PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Engineers apply physics-informed machine learning to solar cell production

Lehigh University researchers use Frontera supercomputer to simulate photovoltaic fabrication, train AI to optimize energy production

Engineers apply physics-informed machine learning to solar cell production
2021-06-09
(Press-News.org) Today, solar energy provides 2% of U.S. power. However, by 2050, renewables are predicted to be the most used energy source (surpassing petroleum and other liquids, natural gas, and coal) and solar will overtake wind as the leading source of renewable power. To reach that point, and to make solar power more affordable, solar technologies still require a number of breakthroughs. One is the ability to more efficiently transform photons of light from the Sun into useable energy.

Organic photovoltaics max out at 15% to 20% efficiency -- substantial, but a limit on solar energy's potential. Lehigh University engineer Ganesh Balasubramanian, like many others, wondered if there were ways to improve the design of solar cells to make them more efficient?

Balasubramanian, an associate professor of Mechanical Engineering and Mechanics, studies the basic physics of the materials at the heart of solar energy conversion -- the organic polymers passing electrons from molecule to molecule so they can be stored and harnessed -- as well as the manufacturing processes that produce commercial solar cells.

Architecture of the OPV bulk-heterojunction structure and the design scope. [Credit: Ganesh Balasubramanian, Joydeep Munshi, Lehigh University]

Using the Frontera supercomputer at the Texas Advanced Computing Center (TACC) -- one of the most powerful on the planet -- Balasubramanian and his graduate student Joydeep Munshi have been running molecular models of organic solar cell production processes, and designing a framework to determine the optimal engineering choices. They described the computational effort and associated findings in the May issue of IEEE Computing in Science and Engineering.

"When engineers make solar cells, they mix two organic molecules in a solvent and evaporate the solvent to create a mixture which helps with the exciton conversion and electron transport," Balasubramanian said. "We mimicked how these cells are created, in particular the bulk heterojunction -- the absorption layer of a solar cell. Basically, we're trying to understand how structure changes correlate with the efficiency of the solar conversion?"

Balasubramanian uses what he calls 'physics-informed machine learning'. His research combines coarse-grained simulation -- using approximate molecular models that represent the organic materials -- and machine learning. Balasubramanian believes the combination helps prevent artificial intelligence from coming up with unrealistic solutions.

"A lot of research uses machine learning on raw data," Balasubramanian said. "But more and more, there's an interest in using physics-educated machine learning. That's where I think lies the most benefit. Machine learning per se is simply mathematics. There's not a lot of real physics involved in it."

Writing in Computational Materials Science in February 2021, Balasubramanian and Munshi along with Wei Chen (Northwestern University), and TeYu Chien (University of Wyoming) described results from a set of virtual experiments on Frontera testing the effects of various design changes. These included altering the proportion of donor and receptor molecules in the bulk heterojunctions, and the temperature and amount of time spent in annealing -- a cooling and hardening process that contributes to the stability of the product.

They harnessed the data to train a class of machine learning algorithms known as support vector machines to identify parameters in the materials and production process that would generate the most energy conversion efficiency, while maintaining structural strength and stability. Coupling these methods together, Balasubramanian's team was able to reduce the time required to reach an optimal process by 40%.

"At the end of the day, molecular dynamics is the physical engine. That's what captures the fundamental physics," he said. "Machine learning looks at numbers and patterns, and evolutionary algorithms facilitate the simulations."

Trade-Offs and Limitations

Like many industrial processes, there are trade-offs involved in tweaking any facet of the manufacturing process. Faster cooling may help increase power efficiency, but it may make the material brittle and prone-to-break, for instance. Balasubramanian and his team employed a multi-objective optimization algorithm that balances the benefits and drawbacks of each change to derive the overall optimal manufacturing process.

Flowchart describing steps in a typical coupled Cuckoo Search-Coarse Grained Molecular Dynamics (CS-CGMD) algorithm. The dashed box represents the augmented machine learned exploration of the regions of interest to supplement ill-performed nests with newer alternatives during each CS optimization generation. [Credit: Ganesh Balasubramanian, Joydeep Munshi, Lehigh University]

"When you try to optimize one particular variable, you are looking at the problem linearly," he said. "But most of these efforts have multi-pronged challenges that you're trying to solve simultaneously. There are trade-offs that you need to make, and synergistic roles that you must capture, to come to the right design."

Balasubramanian's simulations matched experimental results. They determined that the make-up of the heterojunction and the annealing temperature/timing have the largest effects on overall efficiency. They also found what proportion of the materials in the heterojunction is best for efficiency.

"There are certain conditions identified in literature which people claim are the best conditions for efficiency for those select molecules and processing behavior," he said. "Our simulation were able to validate those and show that other possible criteria would not give you the same performance. We were able to realize the truth, but from the virtual world."

With an award of more time on Frontera in 2021-22, Balasubramanian will add further layers to the machine learning system to make it more robust. He plans to add experimental data, as well as other modalities of computer models, such as electronic structure calculations.

"Heterogeneity in the data will improve the results," he said. "We plan to do first principle simulations of materials and then feed that data into the machine learning model, as well as data from coarse-grained simulations."

Balasubramanian believes that current organic photovoltaics may be reaching the limits of their efficiency. "There's a wall that's hard to penetrate and that's the material," he said. "These molecules we've used can only go so far. The next thing to try is to use our framework with other molecules and advanced materials."

His team mined the literature to understand the features that increase solar efficiency and then trained a machine learning model to identify potential new molecules with ideal charge transport behaviors. They published their research in the Journal of Chemical Information and Modeling. Future work on Frontera will use Balasubramanian's framework to explore and computationally test these alternative materials, assuming they can be produced.

"Once established, we can take realistic molecules that are made in the lab and put them in the framework we've created," he said. "If we discover new materials that perform well, it will reduce the cost of solar power generation devices and help Mother Earth."

Balasubramanian's research harnesses the two things that computer simulations are critical for, he says. "One is to understand the science that we cannot study with the tools that we have in the real world. And the other is to expedite the science - streamline what we really have to do, which reduces our cost and time to make things and physically test them."

INFORMATION:


[Attachments] See images for this press release:
Engineers apply physics-informed machine learning to solar cell production

ELSE PRESS RELEASES FROM THIS DATE:

Understanding gut inflammation may hold clues to mitigating Parkinson's onset

2021-06-09
GRAND RAPIDS, Mich. (JUNE 8, 2021) -- Chronic inflammation in the gut may propel processes in the body that give rise to Parkinson's disease, according to a study by scientists at Van Andel Institute and Roche. The study, published in Free Neuropathology, is the latest in a growing list that links the gut and the immune system to Parkinson's. The researchers' findings in an experimental mouse model of gut inflammation track with several large-scale epidemiological studies that show an association between Parkinson's and inflammatory bowel diseases, such as ulcerative colitis and Crohn's disease. Epidemiological evidence from other groups indicates the risk of developing Parkinson's fades in certain people whose ...

Bacteria-sized robots take on microplastics and win by breaking them down

Bacteria-sized robots take on microplastics and win by breaking them down
2021-06-09
Small pieces of plastic are everywhere, stretching from urban environments to pristine wilderness. Left to their own devices, it can take hundreds of years for them to degrade completely. Catalysts activated by sunlight could speed up the process, but getting these compounds to interact with microplastics is difficult. In a proof-of-concept study, researchers reporting in ACS Applied Materials & Interfaces developed self-propelled microrobots that can swim, attach to plastics and break them down. While plastic products are omnipresent indoors, plastic waste and broken bits now litter the outdoors, too. The smallest of these ...

Social media use one of four factors related to higher COVID-19 spread rates early on

2021-06-09
TORONTO, June 9, 2021 - Researchers from York University and the University of British Columbia have found social media use to be one of the factors related to the spread of COVID-19 within dozens of countries during the early stages of the pandemic. The researchers say this finding resembles other examples of social media misinformation ranging from the initial phase of vaccine rollout to the 2021 Capitol riot in the United States. Countries with high social media use leading to off-line political action prior to the pandemic, as surveyed before the pandemic by V-Dem (a database from the University of Gothenburg), showed ...

Researchers tame silicon to interact with light for next-generation microelectronics

Researchers tame silicon to interact with light for next-generation microelectronics
2021-06-09
Skoltech researchers and their colleagues from RAS Institute for Physics of Microstructures, Lobachevsky State University of Nizhny Novgorod, ITMO University, Lomonosov Moscow State University, and A.M. Prokhorov General Physics Institute have found a way to increase photoluminescence in silicon, the notoriously poor emitter and absorber of photons at the heart of all modern electronics. This discovery may pave the way to photonic integrated circuits, boosting their performance. The paper was published in the journal Laser and Photonics Reviews. "Natural selection" in semiconductor technology ...

For early amphibians, a new lifestyle meant a new spine

2021-06-09
Vertebrate life began in the water, but around 340-360 million years ago, four-limbed creatures, or tetrapods, made the transition onto land. In the years that followed, some species adapted to terrestrial life, while others turned back to the water and readapted to an aquatic lifestyle. A new study of these early amphibians, published in the journal PLOS ONE and led by Penn paleontologist Aja Carter, suggests that these environmental shifts left an impression--on the shape of the animals' spines. "I'm interested in how the shapes of the vertebrae affect how animals move," she says. "Our findings suggest that, in at least one part of the vertebrae, the shape of the bones ...

Forget wearables: Future washable smart clothes powered by Wi-Fi will monitor your health

Forget wearables: Future washable smart clothes powered by Wi-Fi will monitor your health
2021-06-09
WEST LAFAYETTE, Ind. - Purdue University engineers have developed a method to transform existing cloth items into battery-free wearables resistant to laundry. These smart clothes are powered wirelessly through a flexible, silk-based coil sewn on the textile. In the near future, all your clothes will become smart. These smart cloths will outperform conventional passive garments, thanks to their miniaturized electronic circuits and sensors, which will allow you to seamlessly communicate with your phone, computer, car and other machines. This smart clothing will not only make you more productive but also check on your health status and even call for help if you suffer an accident. The reason why this smart clothing ...

Nearly 1 in 5 patients who die from unexplained sudden cardiac death have suspicious gene

2021-06-09
As many as 450,000 Americans die every year from a sudden, fatal heart condition, and in slightly more than one in ten cases the cause remains unexplained even after an autopsy. Researchers from the University of Maryland School of Medicine (UMSOM) and their colleagues found that nearly 20 percent of patients with unexplained sudden cardiac death - most of whom were under age 50 - carried rare genetic variants. These variants likely raised their risk of sudden cardiac death. In some cases, their deaths may have been prevented if their doctors had known about their genetic predisposition to heart disease. The study findings were published ...

Scientists identify distinctive deep infrasound rumbles of space launches

2021-06-09
WASHINGTON--After their initial blast, space rockets shoot away from the Earth with rumbles in infrasound, soundwaves too low to be heard by human ears that can travel thousands of miles. New research used a system for monitoring nuclear tests to track the infrasound from 1,001 rocket launches. The research identified the distinctive sounds from seven different types of rockets, including the Space Shuttles, Falcon 9 rockets, various Soyuz rockets, the European Space Agency's Ariane 5, Russian Protons and several types of Chinese Long March rockets. In some cases, like the Space Shuttle and the Falcon 9, the researchers were also able to identify the various stages of the rockets' journey. https://youtu.be/IfMtEcNkkho The ...

Smokers needed angioplasty and stenting a decade before non-smokers

2021-06-09
Smokers needed their blocked arteries fixed nearly a decade earlier than non-smokers, and patients with obesity underwent these procedures four years earlier than non-obese patients, according to a new statewide study. The research included patients without a history of heart attack who were treated at hospitals across Michigan participating in BMC2, the Blue Cross Blue Shield of Michigan Cardiovascular Consortium. The patients had undergone angioplasty and/or stenting to widen or unblock their coronary arteries and restore blood flow. Almost all of them had at least one traditional ...

New research a 'step change' for diabetes patients

New research a step change for diabetes patients
2021-06-09
Millions of people with diabetes are at risk of developing foot ulcers, which often lead to amputations and other health complications. Now, Scientists from the Centre for Biomechanics and Rehabilitation Technologies (CRBT) have developed a new method to reliably detect this risk without the need for complex electronic in-shoe sensors. Dr Panagiotis Chatzistergos, Associate Professor in Orthopaedic Biomechanics, explained: "In the UK alone, 169 people have a toe, foot or limb amputated as a result of diabetes every week, yet importantly up to 80% of these amputations could have been prevented with correct management. "Routine overloading ...

LAST 30 PRESS RELEASES:

Engineers uncover why tiny particles form clusters in turbulent air

GLP-1RA drugs dramatically reduce death and cardiovascular risk in psoriasis patients

Psoriasis linked to increased risk of vision-threatening eye disease, study finds

Reprogramming obesity: New drug from Italian biotech aims to treat the underlying causes of obesity

Type 2 diabetes may accelerate development of multiple chronic diseases, particularly in the early stages, UK Biobank study suggests

Resistance training may improve nerve health, slow aging process, study shows

Common and inexpensive medicine halves the risk of recurrence in patients with colorectal cancer

SwRI-built instruments to monitor, provide advanced warning of space weather events

Breakthrough advances sodium-based battery design

New targeted radiation therapy shows near-complete response in rare sarcoma patients

Does physical frailty contribute to dementia?

Soccer headers and brain health: Study finds changes within folds of the brain

Decoding plants’ language of light

UNC Greensboro study finds ticks carrying Lyme disease moving into western NC

New implant restores blood pressure balance after spinal cord injury

New York City's medical specialist advantage may be an illusion, new NYU Tandon research shows

Could a local anesthetic that doesn’t impair motor function be within reach?

1 in 8 Italian cetacean strandings show evidence of fishery interactions, with bottlenose and striped dolphins most commonly affected, according to analysis across four decades of data and more than 5

In the wild, chimpanzees likely ingest the equivalent of several alcoholic drinks every day

Warming of 2°C intensifies Arctic carbon sink but weakens Alpine sink, study finds

Bronze and Iron Age cultures in the Middle East were committed to wine production

Indian adolescents are mostly starting their periods at an earlier age than 25 years ago

Temporary medical centers in Gaza known as "Medical Points" (MPs) treat an average of 117 people daily with only about 7 staff per MP

Rates of alcohol-induced deaths among the general population nearly doubled from 1999 to 2024

PLOS One study: In adolescent lab animals exposed to cocaine, High-Intensity Interval Training boosts aversion to the drug

Scientists identify four ways our bodies respond to COVID-19 vaccines

Stronger together: A new fusion protein boosts cancer immunotherapy

Hidden brain waves as triggers for post-seizure wandering

Music training can help the brain focus

Researcher develop the first hydride ion prototype battery

[Press-News.org] Engineers apply physics-informed machine learning to solar cell production
Lehigh University researchers use Frontera supercomputer to simulate photovoltaic fabrication, train AI to optimize energy production