allow us to design nanostructures that can stand up to tens of thousands of cycles and possess energy storage capacities rivaling that of gasoline.

Our research is a major step in this direction.

Prof. Cary Pint - Vanderbilt University

The study paper has been published in the journal, ACS Nano.

NASA Develop Spherical Occulter using Super-Black Carbon-Nanotube Coating to Study the Sun’s Corona. @nanotech1

NASA Develop Spherical Occulter using Super-Black Carbon-Nanotube Coating to Study the Sun’s Corona

A team of NASA scientists are working on the development of an occulter, which blocks light from the sun, for use in a CubeSat mission to measure the sun's coronal mass ejections. To assist in the production of the occulter the researchers have been using carbon nanotubes to achieve the full absorption of light

Principal Investigator Phillip Chamberlin holds a sphere coated in super-black carbon nanotubes
@nanotech1
An occulter is a device that is used to block bright light. This device would fly in formation with a CubeSat, a miniturised satilite, containing an imaging spectrograph to study the sun’s corona, and more specifically it's coronal mass ejections.

Coronal mass ejections are gigantic bubbles which burst on the sun's surface; spewing out a stream of charged particles that move rapidly across the solar system.

These particles have the potential to damage the electronics on Earth's power grids or low-Earth-orbiting satellites by slamming into Earth’s protective magnetosphere.

The novel combination of an occulter working alonside a satellite will allow the speed and temperature of ejected electrons to be measured.

Understanding How the Corona Evolves
Scientists can gain better insights into the evolution of the corona and also the coronal mass ejections (CMEs) with the help of the gathered data.

Currently we can't predict them. We don't know the warning signs. We're like weather forecasters 50 years ago.

Phillip Chamberlin - NASA

The occulter is based on the Spectral Occulter Coronagraph CubeSat or SpOC. SpOC blocks sun light by producing an artificial total solar eclipse. As a result, the corona and the energetic events that occur as a result of it can be revealed. This mission would be carried out by NASA by introducing the CubeSat into an Earth-escape orbit, which travels beyond the orbit of the moon.

The occulter would be dropped by the instrument that carries the mother ship and adjustments would be made to its orbit via thrusters and navigation technology, so that it flies seven feet behind the device.

Snuffing Out the Noise
Coronagraphs are notorious for the high level of noise in their measurements. The light that passes or bends around the edges of an object due to diffraction interferes with the light that needs to be gathered by the instrument.

Chamberlin explained that one way of avoiding light contamination is to position the occulter disk very far from the instrument. The occulter in the SOHO mission it is 2.6 ft away from the coronagraph, and in the STEREO mission it is 4 ft away. For SpOC the occulter plate will be placed at 7 ft, which is almost double the distance for the STEREO mission.

The moon itself acts like a natural coronagraph, revealing a faint halo of coronal light, when it moves into a position between the Earth and the sun once a year at least. The spherical shape of the moon means that the diffraction of it's light is never concentrated; resulting in the faint halo that is observed during an eclipse.

The spherical shape of the titanium sphere used in SpOC enables the suppression of diffraction meaning it is more effective at minimizing noise. Chamberlin intends to further test the effectiveness of applying a coating of carbon-nanotubes onto the sphere.

The coating is extremely black as it is composed of multi-walled nanotubes, made of pure carbon, which are extremely effective at absorbing any stray light. This effectiveness is the result of the absorption of light by the carbon atoms nested in the nanotubes which prevent any reflection. @nanotech1

Onion-Like Nanoparticle Upconverts Infrared Radation into UV. @nanotech1

Onion-Like Nanoparticle Upconverts Infrared Radation into UV

An innovative onion-like nanoparticle has been developed that can efficiently convert low energy near-infrared radiation into UV light of a higher energy. The process involves the transfer of the infrared photons energy into the nanoparticle core, where they are fused together to form one, higher-energy photon.
@nanotech1
Measuring approximately 50nm in diameter, the new nanoparticle features three differently designed layers. Together, these three layers facilitate the efficient conversion of near-infrared light into higher energy UV light. These layers consist of an organic dye coating, a neodymium shell and a core of thulium and ytterbium.

The new onion-like nanoparticle could redefine light-based bioimaging,security methods and solar energy harvesting techniques.

Light-emitting nanoparticles within the human body can be stimulated by near-infrared light for use in bioimaging. High-contrast images of targeted areas of the body can be achieved.

For security applications, inks infused with nanoparticles could be integrated into currency designs. Whilst these types of ink cannot be seen with the naked eye they emit blue light when they are bombarded with a low-energy laser pulse, allowing the ink to be observed. As the production of the nanoparticles is complex this would be difficult to forge.

It opens up multiple possibilities for the future

Tymish Ohulchanskyy - University at Buffalo

By creating special layers that help transfer energy efficiently from the surface of the particle to the core, which emits blue and UV light, our design helps overcome some of the long-standing obstacles that previous technologies faced

Prof. Guanying Chen - Harbin Institute of Technology

It is difficult to convert low-energy light into higher energy light, a process known as 'upconversion'. This is because to achieve this, two or more photons have to be captured from a low-energy light source and then their energies have to be integrated to produce one higher-energy photon.

However, using the new nanoparticle this job can be easily accomplished. This is achieved because each uniquely designed layer displays the optimum behaviour for it's role..

Our particle is about 100 times more efficient at ‘upconverting’ light than similar nanoparticles created in the past, making it much more practical.

Tymish Ohulchanskyy - University at Buffalo

The organic dye coating, which forms the outermost layer, serves as an antenna for the nanoparticle. It absorbs and harvests photons from the near-infrared region and transfers it's energy into the particles core.

A neodymium-containing shell forms the second layer, which facilitates the transfer of energy from the dye to the light-emitting core of the nanoparticle.

Within the particle’s light-emitting core, thulium ions and ytterbium ions work in tandem to convert energy into UV light. Ytterbium ions transfer the energy from the neodymium shell and pass it to the thulium ions. Thulium ions display unique behaviour which allows them to simultaineously absorb the energy of three or more photons. By combing multiple low energy photons the thulium ions can produce one higher-energy UV photon.

Considering that the core itself is also capable of photon absorption, the use of both neodymium and dye layers appears to be unnecessary. However, by itself the core is not an efficient absorber and needs the dye to achieve a high-enough throughput. The dye itself is also not capable of efficient energy transfer, which is why the neodymium shell, that lies inbetween the core and the outer dye layer, is required

This concept can be explained using a staircase as an example;

When a photon is absorbed by matter, the matter becomes excited and transfers this energy to other ions or molecules. It has been shown that the most efficient transfer takes place between matter which require similar quantities of energy to be excited. However, the ytterbium ions and dye require different amounts of energies to enter their excited states. Neodymium forms the middle layer as the energy of its excited state is inbetween the energies of the excited states of the core thulium ions and the dye. Effectively, the neodymium serves as a bridge between the excited states of the outer and inner layers.

The three excited states form a 'staircase', allowing the energy to be passed through the nanoparticle to reach the thulium ions. @nanotech1

New Nanochip Manufacturing Technique with Atomic Precision Developed. @nanotech1

New Nanochip Manufacturing Technique with Atomic Precision Developed
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A structure sculpted by the researchers using their novel technique
@nanotech1
The new technique, which uses scanning transmission electron microscopy (STEM) can be used to build 3D structures with atomic precision. The technique is already showing use in understanding the quantum and electronic behavior of nanosized materials and is hoped to be used in the manufacturing of nanochips

The research, carried out at Oak Ridge National Laboratory and led by Albina Borisevich, showed how scanning electron microscopes could be used to precisely sculpt 3D nanoscale structures from complex oxides. Conventionally scanning transmission electron microscopes (STEMs) are only used to observe nanoscale structures and not to create them.

The use of a STEM allows structures to be constructed with atomic scale precision, meaning the technique could be used to accurately produce microchips. The structures display epitaxial growth, meaning they grow with a perfectly crystalline alignment. http://www.azonano.com/news.aspx?newsID=34140

New On-Chip Material that Transmits Light at Infinite Speeds Developed. @nanotech1

New On-Chip Material that Transmits Light at Infinite Speeds Developed
@nanotech1
Signal transmission using electrons is expected to quickly become a thing of the past. Photonic devices, which use light to rapidly transmit large volumes of information are expected to enhance, and replace, the electronic devices that we use on a daily basis. However, researchers still need to determine how to effectively manipulate light at the nanoscale before photonic devices can be integrated into computers and tellecommunications systems. @naotech1 http://www.azonano.com/news.aspx?newsID=34138