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.


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.


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.



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.


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.


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.


Mimicking Nature’s Camouflage

In the world of ocean life, the cuttlefish is the king of camouflage. The cuttlefish’s ability to disguise itself, becoming virtually invisible to the naked eye, is an amazing quality that is very difficult to engineer. But with a little inspiration from marine animal, engineers from the University of Nebraska-Lincoln (UNL) have developed a design that mimics patters and textures in a flash.

Within seconds of light exposure, the new structure begins to replicate color and texture of the surrounding environment. While engineers have developed camouflaging materials before, this new design responds to much lower-intensity light and at faster rates than the few predecessors that exist.

“This is a relatively new community of research,” said Li Tan, associate professor of mechanical and materials engineering. “Most of the people (in it) are inspired by the cuttlefish, whose skin changes color and texture, as well.”


Engineers have developed a way to visualize the optical properties of objects that are thousands of times small than a grain of sand.Source: YouTube/Stanford University

Engineers have developed a way to visualize the optical properties of objects that are thousands of times small than a grain of sand.
Source: YouTube/Stanford University

In order to develop high efficiency solar cells and LEDs, researchers need to see how light interacts with objects on the nanoscale. Unfortunately, light is tricky to visualize in relation to small-scale objects.

Engineers from Stanford University, in collaboration with FOM Institute AMOLF, have developed a next-gen optical method to produce high-resolution, 3D images of nanoscale objects. This allows researchers to visualize the optical properties of objects that are several thousandths the size of a grain of sand.

The teams achieved this by combining two technologies: cathodluminescence and tomography.


People in remote locations can now detect viruses and bacteria without leaving their homes.Image: Scientific Reports

People in remote locations can now detect viruses and bacteria without leaving their homes.
Image: Scientific Reports

A team of researchers has developed a device that aims to provide adequate and efficient health care to those who live in remote regions with limited access to medical professionals.

The device utilizes biosensing to detected such viruses and bacteria as HIV and Staph from remote locations. Patients simply take a small blood or saliva sample and apply it to a film made of cellulose paper—each of which is designed to detect a specific bacteria or virus.

This from Popular Science:

The patient would then use a smartphone app to take a picture of the sample and send it to a doctor for diagnosis. Medical professionals, no matter where they are, would receive the cell-fies and look at the bacterial biomarkers in the sample to diagnose the disease. The film is sensitive, disposable, and much cheaper to produce than similar biosensing films.


The Rise of Quantum Dots

Andrea Guenzel, ECS Publications Specialist, recently spotted a CNN article on quantum dots and how they’re poised to change industry.

The technology behind Edison’s incandescent blub may be a thing of the past, but the warm, gentle glow that it produced may be making its way back into your living room.

But we’re not scrapping the advancements in LEDs and regressing to old technology to do this. Instead, we’re turning our attention to quantum dots—the tiny crystal-like particles that are 10,000 times smaller than the width of human hair.

And the dots’ applications do not end simply at bulbs. These tiny bursts of light are expected to impact displays, solar cells, and cancer imaging equipment as well.


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