New Research Could Lead to Better LEDs

Research and improvements in LED technology have impacted everything from television screens to life-changing electronic vision. With the vast potential of LED technology, scientists are looking to improve the efficiency of LEDs as well as simplify the manufacturing process.

A team at the California Nanosystems Institute at UCLA is focusing on the science of electroluminescence to accomplish this by demonstrating this process from multilayer molybdenum disulfide.

In the new study, UCLA’s Xianfeng Duan was able to show that the multilayer molybdenum disulfide—the relatively cheap and easy to produce material—can, contrary to popular belief, show strong luminescence qualities when electrical current passes through.

Prior to focusing his attention on building better LEDs, Duan focused his research efforts on topics such as graphene’s applications in transistors and applying nanoscale materials to solar energy efforts.

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Printable Functional Materials

Potential technical applications of printable functional inks.

The videos and information in this post relate to an ECS Journal of Solid State Science and Technology focus issue called: Printable Functional Materials for Electronics and Energy Applications.

(Read/download the focus issue now. It’s entirely free.)

Printing technologies in an atmospheric environment offer the potential for low-cost and materials-efficient alternatives for manufacturing electronics and energy devices such as luminescent displays, thin-film transistors, sensors, thin-film photovoltaics, fuel cells, capacitors, and batteries. Significant progress has been made in the area of printable functional organic and inorganic materials including conductors, semiconductors, and dielectric and luminescent materials.

These new printable functional materials have and will continue to enable exciting advances in printed electronics and energy devices. Some examples are printed amorphous oxide semiconductors, organic conductors and semiconductors, inorganic semiconductor nanomaterials, silicon, chalcogenide semiconductors, ceramics, metals, intercalation compounds, and carbon-based materials.

A special focus issue of the ECS Journal of Solid State Science and Technology was created about the publication of state-of-the-art efforts that address a variety of approaches to printable functional materials and device. This focus issue, consisting of a total of 15 papers, includes both invited and contributed papers reflecting recent achievements in printable functional materials and devices.

The topics of these papers span several key ECS technical areas, including batteries, sensors, fuel cells, carbon nanostructures and devices, electronic and photonic devices, and display materials, devices, and processing. The overall collection of this focus issue covers an impressive scope from fundamental science and engineering of printing process, ink chemistry and ink conversion processes, printed devices, and characterizations to the future outlook for printable functional materials and devices.

The video below demonstrates Printed Metal Oxide Thin-Film Transistors by J. Gorecki, K. Eyerly, C.-H. Choi, and C.-H. Chang, School of Chemical, Biological and Environmental Engineering, Oregon State University.

Step-by-step explanation of the video:

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New Material to Make Better Transistors

According to new research, black phosphorus may have the potential to outpace silicon.Image:

According to new research, black phosphorus may have the potential to outpace silicon.
Image: McGill University

We’re one step closer to atomic layer transistors due to recent research by a team of McGill University and Université de Montréal researchers. The new findings are the result of multidisciplinary work that yielded evidence that the material black phosphorus may make it possible to pack more transistors on a chip.

Researchers from McGill University joined with ECS’s Richard Martel in the Université de Montréal’s Department of Chemistry to examine if black phosphorus could tackle the prominent issue in the electronics field of designing energy-efficient transistors.

Similar to graphite, black phosphorus can be separate easily into single atomic layers to allow for thin transistors. When researchers are able to produce thinner transistors, they are also more efficient.

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Graphene Flexes Its Electronic Muscles

Carbon nanotubes, seamless cylinders of graphene, do not display a total dipole moment. While not zero, the vector-induced moments cancel each other out.Rice University

Carbon nanotubes, seamless cylinders of graphene, do not display a total dipole moment. While not zero, the vector-induced moments cancel each other out.
Image: Rice University

Theoretical physicist at both Rice University and institutes in Russia have concluded that the best way to control graphene’s electrical qualities is to flex the material.

Rice University’s Boris Yakobson and his lab are collaborating with Moscow researchers to calculate the electrical properties of nanocones, which should be universal for other forms of graphene.

(PS: You can take a look at some of Yakobson’s past meeting abstracts in the Digital Library.)

This from Rice University:

The researchers discovered it may be possible to access what they call an electronic flexoelectric effect in which the electronic properties of a sheet of graphene can be manipulated simply by twisting it a certain way. The work will be of interest to those considering graphene elements in flexible touchscreens or memories that store bits by controlling electric dipole moments of carbon atoms, the researchers said.

Read the full article here.

“While the dipole moment is zero for flat graphene or cylindrical nanotubes, in between there is a family of cones, actually produced in laboratories, whose dipole moments are significant and scale linearly with cone length,” Yakobson said.

ICYMI: Check out our podcast, “A Word About Nanocarbons,” featuring another Rice University carbon nanotube expert, Dr. Bruce Weisman.

Interested in carbon nanotubes, fullerenes, and nanocarbons? Make sure to check out ECS’s Nanocarbons Division!

Analyzing Thin Film Break-Up

The open-source code, WulffMaker, is available as a Wolfram computable document format file or a Mathematica notebook.Image: MIT/Rachel Zucker

The open-source code, WulffMaker, is available as a Wolfram computable document format file or a Mathematica notebook.
Image: MIT/Rachel Zucker

Recent PhD recipient and past ECS student member, Rachel Zucker, examined one of the most complex issues in materials science and has developed a range of mathematical solutions to explain the phenomena known as “dewetting” in solid films. In defense of her thesis, Zucker modeled dewetting in microscale and nanoscale thin films.

Dewetting can be boiled down to the general break-up of material due to excess surface energy. Zucker’s development provides us with not only a new understanding of this phenomenon, but also a way to simulate it. When analyzing solid state dewetting, issues becomes very prominent as engineers attempt to make products with smaller and smaller features.

“The big takeaway is: One, we can write down formulation of this problem; two, we can implement a numerical method to construct the solutions; three, we can make a direct comparison to experiments; and that strikes me as what a thesis should be — the complete thing — formulation, solution, comparison, conclusion,” said W. Craig Carter, MIT professor and Zucker’s co-adviser.

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Printable Functional Materials

Potential technical applications of printable functional inks.

The video and information in this post relate to an ECS Journal of Solid State Science and Technology focus issue called: Printable Functional Materials for Electronics and Energy Applications.

(Read/download the focus issue now. It’s entirely free.)

Printing technologies in an atmospheric environment offer the potential for low-cost and materials-efficient alternatives for manufacturing electronics and energy devices such as luminescent displays, thin-film transistors, sensors, thin-film photovoltaics, fuel cells, capacitors, and batteries. Significant progress has been made in the area of printable functional organic and inorganic materials including conductors, semiconductors, and dielectric and luminescent materials.

These new printable functional materials have and will continue to enable exciting advances in printed electronics and energy devices. Some examples are printed amorphous oxide semiconductors, organic conductors and semiconductors, inorganic semiconductor nanomaterials, silicon, chalcogenide semiconductors, ceramics, metals, intercalation compounds, and carbon-based materials.

A special focus issue of the ECS Journal of Solid State Science and Technology was created about the publication of state-of-the-art efforts that address a variety of approaches to printable functional materials and device. This focus issue, consisting of a total of 15 papers, includes both invited and contributed papers reflecting recent achievements in printable functional materials and devices.

The topics of these papers span several key ECS technical areas, including batteries, sensors, fuel cells, carbon nanostructures and devices, electronic and photonic devices, and display materials, devices, and processing. The overall collection of this focus issue covers an impressive scope from fundamental science and engineering of printing process, ink chemistry and ink conversion processes, printed devices, and characterizations to the future outlook for printable functional materials and devices.

The video below show demonstrates Inkjet Printed Conductive Tracks for Printed Electronic conducted by S.-P. Chen, H.-L. Chiu, P.-H. Wang, and Y.-C. Liao, Department of Chemical Engineering, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei 10617, Taiwan.

Step-by-step explanation of the video:

For printed electronic devices, metal thin film patterns with great conductivities are required. Three major ways to produce inkjet-printed metal tracks will be shown in this video.

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Novel Concrete Can Heal Itself

Concrete is the world’s most popular building material, but the material’s durability deteriorates over years allowing for potentially devastating consequences. One researcher from Delft University of Technology, Henk Jonkers, has made it his mission to combat this issue by developing a “living concrete.”

Jonkers’ development has produced a new type of concrete that can fix its own cracks by using a bacteria healing agent.

“We are combining nature with construction materials,” said Jonkers.

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riceuniversity

Researchers were able to deform the molybdenum disulfide without breaking it.
Image: Nano Letters

Many labs have had their eye on molybdenum disulfide recently due to its promising semiconducting properties. Rice University has also turned its attention toward this 2D material and its interesting sandwich structure. During their studies, the researchers have concluded that under certain conditions, molybdenum disulfide can transform from the consistency of peanut brittle to that of taffy.

According to their research, the scientists state that when exposed to sulfur-infused gas at the right temperature and pressure, molybdenum disulfide takes on the qualities of plastic. This development has the potential to have a high impact in the world of materials science.

The structure of the molybdenum disulfide is similar to a sandwich, with layers of sulfur above and below the molybdenum atoms. When the two sheets join at different angles “defective” arrangements—or dislocations—are formed.

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One of the world’s strongest natural materials has met one of the strongest artificial materials.

Researchers from the University of Trento, Italy conduced an experiment where they sprayed spiders—producers of naturally strong silk—with carbon-based graphene. Why? Curiosity, of course—the backbone of much great science.

From the experiment, the researchers found that some spiders produced silk that was 3.5 times tougher and stronger than the best naturally produced silk.

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New Type of Graphene Aerogel (Video)

focus-issue-boxLogan Streu, ECS Content Associate & Assistant to the CCO, recently spotted an article out of Lawrence Livermore National Laboratory detailing a new type of graphene aerogel that could improve energy storage, sensors, nanoelectronics, catalysis, and separations.

The researchers are creating graphene aerogel microlattics through a 3D printing process known as direct ink wetting.

This from Lawrence Livermore National Laboratory:

The 3D printed graphene aerogels have high surface area, excellent electrical conductivity, are lightweight, have mechanical stiffness and exhibit supercompressibility (up to 90 percent compressive strain). In addition, the 3D printed graphene aerogel microlattices show an order of magnitude improvement over bulk graphene materials and much better mass transport.

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