The researchers report in Nano Letters that by combining inorganic semiconductor nanocrystals with organic molecules, they have succeeded in"upconverting"photons in the visible and near-infrared regions of the solar spectrum."
In their experiments, Bardeen and Tang worked with cadmium selenide and lead selenide semiconductor nanocrystals.
"The key to this research is the hybrid composite material--combining inorganic semiconductor nanoparticles with organic compounds.
"Besides solar energy, the ability to upconvert two low energy photons into one high energy photon has potential applications in biological imaging, data storage and organic light-emitting diodes.
and industries, including laser, solar cells, production of transistors and nanomedicine. The colloid form of these particles have very interesting properties and characteristics,
This energy gap, in addition to other parameters such as density difference in electrical charges and type and density of surface atoms,
electronics and photonics after passing the required tests and obtaining mass-production of these nanoparticles.
In this context, recently, researchers at the Department of Environmental and Life sciences at Toyohashi Tech have developed a practical magnetic metallic contaminant detector using three high-Tc RF superconducting quantum interference devices
The detection technique is based on recording the remnant magnetic field of a contaminant using SQUID sensors.
SQUID is a high-sensitivity magnetic sensor based on the superconductivity phenomenon. In the process, a strong magnetic field is applied to food to magnetize the metal fragments inside,
can be detected by sensing their magnetic fields using SQUID sensors. This method is advantageous in the sense that it is both safe
the sensor is placed inside a square metallic box designed such that food can be tested as it passes through this box.
Thus, magnetic fields around the sensor are concentrated in the walls of this box.""In experiments, the developed system was able to clearly detect a steel ball with a diameter as small as 0. 3 mm.
#Meet the high-performance single-molecule diode: Major milestone in molecular electronics scored by Berkeley Lab and Columbia University team"Using a single symmetric molecule, an ionic solution and two gold electrodes of dramatically different exposed surface areas,
we were able to create a diode that resulted in a rectification ratio, the ratio of forward to reverse current at fixed voltage, in excess of 200,
which is a record for single-molecule devices, "says Jeff Neaton, Director of the Molecular Foundry, a senior faculty scientist with Berkeley Lab's Materials sciences Division and the Department of physics at the University of California Berkeley,
"The asymmetry necessary for diode behavior originates with the different exposed electrode areas and the ionic solution,
"This leads to different electrostatic environments surrounding the two electrodes and superlative single-molecule device behavior."
"With"smaller and faster"as the driving mantra of the electronics industry, single-molecule devices represent the ultimate limit in electronic miniaturization.
Since then, development of functional single-molecule electronic devices has been a major pursuit with diodes-one of the most widely used electronic components-being at the top of the list.
A typical diode consists of a silicon p-n junction between a pair of electrodes (anode and cathode) that serves as the"valve"of an electrical circuit,
Scientists have fashioned previously single-molecule diodes either through the chemical synthesis of special asymmetric molecules that are analogous to a p-n junction;
or through the use of symmetric molecules with different metals as the two electrodes. However, the resulting asymmetric junctions yielded low rectification ratios,
"The efficiency of the tunneling process depends intimately on the degree of alignment of the molecule's discrete energy levels with the electrode's continuous spectrum.
and Zhenfei Liu to understand the diode behavior quantitatively.""In collaboration with Columbia University's Latha Venkataraman and Luis Campos and their respective research groups, Neaton and Liu fabricated a high-performing rectifier from junctions made of symmetric molecules with molecular resonance
in nearly perfect alignment with the Fermi electron energy levels of the gold electrodes. Symmetry was broken by a substantial difference in the size of the area on each gold electrode that was exposed to the ionic solution.
Owing to the asymmetric electrode area, the ionic solution, and the junction energy level alignment, a positive voltage increases current substantially;
a negative voltage suppresses it equally significantly.""The ionic solution, combined with the asymmetry in electrode areas, allows us to control the junction's electrostatic environment simply by changing the bias polarity,
"Neaton says.""In addition to breaking symmetry, double layers formed by ionic solution also generate dipole differences at the two electrodes,
which is the underlying reason behind the asymmetric shift of molecular resonance. The Columbia group's experiments showed that with the same molecule and electrode setup,
a nonionic solution yields no rectification at all.""The Berkeley Lab-Columbia University team believes their new approach to a single-molecule diode provides a general route for tuning nonlinear nanoscale-device phenomena that could be applied to systems beyond single-molecule junctions
and two-terminal devices.""We expect the understanding gained from this work to be applicable to ionic liquid gating in other contexts,
The paper is titled"Single-molecule diodes with high rectification ratios through environmental control.""Other co-authors are Brian Capozzi, Jianlong Xia, Olgun Adak, Emma Dell, Zhen-Fei Liu and Jeffrey Taylor r
#Sol-gel capacitor dielectric offers record-high energy storage If the material can be scaled up from laboratory samples,
Capacitors often complement batteries in these applications because they can provide large amounts of current quickly.
Perry and colleagues in Georgia Tech's Center for Organic photonics and Electronics (COPE) had been working on other capacitor materials to meet these demands
so the group decided to pursue these materials for the new capacitor applications. Using an aluminized mylar film coated with the hybrid sol-gel capacitor material,
they showed that the capacitor could be rolled and rerolled several times while maintaining high energy density, demonstrating its flexibility.
But they were still seeing high current leakage. To address that, they deposited a nanoscale self-assembled monolayer of n-octylphosphonic acid on top of the hybrid sol-gel.
though it doesn't match the lithium ion battery formats commonly used in electronic devices and vehicles.""This is the first time I've seen a capacitor beat a battery on energy density,
"said Perry.""The combination of high energy density and high power density is uncommon in the capacitor world."
"Researchers in Perry's lab have been making arrays of small sol-gel capacitors in the lab to gather information about the material's performance.
The devices are made on small substrates about an inch square.""What we see when we apply an electric field is that the polarization response
"This is what you want to see in a capacitor dielectric material.""The next step will be to scale up the materials to see if the attractive properties transfer to larger devices.
"This work emphasizes the importance of controlling the electrode-dielectric interface to maximize the performance of dielectric materials for energy storage application
By shrinking them down in size, researchers will be able to cram millions of these devices on a single chip.
In a paper published in Scientific Reports("Single-cell Migration Chip for Chemotaxis-based Microfluidic Selection of Heterogeneous Cell Populations),
#Scientists print low cost radio frequency antenna with graphene ink (Nanowerk News) Scientists have moved graphene--the incredibly strong and conductive single-atom-thick sheet of carbon--a significant step along the path
Researchers from the University of Manchester, together with BGT Materials Limited, a graphene manufacturer in the United kingdom, have printed a radio frequency antenna using compressed graphene ink.
The antenna performed well enough to make it practical for use in radio-frequency identification (RFID) tags and wireless sensors,
the antenna is flexible, environmentally friendly and could be cheaply mass-produced. The researchers present their results in the journal Applied Physics Letters,
"These scanning electron microscope images show the graphene ink after it was deposited and dried (a) and after it was compressed (b). Compression makes the graphene nanoflakes more dense,
said Zhirun Hu, a researcher in the School of Electrical and Electronic engineering at the University of Manchester."
which can be used to print circuits and other electronic components. Graphene ink is generally low cost and mechanically flexible
Paving the Way to Antennas, Wireless Sensors, and More The researchers tested their compressed graphene laminate by printing a graphene antenna onto a piece of paper.
The antenna measured approximately 14 centimeters long, and 3. 5 millimeter across and radiated radio frequency power effectively,
said Xianjun Huang, who is the first author of the paper and a Phd candidate in the Microwave and Communcations Group in the School of Electrical and Electronic engineering.
Printing electronics onto cheap, flexible materials like paper and plastic could mean that wireless technology,
like RFID tags that currently transmit identifying info on everything from cattle to car parts,
as well as sensors and wearable electronics s
#Printing 3-D graphene structures for tissue engineering Ever since single-layer graphene burst onto the science scene in 2004,
and ultra-strong and lightweight structure, graphene has potential for many applications in electronics, energy, the environment,
An expert in biomaterials, Shah said 3-D printed graphene scaffolds could play a role in tissue engineering and regenerative medicine as well as in electronic devices.
so it could be used for biodegradable sensors and medical implants. Shah said the biocompatible elastomer
Many researchers see improved interconnection of optical and electronic components as a path to more efficient computation and imaging systems.
to create tiny optical waveguides, about 20 nanometers in size the same size range as the smallest features that can now be produced in microchips.
This could lead to chips that combine optical and electronic components in a single device, with far lower losses than when such devices are made separately and then interconnected,
they say. Co-author Tony Low, a researcher at IBM and the University of Minnesota, says,
The work is retty criticalfor providing the understanding needed to develop optoelectronic or photonic devices based on graphene and hbn,
#Toward'green'paper-thin, flexible electronics (Nanowerk News) The rapid evolution of gadgets has brought us an impressive array of smart products from phones to tablets,
A Transparent and Photoluminescent Foldable Nanocellulose/Quantum dot Paper")a new step toward bendable electronics. They have developed the first light-emitting, transparent and flexible paper out of environmentally friendly materials via a simple, suction-filtration method.
roll up electronics. American Chemical Society) Technology experts have predicted long the coming age of flexible electronics,
and researchers have been working on multiple fronts to reach that goal. But many of the advances rely on petroleum-based plastics and toxic materials.
wearable sensors that can do the same thing. Their technology, reported in the journal ACS Nano("Stretchable, Transparent, Ultrasensitive,
and Patchable Strain Sensor for Humanmachine Interfaces Comprising a Nanohybrid of Carbon nanotubes and Conductive Elastomers"),could help robot developers make their machines more human.
Most current efforts toward this goal analyze a person's feelings using visual sensors that can tell a smile from a frown, for example.
low-cost sensors to detect facial movements, including slight changes in gaze. The researchers created a stretchable and transparent sensor by layering a carbon nanotube film on two different kinds of electrically conductive elastomers.
They found it could tell whether subjects were laughing or crying and where they were looking.
the sensors could be used to monitor heartbeats, breathing, dysphagia (difficulty swallowing) and other health-related cues s
and well-controlled fabrication of nanotubular electrodes to accommodate ion motion in and out and close contact between the thin nested tubes to ensure fast transport for both ions and electrons.
using atomic layer deposition to carefully control thickness and length of multilayer concentric nanotubes as electrodes at each end.
what happens at the surface of a double-layer capacitor. Science Impact These nanobatteries delivered their stored energy efficiently at high power (fast charge
they can be used to create a new generation of sensors and actuators with vanishingly small heat signatures,
the researchers pass a suspension of B cells and target antigen through tiny, parallel channels etched on a chip.
society's thirst for powerful sensors is growing. Given that, few sensing techniques can match the buzz created by surface-enhanced Raman spectroscopy (SERS.
and semiconductors, are known to be important to this process and others such as photosynthesis and optical communications.
This discovery sheds light on the primary excitonic response of solids which could allow quantum control of electrons in metals, semiconductors,
It also potentially allows for the generation of intense femotosecond electron pulses that could increase resolution for time-resolved electron microscopes that follow the motion of individual atoms
"Self-assembled three-dimensional and compressible interdigitated thin-film supercapacitors and batteries")."This is a closeup of the soft battery,
enabling us to fit more electronics in a smaller space.""A 3d structure enables storage of significantly more power in less space than is possible with conventional batteries,
"Three-dimensional, porous materials have been regarded as an obstacle to building electrodes. But we have proven that this is not a problem.
While flexible and stretchable electronics already exist, the insensitivity to shock and impact are somewhat new."
and his work on aerogels is in the basis for the invention of soft electronics. Another partner is leading battery researcher, Professor Yi Cui from Stanford university y
and logic gates"),is the first step in the use of programmable cells for medical diagnosis. Bacteria have a bad reputation,
Jérôme Bonnet's team in Montpellier's Centre for Structural Biochemistry (CBS) had the idea of using concepts from synthetic biology derived from electronics to construct genetic systems making it possible to"programme"living cells like a computer.
the cornerstone of genetic programming The transistor is the central component of modern electronic systems. It acts both as a switch and as a signal amplifier.
In informatics, by combining several transistors, it is possible to construct"logic gates, "i e. systems that respond to different signal combinations according to a predetermined logic.
For example, a dual input"AND"logic gate will produce a signal only if two input signals are present.
All calculations completed by the electronic instruments we use every day, such as smartphones, rely on the use of transistors and logic gates.
During his postdoctoral fellowship at Stanford university in the United states Jérôme Bonnet invented a genetic transistor, the transcriptor.
The insertion of one or more transcriptors into bacteria transforms them into microscopic calculators. The electrical signals used in electronics are replaced by molecular signals that control gene expression.
It is thus now possible to implant simple genetic"programmes"into living cells in response to different combinations of molecules.
In this new work, the teams led by Jérôme Bonnet (CBS, Inserm U1054, CNRS UMR5048, Montpellier University), Franck Molina (Sysdiag, CNRS FRE 3690),
As a proof of concept, the authors connected the genetic transistor to a bacterial system that responds to glucose,
Low-cost pollution detectors to tackle air quality (w/video) Rush hour can be maddening. Roads congested with traffic,
With this in mind, Jonesteam, together with industrial partners and other universities, has been developing low-cost pollution detectors that are small enough to fit in your pocket,
stable enough to be installed as long-term static detectors around a city, and sensitive enough to detect small changes in air quality on a street-by-street basis. Their findings are now informing research projects aimed at improving air quality in major cities across Europe and North america.
The detectors are based on electrochemical sensors developed by project partner Alphasense for industrial safety where detection of toxic gases is needed at the parts-per-million level.
I had the confidence to believe that we could push our sensors to lower concentration levels,
and yet keep sensor costs low, says Dr John Saffell, Technical Director at Alphasense. The electrochemical devices the team developed can measure a wide range of pollutants,
They also discovered that sensor performance can create new opportunities. Jones and colleagues had to develop new smart software methods capable of separating local pollution events from background signals (pollution transported from long range)
and then to calibrate sensors across networks. Plus, they needed to move from being able to process the data after it has been collected to doing so in real-time.
For instance, sensors can be used to ask whether pollution along bus routes is improved by upgrading the exhaust processing on a bus fleet;
AQMESH uses Alphasense sensors to sample every 10 seconds, and data processing is carried out in real-time using cloud computing software similar to that developed by the Cambridge team. hen the project started in 2006 there were lone voices calling for a different approach to air quality monitoring,
and Alphasense helped us to understand the sensor full potential, and now we have a product that can be placed exactly where it needed
aims to deploy large numbers of air quality sensors across the whole of Greater london. Alphasense is providing the sensors and supporting the engineering;
and Cambridge is helping with data interpretation in a project whose ethos is ou can manage
they combine the physical solid-state properties of e g. ceramics or semiconductors with classic polymer-processing technology.
Titanium dioxide, barium titanate, indium-tin oxide or zirconium dioxide, for instance, are used as nanoparticles. In addition to the chemical intrinsic composition of the nanoparticles and their SMSM surface treatment, the properties that are attainable for the desired coatings also vary with the size and dispersal mode of the nanoparticles.
"Scanning electron microscope image of an individual nano-spiral. Image: Haglund Lab/Vanderbilt) They are certainly smaller than any of the spirals weve found reported in the scientific literature,
One potential solution is to leverage surface electromyography using small electrical sensors in a cuff worn around the patient's forearm.
The electromyography sensors-which could be used to directly control the glove work by detecting the residual muscle signals fired by motor neurons
#A universal transition Understanding what causes materials to change from electrical insulators to metallic conductors is relevant not only to the development of practical electronic devices,
a solid material with spin-transition solution-like behaviour Spintronics is called a discipline to change the way we store
Metal complexes showing spin-transition (i e. reversible interconversion between different isomers) are among the best candidates for the preparation of molecular memories and spintronic devices.
#Next-generation illumination using silicon quantum dot-based white-blue LED (Nanowerk News) A silicon quantum dot (QD)- based hybrid inorganic/organic light-emitting diode (LED) that exhibits white-blue electroluminescence
and their collaborators (Applied Physics Letters,"White-blue electroluminescence from a Si quantum dot hybrid light-emitting diode").
"Professor Ken-ichi Saitow, Natural science Center for Basic Research and development, Hiroshima University and Graduate student Yunzi Xin, Graduate school of Science, Hiroshima University, have fabricated an Si QD hybrid LED.
A hybrid LED is expected to be a next-generation illumination device for producing flexible lighting and display,
and this is achieved for the Si QD-based white-blue LED. The Si QD hybrid LED was developed using a simple method;
almost all processes were based solution and conducted at ambient temperature and pressure. Conductive polymer solutions and a colloidal Si QD solution were deposited on the glass substrate.
The current and optical power densities of the LED are, respectively, 280 and 350 times greater than those reported previously for such a device at the same voltage (6 V). In addition,
the active area of the LED is 4 mm2, which is 40 times larger than that of a typical commercial LED;
the thickness of the LED is 0. 5 mm. Professor Saitow stated,"QD LED has attracted significant attention as a next-generation LED.
Although several breakthroughs will be required for achieving implementation, a QD-based hybrid LED allows us to give so fruitful feature that we cannot imagine."
"Regarding quantum dots: Semiconductor QDS can produce full-color luminescence through tuning of the particle size.
QDS have attracted significant attention as potential components of next-generation solid-state light sources, including LEDS s
#Researchers design the most precise quantum thermometer to date (Nanowerk News) Physics at the UAB have found the formula to construct a quantum thermometer with enough precision to detect minute fluctuations in temperature in regions as small as the inside of a cell.
The research appears today in the journal Physical Review Letters("Individual quantum probes for optimal thermometry".
#Injectable nanoelectronics for treatment of neurodegenerative diseases It's a notion that might be pulled from the pages of science-fiction novel-electronic devices that can be injected directly into the brain,
Once connected to electronic devices, the scaffolds can be used to monitor neural activity, stimulate tissues and even promote regenerations of neurons.
The study is described in a June 8 paper in Nature Nanotechnology("Syringe-injectable electronics"."Contributing to the work were Jia Liu, Tian-Ming Fu, Zengguang Cheng, Guosong Hong, Tao Zhou, Lihua Jin, Madhavi Duvvuri, Zhe Jiang, Peter
but no one has addressed this issue-the electronics/cellular interface-at the level at which biology works."
When releasing the electronics scaffold completely from the fabrication substrate, we noticed that it was almost invisible and very flexible like a polymer
would it be possible to deliver the mesh electronics by syringe needle injection, a process common to delivery of many species in biology and medicine-you could go to the doctor
'"Though not the first attempts at implanting electronics into the brain-deep brain stimulation has been used to treat a variety of disorders for decades-the nano-fabricated scaffolds operate on a completely different scale.
But with our injectable electronics, it's as if it's not there at all. They are one million times more flexible than any state-of-the-art flexible electronics
and have subcellular feature sizes. They're what I call"neuro-philic"-they actually like to interact with neurons.."
The process is used similar to that to etch microchips, and begins with a dissolvable layer deposited on a substrate.
After injection, the input/output of the mesh can be connected to standard measurement electronics so that the integrated devices can be addressed
and used to stimulate or record neural activity.""These type of things have never been done before, from both a fundamental neuroscience and medical perspective,
and other tissues react to the injectable electronics over longer periods. Harvard's Office of Technology Development has filed for a provisional patent on the technology
#Researchers build world's first fully functioning single crystal waveguide in glass Researchers from Lehigh University,
and demonstrating what they call the"world's first fully functioning single crystal waveguide in glass."
"In an article published in Scientific Reports("Direct laser-writing of ferroelectric single-crystal waveguide architectures in glass for 3d integrated optics),
The group says its achievement will boost ongoing efforts to develop photonic integrated circuits (PICS) that are smaller, cheaper, more energy-efficient and more reliable than current networks that use discrete optoelectronic components--waveguides, splitters, modulators, filters
, amplifiers--to transport optical signals.""A major trend in optics,"the researchers write, "has been a drive toward...
in much the same way that integration of electronics has driven the impressive advances of modern computer systems."
"Amorphous waveguides fundamentally lack second-order optical nonlinearity due to their isotropically disordered atomic structure, "the researchers write,
According to Dhinojwala, One could think about applications as sensors, photo-protectors, and even perhaps an approach to create a wide range of colors without using any pigments,
Dmitry Fedyanin and Yury Stebunov, have developed an ultracompact highly sensitive nanomechanical sensor for analyzing the chemical composition of substances and detecting biological objects,
The sensor will enable doctors to identify tumor markers, whose presence in the body signals the emergence and growth of cancerous tumors.
according to its developers, the sensor can track changes of just a few kilodaltons in the mass of a cantilever in real time.
So the new optical sensor will allow for diagnosing diseases long before they can be detected by any other method,
The device, described in an article published in the journal Scientific Reports("All-nanophotonic NEMS biosensor on a chip"
is an optical or, more precisely, optomechanical chip.""We've been following the progress made in the development of micro
So our goal was not only to achieve the high sensitivity of the sensor and make it compact,
but also make it scalabile and compatibile with standard microelectronics technologies, "the researchers said. Unlike similar devices, the new sensor has no complex junctions
and can be produced through a standard CMOS process technology used in microelectronics. The sensor doesn't have a single circuit
and its design is very simple. It consists of two parts: a photonic (or plasmonic) nanowave guide to control the optical signal,
and a cantilever hanging over the waveguide. A cantilever, or beam, is a long and thin strip of microscopic dimensions (5 micrometers long,
1 micrometer wide and 90 nanometers thick), connected tightly to a chip. To get an idea how it works,
imagine you press one end of a ruler tightly to the edge of a table
There are two optical signals going through the waveguide during oscillations: the first one sets the cantilever in motion,
Without the nanoscale waveguide and the cantilever, the chip simply wouldn't work. Abig cantilever cannot be made to oscillate by freely propagating light,
Cantilever oscillations make it possible to determine the chemical composition of the environment in which the chip is placed.
and the electromagnetic wave passing through the waveguide will be dispersed by the cantilever differently, which can be seen in the changes of the intensity of the readout signal.
Calculations done by the researchers showed that the new sensor will combine high sensitivity with a comparative ease of production and miniature dimensions
allowing it to be used in all portable devices, such as smartphones, wearable electronics, etc. One chip, several millimeters in size, will be able to accommodate several thousand such sensors,
configured to detect different particles or molecules. The price, thanks to the simplicity of the design, will most likely depend on the number of sensors,
being much more affordable than its competitors s
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