New method from MIT’s research enterprise in Singapore paves the way for improved optoelectronic and 5G devices.
LEES researcher Silicon III V wafer Web
A LEES researcher reviews a 200 mm Silicon III-V wafer. Photo: SMART

The Singapore-MIT Alliance for Research and Technology (SMART), MIT’s research enterprise in Singapore, has announced the successful development of a commercially viable way to manufacture integrated silicon III-V chips with high-performance III-V devices inserted into their design.

In most devices today, silicon-based CMOS chips are used for computing, but they are not efficient for illumination and communications, resulting in low efficiency and heat generation. This is why current 5G mobile devices on the market get very hot upon use and can shut down after a short time.

This is where III-V semiconductors are valuable. III-V chips are made with compounds including elements in the third and fifth columns of the periodic table, such as gallium nitride (GaN) and indium gallium arsenide (InGaAs). Due to their unique properties, they are exceptionally well-suited for optoelectronics (such as LEDs) and communications (such as 5G wireless), boosting efficiency substantially.

“By integrating III-V into silicon, we can build upon existing manufacturing capabilities and low-cost volume production techniques of silicon and include the unique optical and electronic functionality of III-V technology,” says Eugene Fitzgerald, CEO and director of SMART and the Merton C. Flemings-SMA Professor of Materials Science and Engineering at MIT. “The new chips will be at the heart of future product innovation and power the next generation of communications devices, wearables, and displays.”

Kenneth Lee, senior scientific director of the SMART Low Energy Electronic Systems (LEES) research program, adds: “Integrating III-V semiconductor devices with silicon in a commercially viable way is one of the most difficult challenges faced by the semiconductor industry, even though such integrated circuits have been desired for decades. Current methods are expensive and inefficient, which is delaying the availability of the chips the industry needs. With our new process, we can leverage existing capabilities to manufacture these new integrated silicon III-V chips cost-effectively and accelerate the development and adoption of new technologies that will power economies.”

The new technology developed by SMART builds two layers of silicon and III-V devices on separate substrates and integrates them vertically together within a micron, which is 1/50th the diameter of a human hair. The process can use existing 200 micrometer manufacturing tools, which will allow semiconductor manufacturers in Singapore and around the world to make new use of their current equipment. Today, the cost of investing in a new manufacturing technology is in the range of tens of billions of dollars; the new integrated circuit platform is highly cost-effective, and will result in much lower-cost novel circuits and electronic systems.

SMART is focusing on creating new chips for pixelated illumination/display and 5G markets, which has a combined potential market of over $100 billion. Other markets that SMART’s new integrated silicon III-V chips will disrupt include wearable mini-displays, virtual reality applications, and other imaging technologies.

The patent portfolio has been exclusively licensed by New Silicon Corporation (NSC), a Singapore-based spinoff from SMART. NSC is the first fabless silicon integrated circuit company with proprietary materials, processes, devices, and design for monolithic integrated silicon III-V circuits.

SMART’s new integrated Silicon III-V chips will be available next year and expected in products by 2021.

SMART’s LEES Interdisciplinary Research Group is creating new integrated circuit technologies that result in increased functionality, lower power consumption, and higher performance for electronic systems. These integrated circuits of the future will impact applications in wireless communications, power electronics, LED lighting, and displays. LEES has a vertically-integrated research team possessing expertise in materials, devices, and circuits, comprising multiple individuals with professional experience within the semiconductor industry. This ensures that the research is targeted to meet the needs of the semiconductor industry both within Singapore and globally.

Singapore-MIT Alliance for Research and Technology | MIT News
October 3, 2019

Monday, 29 October 2018 14:50

Solving a multi-million dollar problem

BP chemist details new X-ray technologies and sample chambers that are yielding insights into fighting metal corrosion, improving catalytic reactions and more.
Materials Day Matt Kulzick Keynote 8701 DP Web
BP Amoco Chemical Company Senior Research Chemist Dr. Matthew Kulzick outlines advances in imaging technology during the MIT MRL Materials Day Symposium on Wednesday, Oct. 10, 2018. Photo, Denis Paiste, Materials Research Laboratory.

New electron microscopy techniques can help solve corrosion problems that are worth millions of dollars to industrial companies, BP Amoco Chemical Company Senior Research Chemist Dr. Matthew Kulzick told the MIT MRL Materials Day Symposium on Wednesday, Oct. 10, 2018.

“Materials Science is critical. It’s really material in the financial sense,” Kulzick said. “Solutions demand timely and accurate information. If I’m going to solve a problem, I’ve got to know what’s actually going on, and to do that I need all of these different interrelated tools to be able to go in and find out what’s happening in systems that are important to us.”

New X-ray technologies and sample chambers are producing stunning images at 20-nanometer scale showing highly localized composition of materials. “The current evolution of tools is spectacular,” he said.

Beginning in 2003, Kulzick built a new inorganic characterization capability for BP Amoco Chemical Company, MRL Associate Director Mark Beals said in introducing Kulzick. Kulzick has been working with Nestor J. Zaluzec, a senior scientist at Argonne National Laboratory, as well as with the BP International Center for Advanced Materials [ICAM], whose partners include the University of Manchester, Imperial College London, the University of Cambridge, and the University of Illinois Urbana–Champaign.

Transformative techniques

He outlined advances in imaging technology such as the π Steradian Transmission X-ray Detection System developed at the U.S. Department of Energy’s Argonne National Laboratory and advances in sample holder technology that BP developed collaboratively with Protochips that allow analysis of materials in gas or liquid filled chambers. Microscopic measurements using these holders, or cells, which can include micro-electro-mechanical systems (MEMS), are called in situ techniques.

“A number of years ago we worked with Protochips, and we modified that holder technology to allow the X-rays coming out of that system to get to the detector,” Kulzick explained. Images of a palladium and copper-based automotive catalyst from four different generations of Energy-dispersive X-ray technology illustrated the evolution from images lacking in detail to a nanoscale compositional image acquired in just 2.5 seconds that shows the location of palladium in the chemical structure. “So it’s really transformative in understanding what’s happening chemically at the nanoscale,” Kulzick says.

Placing a closed cell filled with hydrogen gas to simulate reduction of the catalyst inside a transmission electron microscope produced images that showed palladium particles remained unaffected while copper particles either migrated toward palladium particles or clustered together with other copper particles. “We can actually observe the changes that are happening in that localized area under reduction, and this is extremely important if we really want to understand what’s happening,” Kulcizk says. “All of that diversity is occurring in what amounts to roughly a square micron of area on the surface of the material.”

Materials Day Matt Kulzick Keynote 8699 DP Featured
BP Amoco Chemical Company Senior Research Chemist Dr. Matthew Kulzick addresses the MIT MRL Materials Day Symposium on Wednesday, Oct. 10, 2018. Photo, Denis Paiste, Materials Research Laboratory.

“Just imagine what I could do with this kind of technology with regard to understanding how to activate a catalyst, how to regenerate a catalyst,” Kulzick said.

Techniques developed by Prof. M. Grace Burke at the University of Manchester in the UK allow observation of chemical changes in a piece of metal over a period of hours such as dissolving a manganese sulfide inclusion from a small piece of stainless steel soaking in water, Kulzick said. “This proved a point for her with regards to corrosion mechanisms that are relevant in the nuclear industry where they worry about what’s initiating crack formation and which she has argued for years that attack of the manganese sulfide by water was one of the underlying mechanisms,” he said.

Direct electron capture cameras

A significant advance for analyzing organic materials is direct electron capture cameras, Kulzick said. “One of the problems with bombarding things with electrons is beam damage, so you want to use as little as you can with the right energies. The direct electron capture cameras allowed us to reduce that dose,” he said.

For example, Qian Chen, Assistant Professor of Materials Science and Engineering, at the University of Illinois Urbana–Champaign, has used this enhanced sensitivity and lower dose radiation to a do a series of images at differing tilts to generate a three-dimensional image of a polymer membrane. Computational image analysis becomes important with these 3D structural images. “Without the ability to digitize that material like we’ve done, we would never be able to understand this diversity of structure and make it more rational,” Kulzick said.

Further analysis of the polymer membrane – soaked in a solution of zinc and lead – with Analytical Electron Microscope (AEM) techniques developed by Zaluzec at Argonne National Laboratory revealed that different ions enter into the polymer membrane at different locations. The next step is to understand how ions interact with the membrane structure and how that impacts permeation in the systems, Kulzick said. Chen also analyzed the polymer membrane in water inside a graphene cell, he said, and that work showed swelling of the membrane.

“We hope to put all these pieces together and form a really detailed understanding of how a system like this functions,” he said.

back to newsletterDenis Paiste, Materials Research Laboratory
October 30, 2018



Thursday, 16 August 2018 15:20




Carl Thompson


Carl V. Thompson
Professor, Materials Science & Engineering
and Director,
Materials Research Laboratory

Brian Storey

Accelerating Materials Design and Discovery for Electric Vehicles

Brian Storey
Director, Accelerated Materials
Design & Discovery

TOYOTA Research Institute

Elsa Olivetti

Text and Data Mining for Material Synthesis

Elsa Olivetti
Associate Professor
Materials Science & Engineering, MIT
Rafael Gomez-Bombarelli

Learning Matter: Materials Design Through Atomistic Simulations and Machine Learning

Rafael Gomez-Bombarelli
Assistant Professor
Materials Science & Engineering, MIT
Advancing Chemical Development Through Process Intensification, Automation, and Machine Learning

Klavs F. Jensen
Chemical Engineering and
Materials Science & Engineering, MIT
Abstract & Bio
Ju Li
Elastic Strain Engineering for Unprecedented Properties

Ju Li
Nuclear Science & Engineering and
Materials Science and Engineering, MIT
Abstract & Bio
Machine Learning in Optics: From Spectrum Reconstruction to Metasurface Design

Juejun Hu
Associate Professor
Materials Science & Engineering, MIT
Abstract & Bio
asu ozdaglar
Computing at MIT

Asu Ozdaglar
Professor & Department Head
Electrical Engineering & Computer Science, MIT
Abstract & Bio

Brian Storey

Dr. Brian Storey
Director, Accelerated Materials Design & Discovery

Toyota Research Institute

Accelerating Materials Design and Discovery for Electric Vehicles

Elsa Olivetti

Elsa Olivetti
Associate Professor
Department of Materials Science & Engineering, MIT

Text and Data Mining for Material Synthesis

Bombarelli Rafael Gomez-Bombarelli
Assistant Professor

Department of Materials Science & Engineering, MIT

Learning matter: Materials Design Through Atomistic Simulations and Machine Learning

Klavs Klavs F. Jensen
Department of Chemical Engineering and
Department of Materials Science & Engineering, MIT

Advanced Chemical Development Through Process Intensification, Automation, and Machine Learning

Ju Li Ju Li
Department of Nuclear Science & Engineering and
Department of Materials Science & Engineering, MIT

Elastic Strain Engineering for Unprecedented Properties


Juejun Hu
Associate Professor
Department of Materials Science & Engineering, MIT

Machine Learning in Optics: From Spectrum Reconstruction to Metasurface Design

asu ozdaglar

Asu Ozdaglar
Professor & Department Head
Department of Electrical Engineering & Computer Science, MIT

Computing at MIT

CarlCarl V. Thompson
Materials Research Laboratory
Stavros Salapatas Professor of Materials Science & Engineering, MIT






Juejun (JJ) Hu
Juejun (JJ) Hu

SPIE Professional magazine honored Associate Professor of Materials Science and Engineering Juejun (JJ) Hu with one of three 2019 Early Career Achievement Awards in recognition of his original contributions to integrated optics and photonics through innovative material and device engineering. SPIE is the international society for optics and photonics, an educational not-for-profit organization founded in 1955 to advance light-based science, engineering, and technology.

Read more

back to newsletterMarch 26, 2019

Innovative approach to controlling magnetism could lead to next-generation memory and logic devices.
MIT Controlling Spintronics Beach Web
Illustration shows how hydrogen ions (red dots), controlled by an electric voltage, migrate through an intermediate material to change the magnetic properties of an adjacent magnetic layer (shown in green). Image: courtesy of the researchers, edited by MIT News

A new approach to controlling magnetism in a microchip could open the doors to memory, computing, and sensing devices that consume drastically less power than existing versions. The approach could also overcome some of the inherent physical limitations that have been slowing progress in this area until now.

Researchers at MIT and at Brookhaven National Laboratory have demonstrated that they can control the magnetic properties of a thin-film material simply by applying a small voltage. Changes in magnetic orientation made in this way remain in their new state without the need for any ongoing power, unlike today’s standard memory chips, the team has found.

The new finding, reported Nov. 12, 2018, in the journal Nature Materials, in a paper by Geoffrey Beach, a professor of materials science and engineering and co-director of the MIT Materials Research Laboratory; graduate student Aik Jun Tan; and eight others at MIT and Brookhaven.

Spin doctors

As silicon microchips draw closer to fundamental physical limits that could cap their ability to continue increasing their capabilities while decreasing their power consumption, researchers have been exploring a variety of new technologies that might get around these limits. One of the promising alternatives is an approach called spintronics, which makes use of a property of electrons called spin, instead of their electrical charge.

Because spintronic devices can retain their magnetic properties without the need for constant power, which silicon memory chips require, they need far less power to operate. They also generate far less heat — another major limiting factor for today’s devices.

But spintronic technology suffers from its own limitations. One of the biggest missing ingredients has been a way to easily and rapidly control the magnetic properties of a material electrically, by applying a voltage. Many research groups around the world have been pursuing that challenge.

Previous attempts have relied on electron accumulation at the interface between a metallic magnet and an insulator, using a device structure similar to a capacitor. The electrical charge can change the magnetic properties of the material, but only by a very small amount, making it impractical for use in real devices. There have also been attempts at using ions instead of electrons to change magnetic properties. For instance, oxygen ions have been used to oxidize a thin layer of magnetic material, causing an extremely large change in magnetic properties. However, the insertion and removal of oxygen ions causes the material to swell and shrink, causing mechanical damage that limits the process to just a few repetitions — rendering it essentially useless for computational devices.

The new finding demonstrates a way around that, by using hydrogen ions instead of the much larger oxygen ions used in previous attempts. Since the hydrogen ions can zip in and out very easily, the new system is much faster and provides other significant advantages, the researchers say.

Because the hydrogen ions are so much smaller, they can enter and exit from the crystalline structure of the spintronic device, changing its magnetic orientation each time, without damaging the material. In fact, the team has now demonstrated that the process produces no degradation of the material after more than 2,000 cycles. And, unlike oxygen ions, hydrogen can easily pass through metal layers, which allows the team to control properties of layers deep in a device that couldn’t be controlled in any other way.

“When you pump hydrogen toward the magnet, the magnetization rotates,” Tan says. “You can actually toggle the direction of the magnetization by 90 degrees by applying a voltage — and it’s fully reversible.” Since the orientation of the poles of the magnet is what is used to store information, this means it is possible to easily write and erase data “bits” in spintronic devices using this effect.

Beach, whose lab discovered the original process for controlling magnetism through oxygen ions several years ago, says that initial finding unleashed widespread research on a new area dubbed “magnetic ionics,” and now this newest finding has “turned on its end this whole field.”

“This is really a significant breakthrough,” says Chris Leighton, the Distinguished McKnight University Professor in the Department of Chemical Engineering and Materials Science at the University of Minnesota, who was not involved in this work. “There is currently a great deal of interest worldwide in controlling magnetic materials simply by applying electrical voltages. It’s not only interesting from the fundamental side, but it’s also a potential game-changer for applications, where magnetic materials are used to store and process digital information.”

Leighton says, “Using hydrogen insertion to control magnetism is not new, but being able to do that in a voltage-driven way, in a solid-state device, with good impact on the magnetic properties — that is pretty significant!” He adds, “this is something new, with the potential to open up additional new areas of research. … At the end of the day, controlling any type of materials function by literally flipping a switch is pretty exciting. Being able to do that quickly enough, over enough cycles, in a general way, would be a fantastic advance for science and engineering.”

Essentially, Beach explains, he and his team are “trying to make a magnetic analog of a transistor,” which can be turned on and off repeatedly without degrading its physical properties.

Just add water

The discovery came about, in part, through serendipity. While experimenting with layered magnetic materials in search of ways of changing their magnetic behavior, Tan found that the results of his experiments varied greatly from day to day for reasons that were not apparent.

Eventually, by examining all the conditions during the different tests, he realized that the key difference was the humidity in the air: The experiment worked better on humid days compared to dry ones. The reason, he eventually realized, was that water molecules from the air were being split up into oxygen and hydrogen on the charged surface of the material, and while the oxygen escaped to the air, the hydrogen became ionized and was penetrating into the magnetic device — and changing its magnetism.

The device the team has produced consists of a sandwich of several thin layers, including a layer of cobalt where the magnetic changes take place, sandwiched between layers of a metal such as palladium or platinum, and with an overlay of gadolinium oxide, and then a gold layer to connect to the driving electrical voltage.

The magnetism gets switched with just a brief application of voltage and then stays put. Reversing it requires no power at all, just short-circuiting the device to connect its two sides electrically, whereas a conventional memory chip requires constant power to maintain its state. “Since you’re just applying a pulse, the power consumption can go way down,” Beach says.

The new devices, with their low power consumption and high switching speed, could eventually be especially useful for devices such as mobile computing, Beach says, but the work is still at an early stage and will require further development.

“I can see lab-based prototypes within a few years or less,” he says. Making a full working memory cell is “quite complex” and might take longer, he says.

The work was supported by the National Science Foundation through the Materials Research Science and Engineering Center (MRSEC) Program.

David L. Chandler | MIT News Office
November 12, 2018

Wednesday, 28 February 2018 14:34

Study reveals why polymer stents failed

Microscopic flaws in material structure can lead to stent deformation after implantation.
MIT Stent Failure PRESS WEB
Researchers hope that their work will lead to a new approach to designing and evaluating polymer stents and other types of degradable medical devices. Image, Pei-Jiang Wang

Many patients with heart disease have a metal stent implanted to keep their coronary artery open and prevent blood clotting that can lead to heart attacks. One drawback to these stents is that long-term use can eventually damage the artery.

Several years ago, in hopes of overcoming that issue, a new type of stent made from biodegradable polymers was introduced. Stent designers hoped that these devices would eventually be absorbed by the blood vessel walls, removing the risk of long-term implantation. At first, these stents appeared to be working well in patients, but after a few years these patients experienced more heart attacks than patients with metal stents, and the polymer stents were taken off the market.

MIT researchers in the Institute for Medical Engineering and Science and the Department of Materials Science and Engineering have now discovered why these stents failed. Their study also reveals why the problems were not uncovered during the development process: The evaluation procedures, which were based on those used for metal stents, were not well-suited to evaluating polymer stents.

“People have been evaluating polymer materials as if they were metals, but metals and polymers don’t behave the same way,” says Elazer Edelman, the Thomas D. and Virginia W. Cabot Professor of Health Sciences and Technology at MIT. “People were looking at the wrong metrics, they were looking at the wrong timescales, and they didn’t have the right tools.”

The researchers hope that their work will lead to a new approach to designing and evaluating polymer stents and other types of degradable medical devices.

“When we use polymers to make these devices, we need to start thinking about how the fabrication techniques will affect the microstructure, and how the microstructure will affect the device performance,” says lead author Pei-Jiang Wang, a Boston University graduate student who is doing his PhD thesis with Edelman.

Edelman is the senior author of the paper, which appears in the Proceedings of the National Academy of Sciences the week of Feb. 26. Other authors include MIT research scientist Nicola Ferralis, MIT professor of materials science and engineering Jeffrey Grossman, and National University of Ireland Galway professor of engineering Claire Conway.

Microstructural flaws

The degradable stents are made from a polymer called poly-l-lactic acid (pLLA), which is also used in dissolvable sutures. Preclinical testing (studies done in the lab and with animal models) did not reveal any cause for concern. In human patients the stents appeared stable for the first year, but then problems began to arise. After three years, over 10 percent of patients had experienced a heart attack, including fatal heart attacks, or had to go through another medical intervention. That is double the rate seen in patients with metal stents.

After the stents were taken off the market, the team decided to try to figure out if there were any warning signs that could have been detected earlier. To do this, they used Raman spectroscopy to analyze the microstructure of the stents. This technique, which uses light to measure energy shifts in molecular vibrations, offers detailed information about the chemical composition of a material. Ferralis and Grossman modified and optimized the technique for studying stents.

The researchers found that at the microscopic level, polymer stents have a heterogeneous structure that eventually leads to structural collapse. While the outer layers of the stent have a smooth crystalline structure made of highly aligned polymers, the inner core tends to have a less ordered structure. When the stent is inflated, these regions are disrupted, potentially causing early loss of integrity in parts of the structure.

“Because the nonuniform degradation will cause certain locations to degrade faster, it will promote large deformations, potentially causing flow disruption,” Wang says.

When the stents become deformed, they can block blood flow, leading to clotting and potentially heart attacks. The researchers believe that the information they gained in this study could help stent designers come up with alternative approaches to fabricating stents, allowing them to possibly eliminate some of the structural irregularities.

A silent problem

Another reason that these problems weren’t detected earlier, according to the researchers, is that many preclinical tests were conducted for only about six months. During this time, the polymer devices were beginning to degrade at the microscopic level, but these flaws couldn’t be detected with the tools scientists were using to analyze them. Visible deformations did not appear until much later.

“In this period of time, they don’t visibly erode. The problem is silent,” Edelman says. “But by the end of three years, there’s a huge problem.”

The researchers believe that their new method for analyzing the device’s microstructure could help scientists better evaluate new stents as well as other types of degradable polymer devices.

“This method provides a tool that allows you to look at a metric that very early on tells you something about what will happen much later,” Edelman says. “If you know about potential issues in advance, you can have a better idea of where to look in animal models and clinical models for safety issues.”back to newsletter

The research was funded by Boston Scientific Corporation and the National Institutes of Health.

Anne Trafton | MIT News Office
February 26, 2018

Research shows that, contrary to accepted rule of thumb, a 10- or 15-year lifetime can be good enough.
MIT Solar Cell Durability
A new study shows that replacing new solar panels after just 10 or 15 years, using the existing mountings and control systems, can make economic sense, contrary to industry expectations that a 25-year lifetime is necessary.

A new study shows that, contrary to widespread belief within the solar power industry, new kinds of solar cells and panels don’t necessarily have to last for 25 to 30 years in order to be economically viable in today’s market.

Rather, solar panels with initial lifetimes of as little as 10 years can sometimes make economic sense, even for grid-scale installations — thus potentially opening the door to promising new solar photovoltaic technologies that have been considered insufficiently durable for widespread use.

The new findings are described in a paper in the journal Joule, by Joel Jean, a former MIT postdoc and CEO of startup company Swift Solar; Vladimir Bulović, professor of electrical engineering and computer science and director of MIT.nano; and Michael Woodhouse of the National Renewable Energy Laboratory (NREL) in Colorado.

“When you talk to people in the solar field, they say any new solar panel has to last 25 years,” Jean says. “If someone comes up with a new technology with a 10-year lifetime, no one is going to look at it. That’s considered common knowledge in the field, and it’s kind of crippling.”

Jean adds that “that’s a huge barrier, because you can’t prove a 25-year lifetime in a year or two, or even 10.” That presumption, he says, has left many promising new technologies stuck on the sidelines, as conventional crystalline silicon technologies overwhelmingly dominate the commercial solar marketplace. But, the researchers found, that does not need to be the case.

“We have to remember that ultimately what people care about is not the cost of the panel; it’s the levelized cost of electricity,” he says. In other words, it’s the actual cost per kilowatt-hour delivered over the system’s useful lifetime, including the cost of the panels, inverters, racking, wiring, land, installation labor, permitting, grid interconnection, and other system components, along with ongoing maintenance costs.

Part of the reason that the economics of the solar industry look different today than in the past is that the cost of the panels (also known as modules) has plummeted so far that now, the “balance of system” costs — that is, everything except the panels themselves —  exceeds that of the panels. That means that, as long as newer solar panels are electrically and physically compatible with the racking and electrical systems, it can make economic sense to replace the panels with newer, better ones as they become available, while reusing the rest of the system.

“Most of the technology is in the panel, but most of the cost is in the system,” Jean says. “Instead of having a system where you install it and then replace everything after 30 years, what if you replace the panels earlier and leave everything else the same? One of the reasons that might work economically is if you’re replacing them with more efficient panels,” which is likely to be the case as a wide variety of more efficient and lower-cost technologies are being explored around the world.

He says that what the team found in their analysis is that “with some caveats about financing, you can, in theory, get to a competitive cost, because your new panels are getting better, with a lifetime as short as 15 or even 10 years.”

Although the costs of solar cells have come down year by year, Bulović says, “the expectation that one had to demonstrate a 25-year lifetime for any new solar panel technology has stayed as a tautology. In this study we show that as the solar panels get less expensive and more efficient, the cost balance significantly changes.”

He says that one aim of the new paper is to alert the researchers that their new solar inventions can be cost-effective even if relatively short lived, and hence may be adopted and deployed more rapidly than expected. At the same time, he says, investors should know that they stand to make bigger profits by opting for efficient solar technologies that may not have been proven to last as long, knowing that periodically the panels can be replaced by newer, more efficient ones. 

“Historical trends show that solar panel technology keeps getting more efficient year after year, and these improvements are bound to continue for years to come,” says Bulović. Perovskite-based solar cells, for example, when first developed less than a decade ago, had efficiencies of only a few percent. But recently their record performance exceeded 25 percent efficiency, compared to 27 percent for the record silicon cell and about 20 percent for today’s standard silicon modules, according to Bulović. Importantly, in novel device designs, a perovskite solar cell can be stacked on top of another perovskite, silicon, or thin-film cell, to raise the maximum achievable efficiency limit to over 40 percent, which is well above the 30 percent fundamental limit of today’s silicon solar technologies. But perovskites have issues with longevity of operation and have not yet been shown to be able to come close to meeting the 25-year standard.

Bulović hopes the study will “shift the paradigm of what has been accepted as a global truth.” Up to now, he says, “many promising technologies never even got a start, because the bar is set too high” on the need for durability.

For their analysis, the team looked at three different kinds of solar installations: a typical 6-kilowatt residential system, a 200-kilowatt commercial system, and a large 100-megawatt utility-scale system with solar tracking. They used NREL benchmark parameters for U.S. solar systems and a variety of assumptions about future progress in solar technology development, financing, and the disposal of the initial panels after replacement, including recycling of the used modules. The models were validated using four independent tools for calculating the levelized cost of electricity (LCOE), a standard metric for comparing the economic viability of different sources of electricity.

In all three installation types, they found, depending on the particulars of local conditions, replacement with new modules after 10 to 15 years could in many cases provide economic advantages while maintaining the many environmental and emissions-reduction benefits of solar power. The basic requirement for cost-competitiveness is that any new solar technology that is to be installed in the U.S should start with a module efficiency of at least 20 percent, a cost of no more than 30 cents per watt, and a lifetime of at least 10 years, with the potential to improve on all three.

Jean points out that the solar technologies that are considered standard today, mostly silicon-based but also thin-film variants such as cadmium telluride, “were not very stable in the early years. The reason they last 25 to 30 years today is that they have been developed for many decades.” The new analysis may now open the door for some of the promising newer technologies to be deployed at sufficient scale to build up similar levels of experience and improvement over time and to make an impact on climate change earlier than they could without module replacement, he says.

“This could enable us to launch ideas that would have died on the vine” because of the perception that greater longevity was essential, Bulović says.back to newsletter

The study was supported by the Tata-MIT GridEdge Solar research program.

– David L. Chandler | MIT News Office 
September 19, 2019

Friday, 22 June 2018 14:16

Summer projects in motion

Lab assignments for MIT Materials Research Laboratory undergraduate researchers and  teachers cut across disciplines.

From simulating the physics of spinning magnetic particles to fabricating new materials for infrared chemical sensing, MIT Materials Research Laboratory summer researchers will challenge themselves to learn new skills and develop new scientific insights.

A diverse group of top-performing undergraduates from across the U.S. and Puerto Rico as well as local community college students and teachers, these interns will spend the summer doing research in MIT faculty labs with support from the National Science Foundation’s Research Experience for Undergraduates (REU) and Research Experience for Teachers (RET) programs, NSF CAREER award, the AIM Photonics Academy and the MRL Collegium.

Community College students and teachers were assigned their lab placements, but the group of 12 Summer Scholars chose their lab placements after hearing presentations from 19 faculty members and touring their labs over three days. MIT Professors and Research Scientists participating in the presentations come from the departments of materials science and engineering, mechanical engineering, civil and environmental engineering, electrical engineering and computer science, aeronautics and astronautics, biological engineering, chemical engineering, chemistry, and physics.

Associate Professor of Materials Science and Engineering Alfredo Alexander-Katz is leading a summer project with potential to apply machine learning to the game-like motion of magnetic particles spinning in a neutral-particle medium and discovering how they form crystal shapes. “Programming is a great experience,” Alexander-Katz says. Oregon State University rising senior physics major Ryan Tollefsen, who will work with Alexander-Katz, expressed his interest immediately after a lab tour. “I’ve been coding physics simulations in Python for the last year and a half,” Tollefsen says. “It’s definitely my favorite I’ve seen out of everything so far,” he says.

Sarai Patterson, a University of Utah materials science and engineering major, chose to work in the lab of ARCO Career Development Professor William A. Tisdale, where she’ll tackle a project to study halide perovskite nanocrystals for energy conversion. “I worked in a characterization lab for two years at school, but this is different types of characterization that I’ve never done before with the laser lab and optical properties. So I’m really excited about the characterization of these nanocrystals,” Patterson says.

Associate Professor of Materials Science and Engineering Juejun (JJ) Hu is developing new materials for nonlinear integrated photonics based on the chalcogen elements of silicon, selenium and tellurium. These materials, known as chalcogenide glasses, can be used for infrared sensing and imaging. Alvin Chang, an Oregon State University Biological Engineering major, with a minor in Entrepreneurship, says, “I was kind of drawn to that because I wanted to seek a project that was sort of related to my work at my home institution but also branching off. … I’ve worked with optics before, so I kind of know how it goes, but this is the first time I’ve heard about nonlinear photonics. So I thought that was a very interesting field to study.”

Bruce Quinn, from Roxbury Community College, will intern in Assistant Professor of Materials Science and Engineering Rafael Jaramillo’s lab through the new Guided Academic Industry Network (GAIN) program, which is funded through Jamarillo’s National Science Foundation CAREER award. Jaramillo’s lab is developing new electronic materials from special compounds known as complex chalcogenides.

The summer researchers will present their results at a Poster Session on Wednesday, Aug. 8, 2018.

Intern MIT Placement Home Institution
Astatke Assaminew Katharina Ribbeck Roxbury Community College
Danielle Beatty Elsa Olivetti University of Utah
Alvin Chang Juejun [JJ] Hu Oregon State University
Simon Egner Dr. Anu Agarwal University of Illinois at Urbana-Champaign 
Zhirong Fan Fikile Brushett​ Bunker Hill Community College
Heather Giblin Katharina Ribbeck Brookline High School, Biology teacher​
Elizabeth [Lily] Hallett Karl Berggren University of Arkansas, Fayetteville
Juan Hincapie Riccardo Comin Roxbury Community College
Credoritch Joseph Rob Macfarlane Roxbury Community College 
Julianna La Lane Fikile Brushett University of Puerto Rico at Mayaguez
Minhua Mei Dr. Mehmet Kanik Bunker Hill Community College
Michael Molinski Rafael Jaramillo

University of Rhode Island

Wendy Moy Riccardo Comin Diamond Middle School, Physical Science teacher, Lexington
Abigail Nason​ Brian Wardle University of Florida​
Fernando Nieves Munoz Krystyn Van Vliet University of Puerto Rico at Mayaguez
Sarai Patterson William Tisdale University of Utah
Bruce Quinn Rafael Jaramillo Roxbury Community College
Sabrina Shen Markus Buehler Johns Hopkins University
Kimberly Stieglitz Rob Macfarlane Roxbury Community College, Chemistry and Biotechnology Professor
Ryan Tollefsen Alfredo Alexander-Katz Oregon State University
Ekaterina [Stella] Tsotsos Caroline Ross Brown University

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Denis Paiste, MIT Materials Research Laboratory
June 25, 2018

Wednesday, 16 January 2019 15:50

Summer Scholar Update: Bart Machielse

Bart Machielse CloseUp 0192 Web
Summer Scholar Bart Machielse examines a tellurium thin film coated onto a silicon oxide on silicon base in a glovebox during his 2015 NSF REU in the lab of MIT Assistant Professor Juejun (JJ) Hu, working on an infrared photonics project. Photo, Denis Paiste, MIT Materials Research Laboratory.

What graduate program are you currently pursuing?

I'm pursuing a PhD in physics at Harvard in the Lukin and Loncar groups. I do research on nanophotonics and quantum emitters in diamond with applications in quantum networks.


Feb. 15, 2019 

This year's Summer Scholar Internship Program runs June 16 to Aug. 10, 2019.

  Learn more 


What awards have you received?

I received a National Science Foundation Graduate Research Fellowship in 2016, which is funding the first three years of my research.

What about your MIT Summer Scholar experience was most enjoyable?

MIT Summer school offered the best summer-long research experience I could have imagined. In three months, I got to work on three very different projects that taught me skills and knowledge that I continue to use today. Professor Juejun (JJ) Hu's group worked really hard to integrate me into its work, making me a part of the team despite the short time I was there.

How did your MIT Summer Scholars experience contribute to getting you where you are today?

Conducting research outside my home institution as an undergraduate taught me a lot about how different institutions are organized and helped me figure out what I wanted out of a community and research team.

Bart Machielse January 2019 SQ Web

The specific skills and knowledge I learned I still use almost every day, especially with regards to nanophotonics and nanofabrication.

What are your future plans or ambitions?

Continue to do research on quantum networks in an academic or industrial setting.

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Watch a video of Bart Machielse’s 2015 summer internship.

Watch videos of 2018 MIT MRL Summer Scholars.

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