Lifeboat Foundation

As our devices get smaller and smaller, the use of molecules as the main components in electronic circuitry is becoming ever more critical. Over the past 10 years, researchers have been trying to use single molecules as conducting wires because of their small scale, distinct electronic characteristics, and high tunability. But in most molecular wires, as the length of the wire increases, the efficiency by which electrons are transmitted across the wire decreases exponentially. This limitation has made it especially challenging to build a long molecular wire—one that is much longer than a nanometer—that actually conducts electricity well.

Columbia researchers announced today that they have built a nanowire that is 2.6 nanometers long, shows an unusual increase in conductance as the wire length increases, and has quasi-metallic properties. Its excellent conductivity holds great promise for the field of molecular electronics, enabling electronic devices to become even tinier. The study is published today in Nature Chemistry.

Scientists at Tokyo Institute of Technology designed a new type of molecular wire doped with organometallic ruthenium to achieve unprecedentedly higher conductance than earlier molecular wires. The origin of high conductance in these wires is fundamentally different from similar molecular devices and suggests a potential strategy for developing highly conducting “doped” molecular wires.

Since their conception, researchers have tried to shrink electronic devices to unprecedented sizes, even to the point of fabricating them from a few molecules. Molecular wires are among the building blocks of such minuscule contraptions, and many researchers have been developing strategies to synthesize highly conductive, stable wires from carefully designed molecules.

A team of researchers from Tokyo Institute of Technology, including Yuya Tanaka, designed a novel molecular wire in the form of a metal electrode-molecule-metal electrode (MMM) junction including a polyyne, an organic chain-like molecule, “doped” with a ruthenium-based unit Ru(dppe)₂. The proposed design, featured in the cover of the Journal of the American Chemical Society, is based on engineering the energy levels of the conducting orbitals of the atoms of the wire, considering the characteristics of gold electrodes.

A major goal in the field of molecular electronics, which aims to use single molecules as electronic components, is to make a device where a quantized, controllable flow of charge can be achieved at room temperature. A first step in this field is for researchers to demonstrate that single molecules can function as reproducible circuit elements such as transistors or diodes that can easily operate at room temperature.

A team led by Latha Venkataraman, professor of applied physics and chemistry at Columbia Engineering and Xavier Roy, assistant professor of chemistry (Arts & Sciences), published a study in Nature Nanotechnology that is the first to reproducibly demonstrate current blockade—the ability to switch a device from the insulating to the conducting state where charge is added and removed one electron at a time—using atomically precise molecular clusters at room temperature.

Bonnie Choi, a graduate student in the Roy group and co-lead author of the work, created a single cluster of geometrically ordered atoms with an inorganic core made of just 14 atoms—resulting in a diameter of about 0.5 nanometers—and positioned linkers that wired the core to two gold electrodes, much as a resistor is soldered to two metal electrodes to form a macroscopic electrical circuit (e.g. the filament in a light bulb).

Under the direction of Latha Venkataraman, associate professor of applied physics at Columbia Engineering, researchers have designed a new technique to create a single-molecule diode, and, in doing so, they have developed molecular diodes that perform 50 times better than all prior designs. Venkataraman’s group is the first to develop a single-molecule diode that may have real-world technological applications for nanoscale devices. Their paper, “Single-Molecule Diodes with High On-Off Ratios through Environmental Control,” is published May 25 in Nature Nanotechnology.

“Our new approach created a single-molecule diode that has a high (250) rectification and a high “on” current (~ 0.1 micro Amps),” says Venkataraman. “Constructing a device where the active elements are only a single molecule has long been a tantalizing dream in nanoscience. This goal, which has been the ‘holy grail’ of molecular electronics ever since its inception with Aviram and Ratner’s 1974 seminal paper, represents the ultimate in functional miniaturization that can be achieved for an electronic device.”

With electronic devices becoming smaller every day, the field of molecular electronics has become ever more critical in solving the problem of further miniaturization, and single molecules represent the limit of miniaturization. The idea of creating a single-molecule diode was suggested by Arieh Aviram and Mark Ratner who theorized in 1974 that a molecule could act as a rectifier, a one-way conductor of electric current. Researchers have since been exploring the charge-transport properties of molecules. They have shown that single-molecules attached to metal electrodes (single-molecule junctions) can be made to act as a variety of circuit elements, including resistors, switches, transistors, and, indeed, diodes. They have learned that it is possible to see quantum mechanical effects, such as interference, manifest in the conductance properties of molecular junctions.

Will it succeed?An open-source investigation suggests that Russia is building a giant laser-based anti-satellite weapon near Zelenchukskaya in the southwest part of the country, Space.com reported. This will allow it a soft-kill option to take down adversarial satellites.

Instead of temporarily blurring sensors, Russia is going full throttle, looking to destroy optical sensors on satellites.

Mr. Shadow is a song composed with Artificial Intelligence. It was created by Flow Machines, a technology that learns different music styles and then makes up its own songs based on what it’s been fed. Although the voice in the song sounds peculiar at times, I could have easily been fooled into thinking a person made this song. You can download Flow Machines onto your apple device to make your own AI music.

What if you could power the smart thermostats, speakers and lights in your home with a kitchen countertop? Stones, such as marble and granite, are natural, eco-friendly materials that many people building or renovating houses already use. Now, in a step toward integrating energy storage with these materials, researchers have fabricated microsupercapacitors onto the surface of stone tiles. The devices, reported in ACS Nano, are durable and easily scaled up for customizable 3D power supplies.

It would be convenient if the surfaces in rooms could charge smart home devices or other small electronics without being connected to the electrical grid. And although stone is a widely used material for floors, countertops and decorative backsplashes, it hasn’t been integrated with energy storage devices, such as batteries and capacitors.

But stones, even those that are polished and seem smooth, have microscopic bumps and divots, making it difficult to adhere electrical components to them. Researchers have recently figured out how to place microsupercapacitors, which have fast charging and discharging rates and excellent power supply storage, onto irregular surfaces with lasers. So, Bongchul Kang and colleagues wanted to adapt this approach to build microsupercapacitors on marble.