The most familiar photovoltaic (PV) designs use rigid layers of silicon crystal, but recently inexpensive organic semiconductor materials have also been used successfully. At this time, organic PV devices are hindered by low efficiency, in part because quantifying their electrical properties is a challenge. Researchers have now developed a method that allows the prediction of the current density-voltage curve of a photovoltaic device.
Lighter, more flexible and cheaper than conventional solar-cell materials, carbon nanotubes (CNTs) have long shown promise for photovoltaics. But research stalled when CNTs proved to be inefficient, converting far less sunlight into power than other methods. Now a research team has created a new type of CNT solar cell that is twice as efficient as its predecessors.
When metallic lithium forms and deposits during the charging process in a lithium-ion battery, it can lead to a reduced battery lifespan and even short circuits. Using neutron beams, scientists have now peered into the inner workings of a functioning battery without destroying it. In the process, they have resolved this so-called lithium plating mystery.
As a semiconductor material, germanium is superior to silicon. But it is more expensive to process for widespread use in batteries, solar cells, transistors and other applications. Researchers in Missouri have now developed what they call “a simple, one-step method” to grow nanowires of germanium from an aqueous solution. Their process could make it more feasible to use germanium in lithium-ion batteries.
Physicists studying the effects of embedding magnetic spins onto the surface of a superconductor recently report that the spins can interact differently than previously thought. This hybrid platform could be useful for quantum simulations of complex spin systems, having the special feature that the interactions may be controllable, something quite unusual for most condensed matter systems.
A team of researchers in the U.S. and China have developed a new sensor that can detect and count nanoparticles, at sizes as small as 10 nm, one at a time. The researchers say the sensor, which is a Raman microlaser sensor in a silicon dioxide chip that does not need rare-earth ions to achieve high resolution, could potentially detect much smaller particles, viruses and small molecules.
Scientists at Oak Ridge National Laboratory have discovered they can control chemical reactions in a new way by creating different shapes of cerium oxide, a rare-earth-based catalyst. Their finding holds potential for refining fuels, decreasing vehicle emissions, producing commodity chemicals and advancing fuel cells and chemical sensors.
An international group of scientists posit that a comet collision with Earth played a major role in the extinction of most of North America’s megafauna close to 13,000 years ago. In a new study, they have focused on the character and distribution of nanodiamonds, which are produced during such an extraterrestrial collision. The researchers found an abundance of these tiny diamonds distributed over 50 million km2 in the Northern Hemisphere.
Researchers have discussed the merits of surface-stress influence on mechanical properties for decades. Now, a new research platform, called nanomechanical Raman spectroscopy and developed at Purdue Univ., uses a laser to measure the "nanomechanical" properties of tiny structures undergoing stress and heating.
Recycled tires could see new life in lithium-ion batteries that provide power to plug-in electric vehicles and store energy produced by wind and solar, say researchers at Oak Ridge National Laboratory. By modifying the microstructural characteristics of carbon black, a substance recovered from discarded tires, a team of researchers is developing a better anode for lithium-ion batteries.
Recent experiments have confirmed that a technique developed several years ago at NIST can enable optical microscopes to measure the 3-D shape of objects at nanometer-scale resolution—far below the normal resolution limit for optical microscopy (about 250 nm for green light). The results could make the technique a useful quality control tool in the manufacture of nanoscale devices such as next-generation microchips.
The field of astrophysics has a stubborn problem and it’s called lithium. The quantities of lithium predicted to have resulted from the Big Bang are not actually present in stars. But the calculations are correct, a fact which has now been confirmed for the first time in experiments conducted at the underground laboratory in the Gran Sasso mountain in Italy.
Sensors made with copper could be cheap, light, flexible and highly conductive. Making such concepts affordable enough for general use remains a challenge but a new way of working with copper nanowires and a PVA “nano glue” could be a game-changer. Engineers in Australia have found a way of making flexible copper conductors cost-effective enough for commercial applications.
Univ. of Washington researchers have developed what they believe is the thinnest-possible semiconductor, a new class of nanoscale materials made in sheets only three atoms thick. They have demonstrated that two of these single-layer semiconductor materials can be connected in an atomically seamless fashion known as a heterojunction. This result could be the basis for next-generation flexible and transparent computing.
Scientists in The Netherlands have demonstrated that they can detect extremely small changes in position and forces on very small drums of graphene. Graphene drums have great potential to be used as sensors in devices such as mobile phones. Using their unique mechanical properties, these drums could also act as memory chips in a quantum computer.
A new argument has just been added to the growing case for graphene being bumped off its pedestal as the next big thing in the high-tech world by the 2-D semiconductors known as MX2 materials. An international collaboration of researchers led by Lawrence Berkeley National Laboratory has reported the first experimental observation of ultrafast charge transfer in photo-excited MX2 materials.
For tiny fractions of a second, when illuminated by a laser pulse, quartz glass can take on metallic properties. The phenomenon, recently revealed by large-scale computer simulations, frees electrons, allowing quartz to become opaque and conduct electricity. The effect could be used to build logical switches which are much faster than today’s microelectronics.
Polymers come with a range of properties dictated by their chemical composition and geometrical arrangement. Yasuyuki Tezuka and his team at Tokyo Institute of Technology have now applied an approach to synthesize a new type of multicyclic polymer geometry. While mathematicians are interested because these structures have not been realized before, the geometry studies also provide insights for chemists.
Univ. of Illinois engineers are bringing a touch of color to glucose monitoring. The researchers developed a new continuous glucose monitoring material that changes color as glucose levels fluctuate, and the wavelength shift is so precise that doctors and patients may be able to use it for automatic insulin dosing—something now possible using current point measurements like test strips.
A team of scientists from Germany, Canada, and the United States has now developed a promising new measurement method that works without destroying anything yet offers nanoscale resolution. The method, an enhancement of resonant x-ray reflectometry identifies the chemical elements involved and is able to determine both the magnetic order and the electron distribution.
Rice Univ. researchers have created a CMOS-compatible, biomimetic color photodetector that directly responds to red, green and blue light in much the same way the human eye does. The new device uses an aluminum grating that can be added to silicon photodetectors with the silicon microchip industry’s mainstay technology, “complementary metal-oxide semiconductor,” or CMOS.
The first direct observations of how facets form and develop on platinum nanocubes point the way towards more sophisticated and effective nanocrystal design and reveal that a nearly 150 year-old scientific law describing crystal growth breaks down at the nanoscale.
New measurements of atomic-scale magnetic behavior in iron-based superconductors by researchers at Oak Ridge National Laboratory and Vanderbilt Univ. are challenging conventional wisdom about superconductivity and magnetism. The study provides experimental evidence that local magnetic fluctuations can influence the performance of iron-based superconductors, which transmit electric current without resistance at relatively high temperatures.
Research published in ACS Nano identifies a new type of sensor that could monitor body movement and advance the future of global health care. Although body motion sensors already exist in different forms, they have not been widely used due to their complexity and cost of production.
Materials like solid gels and porous foams are used for padding and cushioning, but each has its own advantages and limitations. To overcome limitations, a team from Lawrence Livermore National Laboratory has found a way to design and fabricate, at the microscale, new cushioning materials with a broad range of programmable properties and behaviors that exceed the limitations of the material's composition through 3-D printing.