Apr 30

As previously announced, beginning July 1, 2018, our institutional proposal submission process will transition from COEUS to the new Grants module in myResearch. myResearch Grants is on target to go live May 15, 2018. Since COEUS will cease operation after June 30th, it is imperative that PIs and administrative staff be mindful of this transition and how it may affect sponsor deadlines. Therefore, proposal preparation and submission must be planned accordingly.

In order to provide the Office of Sponsored Programs with sufficient time to transition, all COEUS applications should be submitted by June 22nd at the latest. COEUS will no longer be accessible to the campus on July 1st, so it is strongly recommended that any important information currently stored in COEUS be downloaded and stored elsewhere.

Training for myResearch Grants will begin May 4th. The training sessions will cover the myResearch Grants proposal and endorsement process, including funding proposals, budget preparation, and credit split. Classrooms have been held for in-person training in both East and West Campus locations.

The link to register is:

In addition to the in-person training, the Office of Sponsored Programs is offering the opportunity to attend two livestream sessions of the myResearch Grants training.

When: Monday, May 7th from 9-11am AND Wednesday, May 9th from 9-11am

How to access the livestream session: Click the following link: myResearch Grants Training - Livestream:

For any questions or comments related to myResearch Grants, please email us at:

Mar 15

Figuring out what is true in science when researchers are bombarded with information from many different studies is a challenge. A new paper, published in Nature, reveals that the power of meta-analysis in research synthesis over the past 40 years has transformed scientific thinking and research approaches. Meta-analysis has also become invaluable to making advances in many scientific fields, including medicine and ecology.


Meta-analysis is the quantitative, scientific synthesis of research results from different studies investigating the same question. Since the approach (and the term) were first introduced in the 1970s, meta-analysis has been used to resolve seemingly contradictory research outcomes, to identify where more research is needed, and to tell scientists when no more studies are needed because the answers have become clear.

“Meta-analysis is the grandmother of Big Data and Open Science. Our paper illustrates how meta-analysis is used in different scientific fields, why it has become so important, and what criticisms and limitations it faces,” said co-author Jessica Gurevitch, PhD, Professor of Ecology & Evolution as Stony Brook University. “It is a statistical and scientific approach to resolving questions and reaching generalizations, but it is not magic, and can’t produce data on its own where none exists.”

In the paper “Meta-analysis and the science of research synthesis,” Professor Gurevitch and colleagues from the University of New South Wales in Australia and Newcastle University and Royal Holloway in the United Kingdom review research over the 40 years to illustrate the accomplishments and challenges of the method, along with new advances and direction of meta-analysis in 21st Century scientific research.

Even when trying to discover things that have been the subject of many experiments, such as whether boys or girls are better at math or the best treatment immediately after a stroke, Professor Gurevitch explains, the use of meta-analysis is essential to reduce biases and strengthen methods to determine the answer, or answers.

“By bringing the scientific method into the synthesis of results across independent studies, we can ask—and answer—questions we could never hope to resolve before, while new methods in meta-analysis open doors to the resolution of seemingly intractable problems,” adds Shinichi Nakagawa, a co-author from the University of New South Wales.

Citing some of the examples of what recent advances in meta-analysis have taught us, Professor Gurevitch explains that by combining experiments in a rigorous manner, “In medicine, we have been able to compare the effectiveness of treatments that have never been directly compared in any one study, and we can save lives by understanding what works long before it is apparent in any single experiment.

“In ecology and evolutionary biology, we can evaluate patterns across wide expanses of space and a diversity of animals and plants that are more than any one researcher could study in several lifetimes. In conservation, we may find out what measures really work best to achieve the goals of preserving biodiversity and threatened ecosystems. “

For more about the impact about the study findings on scientific research, read Professor Gurevitch’s blog post.

Mar 22

New York’s U.S. Congressman Lee Zeldin has received the National Sea Grant Award from the National Oceanic and Atmospheric Administration’s National Sea Grant Program for his continued support of this national coastal science association. New York Sea Grant Director and SBU Professor Bill Wise presented the award to him in Washington, DC, on March 7 along with SGA President Jim Hurley. New York Sea Grant is headquartered at Stony Brook University.

New York Sea Grant (NYSG) is a statewide network of integrated research, education and extension services promoting coastal community economic vitality, environmental sustainability and citizen awareness about the state’s marine and Great Lake resources. Last year when federal funding for the non-profit Sea Grant program was eliminated from the budget, Congressman Zeldin was instrumental in securing full funding of $72.5 million for the program through a bipartisan appropriations request. He continued to fight during this year’s budget so that such critical funding will continue to be provided. In addition, he secured more than 100K in funding for NYSG to support the seafood and aquaculture industry and to foster relationships between the industry and next generation of fishermen and other seafood professionals.

“Representing a district almost completely surrounded by saltwater, funding to support our fishermen, our oyster growers, protect our beaches, and support marine science research is essential for our local economy and environment,” said Congressman Zeldin. “The Sea Grant Association plays a critical role in securing and providing this funding to the Long Islanders who rely on it most, and it is such an honor to receive this award from such a worthwhile organization.”

“New York Sea Grant and the coastal residents, businesses and communities our program serves are thankful for Congressman Zeldin’s support,” said NYSG Director Bill Wise. “This national network has existed for over 50 years thanks to Congressional budget support like this.”

Each year NYSG supports millions in university-based research related to a variety of marine, Hudson estuary, and Great Lakes topics and issues. Results and resources from these investigations —conducted by top-notch physical oceanographers, food scientists, benthic ecologists, aquatic toxicologists, fisheries modelers, geochemists, and others — provide useful information to the public, businesses, and managers. Sea Grant research also sets benchmarks within the scientific community, advancing the state of knowledge in many fields.

To learn more about New York Sea Grant, please visit

Mar 29

People have become familiar with “bomb cyclones” this winter, as several powerful winter storms brought strong winds and heavy precipitation to the U.S. east coast, knocking out power and causing flooding. With strength that can rival that of hurricanes, bomb cyclones get their name from a process called bombogenesis, which describes the rapid intensification they undergo within 24 hours as they move along the coast.

These winter storms tend to form and travel within narrow “atmospheric conveyor belts”, called storm tracks, which can change location over a period of years.

Scientists have extensively studied potential causes behind these year-to-year changes in attempt to better forecast storm tracks and their extreme impacts, but new research from scientists at the Stony Brook University (SBU) School of Marine and Atmospheric Sciences, funded by NOAA Research’s MAPP Program, identifies another crucial controlling force.

After analyzing 38 years of model data, the research team found that an alternating pattern of winds high up in the tropical stratosphere, called the Quasi-Biennial Oscillation (QBO), affects significant year-to-year changes in both the North Pacific and North Atlantic storm tracks.

The QBO’s dual influence
Past research has primarily considered how variabilities in the lower part of our atmosphere — the troposphere — and in the polar region of our stratosphere influence storm tracks. These studies mostly found that different atmospheric patterns affected storm tracks in just one ocean basin. For instance, the El Niño-Southern Oscillation influences the North Pacific storm track but not the North Atlantic storm track.

“This study finds that the QBO modulates the North Pacific and North Atlantic storm track simultaneously. Such a finding on a basin-wide influence is relatively new,” said Hyemi Kim, paper co-author and SBU Assistant Professor.

Not only does the QBO influence both the North Pacific and North Atlantic storm tracks, but the authors also found that the two storm tracks respond differently.

“When the QBO pattern has easterly winds, the North Pacific storm track shifts further north, while the North Atlantic storm track shifts to a lower vertical height in the atmosphere,” said Jiabao Wang, graduate researcher and lead author of the paper.

In addition, when the QBO pattern has westerly winds, the North Atlantic storm track shifts to a higher vertical height in the atmosphere. The authors explained that these directional and vertical shifts in storm track locations can cause changes in local weather and climate, such as strong winds and heavy precipitation, and can impact aviation by causing severe turbulence in higher or lower parts of the atmosphere.

“Because the QBO is a fairly uniform circumglobal phenomenon, we thought that its influence on storm tracks over the two basins would be similar,” said Wang. “The different responses between the North Pacific and North Atlantic storm track to the QBO were not as expected.”

Given that the QBO’s alternating pattern every 2-3 years can be accurately predicted up to 12 months in advance, Edmund Chang, co-author and SBU Professor, explained that these storm track changes and, potentially, the likelihood of related natural disasters should be predictable out to several months ahead of time. Thus, their study offers a new pathway to improve seasonal forecasts of storm tracks and their extreme impacts — like future winter weather bombs.

If forecasters take the QBO into account, Chang noted that the potential prediction improvements would provide useful information to advance decision-making in many sectors, including wind and solar energy, agriculture, water management, and emergency response.

View the paper:

Wang, J., Kim, H.-M. & Chang, E. K. M. (2018). Interannual Modulation of Northern Hemisphere Winter Storm Tracks by the QBO. Geophysical Research Letters, 45.

— Ali Stevens

Mar 29

Professor Robert Patro of the Department of Computer Science has received a 2018 National Science Foundation (NSF) CAREER award for his research proposal, A Comprehensive and Lightweight Framework for Transcriptome Analysis.

In layman’s terms, this project focuses on the field of RNA (ribonucleic acid) research and how to analyze sequencing data pertaining to it. In addition to performing various other functions in the cell, RNA acts as a messenger molecule, carrying instructions from DNA and acting as a template for protein synthesis.

“As a researcher at an institution focused on developing engineering-driven solutions in medical research, his proposed project supports not only the mission of the Department of Computer Science but also the University as a whole,” said Samir Das, chair of computer science at Stony Brook.

As Patro’s project proposal explains, the goal is “to develop a new generation of accurate, lightweight methods for the analysis of both bulk and single-cell transcriptomic data.” Patro says the project should “push forward the state-of-the-art in terms of both the accuracy and fundamental capabilities of lightweight transcriptome analysis methods.” He hopes the final outcome of the project will provide a new generation of accurate and lightweight transcriptome analysis tools and methods. These advancements in method and software should ultimately reduce costs, enable new analyses, and help contribute to discoveries in future RNA research.

The NSF CAREER funding in the amount of $625,000 supports Patro’s involvement as well as that of several grad and PhD students working in his research lab. The education plan detailed in the CAREER proposal involves working with both students and the campus community and incorporates creating a series of educationally-driven podcasts and videos. He believes that in using a variety of educational methods to accompany his CAREER research he will reach people of both technical and non-technical backgrounds as well as people from diverse communities. In conjunction, Professor Patro also has the support of Stony Brook’s Alan Alda Center for Communicating Science.

Robert Patro is an assistant professor of computer science in the College of Engineering and Applied Sciences at Stony Brook University since 2014. He earned a PhD and BS in computer science from the University of Maryland-College Park. Prior to joining Stony Brook, he was a visiting scholar as well as a Postdoctoral Research Associate at Carnegie Mellon University. Patro’s main academic interests are in the design of algorithms and data structures for processing, organizing, indexing and querying high-throughput genomics data. He is also interested in the intersection between efficient algorithms and statistical inference. Previous to this NSF CAREER award, Patro was the Stony Brook PI on an NSF award shared with Cambridge University entitled Data-driven hierarchical analysis of de novo transcriptomes. Patro and his students develop, maintain and contribute to a number of different open-source bioinformatics software tools.

Jan 09

Suffolk County reportedly has recorded the most car accidents caused by sleepy drivers in the state; Stony Brook University researchers are on a mission to help turn that around.

Drowsy driving is a threat to safety.

The School of Health Technology & Management (SHTM) was recently awarded a General Highway Safety Grant to conduct research to put together insights, methods of prevention and a program to combat drowsy driving among college students.

The research project timeline runs from October of last year through September 2018 and will involve data collection on sleep habits and drowsy driving behaviors among Stony Brook commuter students, the development of a research-informed Drowsy Driving Prevention curriculum, a pilot implementation, and an external program evaluation.

“It is a myth that rolling down the windows and turning up the radio volume is a way to stay awake,” said Prof. Russell Rozensky, director of the Polysomnographic Technology Program (PTP) which is conducting the research as part of the SHTM. PTP consists of polysomnographic technologists that are health care practitioners who use “high-tech” equipment to diagnose and treat patients with sleep disorders.

According to stats compiled by the National Sleep Foundation, adults ages 18-29 are more likely to say they’ve driven drowsy (71 percent), compared to adults ages 30-64. The National Sleep Foundation estimated that younger drivers account for almost two-thirds of drowsy-driving crashes. A report conducted by, a website developed by the New York State Governor’s Traffic Safety Committee that shares information about traffic safety and the state’s highway safety grant program, states that Suffolk County has the highest incidence of drowsy driving related crashes in all New York.

But the problem is not confined to New York. An estimated 6,000 fatal crashes nationwide each year are caused by people falling asleep at the wheel, according to the SHTM website.

The program and website were developed by the SHTM’s Drowsy Driving Prevention team in collaboration with the Governors Highway Safety Association and funded by the Governor’s Traffic Safety Committee and the National Road Safety Foundation. The educational and interactive website includes a sleepiness assessment quiz to help users realize their own risk for drowsy driving, facts and myths about the problem and strategies to help improve sleep habits to reduce incidence of falling asleep at the wheel and crashes associated with that.

The Drowsy Driving project is housed within the SHTM’s Center for Community Engagement and Leadership and includes Rozensky, Principal Investigator Lisa M. Endee, co-principal investigators Erik Flynn, Pamela LindenStephen G. Smith, and Project Research Assistant Anna Lubitz.

“Most people would never consider driving when drunk, yet would not think twice about getting behind the wheel when sleepy,” said Endee, who serves as clinical assistant professor of the Polysomnographic Technology Program. “Driving while sleep deprived can be as dangerous as driving under the influence of alcohol or drugs. It is this important message that our Drowsy Driving Prevention team hopes to bring awareness to.”
SHTM’s drowsy driving team offered these 5 tips to avoid drowsy driving:

  1. Take Power Naps on the Road: If you find yourself drowsy while driving you should pull over to take a 30-minute power nap, according to Professor Russell Rozensky.
  2. Make Regular Pit Stops: Get out of the car to every 90 minutes or so to stretch, as it increases the alertness level and helps prevent fatigued muscles.
  3. Avoid Driving in Early Morning Hours: Do not drive between midnight and 6 a.m. Because of your body’s biological rhythm, this is a time when you will feel the most powerful need for sleep, Rozensky said.
  4. Drink Lots of Coffee or Caffeinated Beverages: Drinking caffeine or other caffeinated beverages helps with alertness. A caffeine buzz can last up to six hours, Rozensky said. Rozensky added that drinking coffee on car rides also may cause drivers and passengers to pull over frequently to make bathroom trips. This, in turn, allows them to stretch, keeping them awake and alert, he said.
  5. Use the Buddy System: Having somebody to interact with while driving keeps you awake and alert to your surroundings, according to Rozensky. “The passenger can evaluate the driver to see if the driver is showing signs and symptoms of drowsy driving such as yawning, difficulty focusing, heavy eyelids, frequent blinking, or zoning out,” he said.

For more tips and information on how to combat drowsy driving, visit

— Suzanne Mobyed

Sep 07

Despite centuries of studying the atom and the particles within it, the mysteries of matter continue to elude scientists. What are we really made of?

An Electron-Ion Collider would probe the inner microcosm of protons to help scientists understand how interactions among quarks (colored spheres) and glue-like gluons (yellow) generate the proton’s essential properties and the large-scale structure of the visible matter in the universe today.
To solve such an enigma and better understand the building blocks of our universe, Stony Brook University and the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory (BNL) have partnered to establish the Center for Frontiers of Nuclear Science, bolstered by a new $5 million grant from the Simons Foundation.

“The Center for Frontiers in Nuclear Science will bring us closer to understanding our universe in ways in which it has never before been possible,” said Samuel L. Stanley Jr., MD, President of Stony Brook University. “Thanks to the vision of the Simons Foundation, scientists from Stony Brook, Brookhaven Laboratory and many other institutions are now empowered to pursue the big ideas that will lead to new knowledge about the structure of everything in the universe today.”

Establishing the Center is a big step toward discovering the unknown essentials of matter for Stony Brook and BNL, which already have internationally renowned programs in nuclear physics. But before solving such a mystery, one must first know the clues. Here’s a quick breakdown.

Matter is any substance that has mass and takes up space. An atom is the smallest unit of matter. At an atom’s core is its nucleus, made of protons of neutrons — subatomic particles collectively called nucleons. Looking deeper, nucleons are made of elementary particles called quarks and gluons, and this is where the trail goes cold.

“The role of quarks and gluons in determining the properties of protons and neutrons remains one of the greatest unsolved mysteries in physics,” said Doon Gibbs, Ph.D., Brookhaven Lab Director.

Solving this mystery is the focus of quantum chromodynamics (QCD), a branch of theoretical physics that investigates how quarks and gluons interact as fundamental elements of matter.

Stony Brook and BNL’s new center is slated to become a leading international research and educational hub for QCD over the next several decades, uniting our faculty, students and researchers with BNL staff and scientists from around the world in an effort to crack the quantum case.

One key aspect of the Center’s launch is a proposed Electron Ion Collider (EIC), a powerful new particle accelerator that would create rapid-fire, high-resolution “snapshots” of quarks and gluons contained in nucleons and complex nuclei — crucial to QCD progress.

Abhay Deshpande, PhD, Professor of experimental nuclear physics in the Department of Physics and Astronomy in the College of Arts and Sciences at Stony Brook University
“An Electron Ion Collider would reveal the internal structure of these atomic building blocks, a key part of the quest to understand the matter we’re made of,” Gibbs said.

Abhay Deshpande, professor of experimental nuclear physics in the Department of Physics and Astronomy, has been named Director of the Center, as well as Director of Electron Ion Collider Science at BNL.

A champion of the EIC for decades, Deshpande is positioned to lead development of the collider, which was deemed highest priority for new facility construction by the National Science Foundation’s Nuclear Science Advisory Committee in an effort to strengthen and expand U.S. leadership in nuclear physics and stimulate economic benefits well into the 2040s.

Like most mysteries, collaboration is the key to success, so Deshpande is focused on uniting QCD and EIC experts from around the globe with Stony Brook students who will serve as the next generation of researchers in the field.

“Overall, I want the worldwide community of EIC enthusiasts to see the Center for Frontiers in Nuclear Science as their ‘home away from home,’ where they can come and work on EIC-related research,” Deshpande said. “My hope is that within a short time, the students at Stony Brook will have more opportunities to work with researchers at Brookhaven, and vice-versa.”

Despite the complexity of nuclear physics and related areas of study, the results of such research could reveal the most basic aspects of our very existence.

“Nuclear physics is a deep and important discipline, casting light on many poorly understood facets of matter in our universe,” said Jim Simons, chairman of the Simons Foundation. “It is a pleasure to support research in this area conducted by members of the outstanding team to be assembled by Brookhaven Lab and Stony Brook University.”

Through major funding, the Simons Foundation is bonding a partnership between Stony Brook and BNL perhaps as strong as the interaction between quarks and gluons.

“Basic science research seeks to improve our understanding of the world around us, and it can take human understanding to wonderful and unexpected places,” said Marilyn Simons, president of the Simons Foundation. “Exploring the qualities and behaviors of fundamental particles seems likely to do just that.”

— By Brian Smith

Sep 07

Scientists have yet to understand and explain how life’s informational molecules – proteins and DNA and RNA – arose from simpler chemicals when life on earth emerged some four billion years agoScientists have yet to understand and explain how life’s informational molecules – proteins and DNA and RNA – arose from simpler chemicals when life on earth emerged some four billion years ago. Now a research team from the Stony Brook University Laufer Center for Physical and Quantitative Biology and the Lawrence Berkeley National Laboratory believe they have the answer. They developed a computational model explaining how certain molecules fold and bind together to grow longer and more complex, leading from simple chemicals to primitive biological molecules. The findings are reported early online in PNAS.

Ken Dill
Ken Dill explains the computational model that shows how certain molecules fold and bind together in the evolution of chemistry into biology, a key step to explain the origins of life.
Previously scientists learned that the early earth likely contained the basic chemical building blocks, and sustained spontaneous chemical reactions that could string together short chains of chemical units. But it has remained a mystery what actions could then prompt short chemical polymer chains to develop into much longer chains that can encode useful protein information. The new computational model may help explain that gap in the evolution of chemistry into biology.

“We created a computational model that illustrates a fold-and-catalyze mechanism that amplifies polymer sequences and leads to runaway improvements in the polymers,” said Ken Dill, lead author, Distinguished Professor and Director of the Laufer Center. “The theoretical study helps to understand a missing link in the evolution of chemistry into biology and how a population of molecular building blocks could, over time, result in the emergence of catalytic sequences essential to biological life.”

In the paper, titled “The Foldamer Hypothesis for the growth and sequence-differentiation of prebiotic polymers,” the researchers used computer simulations to study how random sequences of water-loving, or polar, and water-averse, or hydrophobic, polymers fold and bind together. They found these random sequence chains of both types of polymers can collapse and fold into specific compact conformations that expose hydrophobic surfaces, thus serving as catalysts for elongating other polymers. These particular polymer chains, referred to as “foldamer” catalysts, can work together in pairs to grow longer and develop more informational sequences.

This process, according to the authors, provides a basis to explain how random chemical processes could have resulted in protein-like precursors to biological life. It gives a testable hypothesis about early prebiotic polymers and their evolution.

“By showing how prebiotic polymers could have become informational ‘foldamers’, we hope to have revealed a key step to understanding just how life started to form on earth billions of years ago,” explained Professor Dill.

Co-authors of the paper include Elizaveta Guseva of the Laufer Center and Departments of Chemistry and Physics & Astronomy at Stony Brook University, and Ronald N. Zuckermann of the Lawrence Berkeley National Laboratory in Berkeley, Calif.

The research was supported in part by the National Science Foundation.

Aug 25

The U.S. has a population of more than 50 million seniors for the first time in history. As that number climbs, Stony Brook University has received a three-year $1 million grant from the W.M. Keck Foundation to fund research that uses brain imaging data to understand how the nutrition of brain neurons affects cognition in aging humans. The research could provide a critical first step toward personalized medicine in neurology for aging patients.

This collaborative project is led by Associate Professor Lilianne R. Mujica-Parodi.
The project, “Protecting the Aging Brain: Self-Organizing Networks and Multi-Scale Dynamics Under Energy Constraints,” is led by Lilianne R. Mujica-Parodi, Associate Professor of Biomedical Engineering at Stony Brook University School of Medicine. The work involves interdisciplinary research and collaboration between Stony Brook University and the Martinos Center for Biomedical Imaging at Harvard Medical School and Massachusetts General Hospital.

“This prestigious grant from the Keck Foundation supports innovative imaging research that will help transform the way scientists study the aging brain,” said Stony Brook University President Samuel L. Stanley Jr. “The funding also comes at a crucial time, as the aging of America will continue and the importance of dietary and other interventions to protect the aging brain are more vital than ever.”

Dr. Mujica-Parodi and co-investigators will integrate human neuroimaging data – from 7-Tesla fMRI and positron emission tomography – with multi-scale biomimetic modeling to test hypotheses with respect to how energy constraints based on diet and mitochondria affect neural efficiency in the aging brain.

“The collaborative work of Stony Brook faculty on the aging brain with scientists from other leading medical research institutions provides a strong basis for advancing this important area of 21st-century medicine,” said Kenneth Kaushansky, Senior Vice President for the Health Sciences and Dean of the School of Medicine. “Using extremely sophisticated imaging algorithms to trace neural pathways, coupled to metabolic interventions seen under stress, Dr. Mujica-Parodi will likely gain practical insights into methods to improve cognition in elderly individuals.”

The research builds on the pilot work of Mujica-Parodi and colleagues at Stony Brook University’s Laufer Center for Physical and Quantitative Biology and the Martinos Center for Biomedical Imaging. The team approaches brain network connectivity, assessed by fMRI and associated cognitive function, as a dynamic emergent phenomenon. They developed a metabolic-neuron hybrid model that can be used in the imaging research to identify and gauge energy input via glucose, glycogen and ketone kinetics.

“By using the imaging and biomimetic modeling techniques, we will investigate the use of exogenous ketones, a fuel source that is an alternative to glucose, as a way to ameliorate age-related effects,” explained Mujica-Parodi. “We hope our findings prove that personalized medicine for neurology is within our reach and that our methods can be a model toward that goal.”

The research team will use their approach to predict how neural networks self-organize in response to changes in energy supply and demand, and then compare those results to data on individuals to better understand the exact connection between nutrition to brain neurons and cognitive capacity.

Aug 25

Researchers from Stony Brook University, Brookhaven National Laboratory and the Hebrew University of Jerusalem have discovered new effects of an important method for modulating semiconductors.


The method, which works by creating open spaces or “vacancies” in a material’s structure, enables scientists to tune the electronic properties of semiconductor nanocrystals (SCNCs) — semiconductor particles that are smaller than 100 nanometers. This finding will advance the development of new technologies like smart windows, which can change opaqueness on demand.

Anatoly Frenkel, a professor in Stony Brook’s Department of Materials Science and Chemical Engineering in the College of Engineering and Applied Sciences, holds a joint appointment at Brookhaven National Laboratory and was the lead BNL researcher on this study.

Scientists use a technique called “chemical doping” to control the electronic properties of semiconductors. In this process, chemical impurities — atoms from different materials — are added to a semiconductor in order to alter its electrical conductivity. Though it is possible to dope SCNCs, it is very difficult due to their tiny size. The amount of impurities added during chemical doping is so small that in order to dope a nanocrystal properly, no more than a few atoms can be added to the crystal. Nanocrystals also tend to expel impurities, further complicating the doping process.

Seeking to control the electronic properties of SCNCs more easily, researchers studied a technique called vacancy formation. In this method, impurities are not added to the semiconductor; instead, vacancies in its structure are formed by oxidation-reduction (redox) reactions, a type of chemical reaction where electrons are transferred between two materials. During this transfer, a type of doping occurs as missing electrons, called holes, become free to move throughout the structure of the crystal, significantly altering the electrical conductivity of the SCNC.

“We have also identified size effects in the efficiency of the vacancy formation doping reaction,” said Uri Banin, a nanotechnologist from the Hebrew University of Jerusalem. “Vacancy formation is actually more efficient in larger SCNCs.”

In this study, the researchers investigated a redox reaction between copper sulfide nanocrystals (the semiconductor) and iodine, a chemical introduced in order to influence the redox reaction to occur.

“If you reduce copper sulfide, you will pull out copper from the nanocrystal, generating vacancies and therefore holes,” said Frenkel.

The researchers used the x-ray powder diffraction (XPD) beamline at the National Synchrotron Light Source II (NSLS-II)—a DOE Office of Science User Facility—to study the structure of copper sulfide during the redox reaction. By shining ultra-bright x-rays onto their samples, the researchers are able to determine the amount of copper that is pulled out during the redox reaction.

Based on their observations at NSLS-II, the team confirmed that adding more iodine to the system caused more copper to be released and more vacancies to form. This established that vacancy formation is a useful technique for tuning the electronic properties of SCNCs.

Still, the researchers needed to find out what exactly was happening to copper when it left the nanocrystal. Understanding how copper behaves after the redox reaction is crucial for implementing this technique into smart window technology.

“If copper uncontrollably disappears, we can’t pull it back into the system,” Frenkel said. “But suppose the copper that is taken out of the crystal is hovering around, ready to go back in. By using the reverse process, we can put it back into the system, and we can make a device that would be easy to switch from one state to the other. For example, you would be able to change the transparency of a window on demand, depending on the time of day or your mood.”


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