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April 2016

March 2016

Symposium EP3: Perovskite PV: opportunities beyond CH3NH3PbI3

Professor David B. Mitzi, Duke University

Currently, the highest performing hybrid perovskite is CH3NH3PbI3. Unfortunately, despite these excellent properties, chemical stability is still a major concern facing hybrid perovskites as they move toward industrial deployment. An inspiring talk from Professor David B. Mitzi at the MRS meeting today has mentioned about the well-defined screening criteria to search for a new perovskite material with better stability. For the first round of selection, the material needs to be earth abundant, low cost and non-toxic. The next round considers the optoelectronic properties of the material including direct bandgap, high absorption, high electron and hole mobility, low strap states and benign grain boundary. For the final round, a solar cell needs to be built from the material and tested for efficiency and stability. As an example of going through the whole new material designing process, Professor David Mitzi group has explored a new perovskite material with the formula (CH3NH3)2Pb(SCN)2I2 (MAPSI) with better stability. More detailed information can be found here.


Innovation in Materials Science

Wednesday-imatsciStephen Forrest, University of Michigan

Moving innovation from the lab to the marketplace: The critical role of academia in the innovation chain

At the second edition of the Materials Research Society’s “Innovation in Materials Science,” or iMatSci, Stephen Forrest of the University of Michigan gave the keynote address. Having co-founded or been a founding participant in numerous companies—including Sensors Unlimited, Epitaxx Inc., NanoFlex Power Corp., Universal Display Corp., and Apogee Photonics Inc.—Forrest was well-positioned to assess what he called the “innovation economic ecosystem” that elicits successful start-up companies.

Among his “lessons learned,” Forrest said, “Your technology is not nearly as important as your market.” He emphasized the importance of using every available resource, including the need for academics to partner with industry and for industry to collaborate with many partners in order to remain competitive.

Forrest serves on the board of directors for Applied Materials as well as on the board of governors of the Technion—Israel Institute of Technology. Realizing a high success rate of innovation in both the United States and Israel, he took a closer look at the innovation-culture established in both regions. Both, he said, have a tolerance for failure and for questioning authority, both work with researchers all over the world. He assessed that in the United States, a robust university-industry relationship is where partnerships begin while in Israel partnerships get established during service in the military. Among the challenges, Forrest said, is the weakening funding basis from the US government and the priority of national security funding in Israel. The availability of capital, Forrest said, is—of course—imperative for the progress of entrepreneurship. The keynote address was aptly followed by a panel discussion on venture funding.

Many innovators were present at this event to demonstrate their technology.


Women in Materials Science & Engineering Breakfast

Wednesday-womenDianne Chong, Boeing Enterprise (retired)

Innovation

Dianne Chong, who served as the vice president of Boeing Research and Technology within the Boeing Engineering, Operation & Technology Organization, said that the definition of “innovation” is often misunderstood. She addressed the Women in Materials Science & Engineering Breakfast on Wednesday morning, talking about the role innovation plays in stability and change.

Changes are happening worldwide, and the “best talent” resides all over the world, Chong said. For companies to remain competitive, they need to adapt to these changes. They also need an element of stability, though, in order to stay in business. For example, at Boeing, the company made 40 airplanes a month while simultaneously disrupting their “stability” in order to do research and development into new products to meet the requests from their customers. The key to the company’s success was to be innovative not only in product development, but also in process and in a business model.

“Process” refers to exploiting existing technology while also exploring new technology. However, “process” also extends to how researchers within the company worked. Materials researchers, for example, formed integrated teams who focused on different aspects of the product. They also worked within a “network” culture where they shared information and ideas within and across departments.

 

Within the current competitive climate, companies must make new products and move them into market within a short timeframe. One way to do this is to license out products to manufacturers and the market that is ready to use them, Chong said. Furthermore, critical to getting a product “ready” for market is to form partnerships with other companies. For example, various part of a particular Boeing airplane can be made up of numerous composites that have been developed by as many as a dozen different companies. This is what Chong refers to as innovation in a business model.

The Women in Materials Science & Engineering Breakfast was sponsored in part by Aldrich Materials Science.


FOCUS Projects and the Future of Energy

Renewable energy is recognized by many as one of the most important needs for the future.  The EE3 talks this morning focused on a particularly promising avenue for energy production: the FOCUS (Full-Spectrum Optimized Conversion and Utilization of Sunlight) projects, funded by ARPA-E.  In particular, it was great to see the talk by Dr. Eric Schiff, the director for FOCUS at ARPA-E.  Dr. Schiff provided an overview and motivation for the FOCUS initiative, and also described the most promising architectures for instrument design.  Both architectures attempt to address a fundamental problem: Different solar energy conversion technologies convert sunlight best at different regions of the solar spectrum.  For example, a photovoltaic cell works well at converting photons with energy greater than its bandgap; however, lower energy photons are not converted to electricity, but either transmit directly through the cell or are converted to waste heat.  In a similar way, the photon energy can be harnessed as thermal energy, but with varying conversion efficiency throughout the solar spectrum.  The focus projects attempt to combine these two conversion processes, and others, onto the same system in order to maximize conversion efficiency throughout the spectrum.  Another benefit of such a tandem system is that the electricity from the photovoltaic may be used immediately, while the power from the solar thermal component may be stored for when the sun is not shining.  These benefits make hybrid solar cells a practical solution to the problem of the indeterminacy of photovoltaic power in a very elegant way.


SM4: Engineering Biointerfaces with Nanomaterials

Francesca Santoro, Stanford University

Pushing scanning electron microscopy to the limit for cell-nanopillar interface interactions

Written by Mary Nora Dickson

Nanoengineered surfaces are an increasingly important tool for the study of cellular biomechanics. However, with standard electron microscopy (EM) techniques, it is impossible to image throughout the interior of a cell, to visualize cell-nanofeature interactions. So Francesca Santoro at Stanford University has developed a new methodology for utilizing scanning electron microscopy (SEM) to generate a three-dimensional (3D) reconstruction of the interior of a cell.

Traditional transmission electron microscopy (TEM) yields high-contrast images, while maintaining the full cell volume (there is no shrinkage). With scanning electron microscopy, one can look at a much larger area, so that the entire cell can be visualized, but cells must be dried out, wrinkling them. Santoro used the sample preparation techniques from TEM, which include introducing stains to improve contrast and embedding samples in a matrix to maintain the volume. She then placed the sample in an SEM, took large-area images of the entire cell, and then used focused ion beam to mill away cell sections. Santoro acquired a stack of images of interior sections of the cell and was able to recreate the internal 3D structure. Changes were observed in the organelles near nanofeatures. The researchers’ novel technique allowed them to finally see the “hidden” interactions of nanofeatures inside the cells.  


SM5: Surfaces and Interfaces for Biomaterials

Diego Mantovani, Université Laval

Silver-containing diamond-like carbon as highly stable antibacterial coatings

Written by Mary Nora Dickson

Hospital-acquired infections cost thousands of lives each year. So why are they so hard to prevent? Surfaces in hospital rooms can harbor dangerous bacteria, which are then easily transferred to patients. Commercial antibiotic surfaces are not stable enough against mechanical wear or cleaning chemicals. So Maxime Cloutier and Diego Mantovani, at Université Laval in Canada, have developed a robust, antibacterial coating that can be applied to stainless steel surfaces.

The key is their composite material: silver nanoclusters embedded in a diamond-like carbon. This material combines the antibacterial properties of nanosilver, but is scratch-resistant and solvent-resistant. The research group utilizes a plasma deposition process to covalently bond the coating to the substrate. By tuning the plasma conditions, the researchers were able to optimize the thickness, distribution of nanosilver, and the mechanical properties of the diamond-like carbon. They plan to test these surfaces in clinical environments soon.


SM1: Liquid Crystalline Materials—Displays and Beyond

Helen F. Gleeson, University of Leeds

Liquid crystal contact lenses with graphene electrodes and switchable focus

Written by Devesh Mistry

Presbyopia is an age-related condition of the eye which affects people over 55 years old. The condition reduces a person’s ability to focus on nearby objects and is caused by the focusing lens of the eye becoming stiffer with age. Current treatments such as reading glasses and bifocal contact lenses all have visual compromises.

Inspired by the ubiquity of presbyopia, Gleeson and her team have developed a contact lens technology which provides a variable focus as an electric field is applied across a liquid crystal lens. The technology utilizes a graphene as opposed to an indium-tin oxide (ITO) electrode. ITO is a conventional transparent electrode material; however, graphene has the benefit of being flexible whereas ITO is brittle. 

As the wearer of such contact lenses chooses to focus on a close object, the contact lens is turned on and the effective refractive index and hence optical power of the liquid crystal lens changes. This allows the user to focus on the nearby object. Much work is still to be done to investigate polarization independent options. Gleeson proposed using the dark conglomerate liquid crystal phase which has a voltage dependent refractive index but which also remains optically isotropic.


SM2: Bioinspired Dynamic Materials—Synthesis, Engineering and Applications

Tasuku Nakajima, Hokkaido University

Advanced functional hydrogels based on reversible sacrificial bonds.

Written by Devesh Mistry

Hydrogels are an exciting category of soft materials with many potential applications. However, current hydrogels lack strength; that is, they fail at low stresses. As such, hydrogels are not currently suitable as structural materials. Tasuku Nakajima of Hokkaido University has been exploring the use of double networks to strengthen hydrogels and introduce further properties such as self-healing.

Nakajima has used a two-step process to produce hydrogels with two separate networks. The first network is formed from a dilute polymer which is densely crosslinked. A second network is then formed within the first. This network is much more condensed, but has a far lower crosslink density. On application of a stress, the energy is dissipated by the brittle bonds of the first network, preserving the shape of the hydrogel. In a dramatic series of videos, Nakajima showed how the hydrogel could be driven over with a truck with no apparent damage. This is remarkable for a material which is 90% water!

The breaking of the brittle bonds is an irreversible process, so subsequent stresses destroy the hydrogel. To produce a self-healing hydrogel, Nakajima replaced the brittle bonds with ionic bonds capable of reforming. Other hydrogel systems involving lamellar structures displayed tunable Bragg reflections.


EE11: Caloric Materials for Renewable Energy Applications

Qiming Zhang, The Pennsylvania State University

Developing Dielectric Materials with Giant Electrocaloric (EC) Response and for Practical EC Cooling

Written by Tine Naerland

Electrocaloric effect (ECE) is the ability of a dielectric to change its temperature and entropy as an electric field is applied and released. It provides an effective means to realize solid-state cooling devices that are environmentally benign and potentially highly energy efficient. Large electrocaloric effect over a broad temperature range has been obtained in relaxor ferroelectric polymers, nanocomposites, and ferroelectric ceramics, under high electric fields. The easy control of the electric signals and large ECE enable a variety of cooling and thermal management device configurations, from micro-coolers, to portable, and large size cooling devices, to be realized.


EP11: Novel Materials for End-of-Roadmap Devices in Logic, Power and Memory

Susan Fullerton, University of Pittsburgh

2D Electrolytes for the Development of 2D Crystal Memory

Written by Tine Naerland

Susan Fullerton of the University of Pittsburgh highlighted a new approach to memory that relies on the electrostatic gating of two-dimensional (2D) crystals using lithium ions. Unlike resistive random access memory (RRAM), where conductive filaments are formed and broken to create the 0 and 1 states, this memory concept relies on the physisorption of ions to the 2D crystal and there is no charge exchange. The advantages of this approach is less processing and potentially smaller devices compared to conventional technology. Drawbacks are lower switching speed than predicted. Many efforts are, however, currently underway to understand the materials properties that are limiting the switching speed.