Doe Science news source
The DOE Science News Source is a Newswise initiative to promote research news from the Office of Science of the DOE to the public and news media.
  • 2018-01-24 10:00:19
  • Article ID: 688341

New Discovery Could Improve Organic Solar Cell Performance

Science team at Berkeley Lab-based DOE science center unravels the mystery of a multiplier mechanism in an organic crystal

  • Solar panel array.

New Discovery Could Improve Organic Solar Cell Performance

Science team at Berkeley Lab-based DOE science center unravels the mystery of a multiplier mechanism in an organic crystal

While there is a growing market for organic solar cells ­­– they contain materials that are cheaper, more abundant, and more environmentally friendly than those used in typical solar panels – they also tend to be less efficient in converting sunlight to electricity than conventional solar cells.

Now, scientists who are members of the Center for Computational Study of Excited-State Phenomena in Energy Materials (C2SEPEM) a new energy materials-related science center based at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), have solved a mystery that could lead to gains in efficiency. 

They pinpointed the source of an ultrafast and efficient process that spawns several carriers of electrical charge from a single particle of light in organic crystals that are integral to this increasingly popular form of solar cells.

This process – called “singlet fission” because it is akin to the splitting of atomic nuclei in nuclear fission to create two lighter atoms from a heavier one – holds promise for dramatically boosting the efficiency of organic solar cells by rapidly converting more of sunlight’s energy to electrical charges instead of losing it to heat.

The research team found a new mechanism explaining how this reaction can occur in just tens of femtoseconds (quadrillionths of a second), before other competing effects can steal away their energy. Their study was published on Dec. 29 in the journal Physical Review Letters.

“We actually discovered a new mechanism that allows us to try to design better materials,” said Steven G. Louie, director of C2SEPEM, a DOE-supported center that includes researchers from Berkeley Lab; the University of California, Los Angeles; the University of Texas at Austin; and the Georgia Institute of Technology.

Louie, a co-leader of the study, is also a senior faculty scientist in Berkeley Lab’s Materials Sciences Division and a professor of physics at UC Berkeley. C2SEPEM focuses on developing theories, methods, and software to help explain complex processes in energy-related materials.

In the splitting process, a composite particle composed of an electron, which has a negative charge, and its partner hole – a vacant electron position in a material’s atomic structure that behaves like a particle in carrying a positive charge – rapidly converts into two electron-hole pairs. This doubles the charge-carrying potential in the material while avoiding the loss of energy as heat.

“There’s a lot we still don’t understand about the fundamental physics of this process in crystalline materials that we are hoping to shed more light on,” said Jeffrey B. Neaton, associate director of C2SEPEM, who co-led the study with Louie.

Neaton is also the Associate Laboratory Director for Energy Sciences at Berkeley Lab, the director of Berkeley Lab’s Molecular Foundry, and a physics professor at UC Berkeley. “The computational method that we developed is very predictive, and we used it to understand singlet fission in a new way that may allow us to design materials even more efficient at harvesting light, for example.”

Louie noted that many past efforts had focused on just a few molecules within the material – in this case, the crystallized form of pentacene, which is composed of hydrogen and carbon – to learn about these exotic effects. But such approaches may have oversimplified the effects driving singlet fission.

“There have been many theoretical efforts to try to understand what’s going on,” he said.

In this latest study, the research team began with a large-scale view of the overall structure of the crystallized pentacene, and particularly its symmetry – the repeating patterns in its atomic framework.

“It’s like trying to explain the ocean by either looking at it molecule by molecule, or looking at a whole wave,” said Felipe H. da Jornada, a co-lead author of the study with Sivan Refaely-Abramson. Both are postdoctoral researchers at Berkeley Lab and UC Berkeley and are also affiliated with C2SEPEM.

“Our approach directly captures the whole crystal,” no matter the size, he noted.

The team used calculations performed in part at Berkeley Lab's Molecular Foundry, and supercomputing resources at the Lab's National Energy Research Scientific Computing Center to develop, model, and test their new theories of the fission process.

“We believe these theories can also be applied to very different materials,” said Refaely-Abramson, “and in this sense, theory is very important.” Prior experiments had missed some of the important clues about the crystal structure’s role in the singlet fission mechanism.

The study concludes that in order to efficiently double these electron-hole pairs, the sampled material should display a specific kind of symmetry, or repeated combinations of molecules, within its crystal structure – just as a room’s floor can display a multitude of simple, repeating patterns using the same tiles.

The efficiency of the singlet fission process appears to rely heavily on the number of molecules packed within each repeating pattern or “motif” in the crystal, and on a particular type of symmetry that in which there is a 180-degree rotation and mirroring of these motifs. This relationship between symmetry and efficiency, the researchers found, allows them to make powerful predictions on the efficiency of the overall fission.

Those predictions can only be possible, though, if the electron-hole pairs in the sample behave as wavelike objects moving throughout the whole crystal like waves in an ocean. This approach also gave them new insight about the splitting process, and how the newly created pairs must behave like waves propagating in opposite directions.

There are still several steps that must be worked out to make these findings more relevant to real-world applications, the researchers noted. In solar cells, for example, electrons must be efficiently liberated from their pairing with holes to harvest their energy and improve solar panel performance.

Understanding the doubling of charge carriers in a material may help researchers to better explain and engineer reverse processes, too – such as the technology used in some mobile phone displays that reduces the number of charge carriers (a process known as triplet fusion), said Neaton.

Louie noted that the multidisciplinary team that was assembled for the study, a key aspect of the C2SEPEM center, was integral in introducing new thinking to address a decades-old problem.

“This is one of the first important topics that we could address, and now it’s come to fruition,” he said.

NERSC and the Molecular Foundry are both DOE Office of Science User Facilities.

This work was supported by the U.S. Department of Energy’s Office of Science.

###

Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 13 Nobel Prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy’s Office of Science. For more, visit www.lbl.gov.

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

X
X
X
  • Filters

  • × Clear Filters

Squeezing Into the Best Shape

Gel uses nanoparticles for on-demand control of droplet shapes, of interest for energy storage and catalysis.

Forcing the Hand of Elusive Electrons

Current generated when light hits a material reveals electrons behaving like an elusive particle.

Single Atoms in Nano-Cages

Tiny cages can trap and release inert argon gas atoms, allowing their further study and providing a new way to capture rare gases.

Why Polymer Solar Cells Deserve Their Place in the Sun

Organic polymer solar cells show potential to provide solar power to remote microwatt sensors, wearable technology and the Wi-Fi-connected appliances constituting the "internet of things." While PSCs cannot match the durability or efficiency of inorganic solar cells, the potential to mass-produce nontoxic, disposable solar panels using roll-to-roll production makes them attractive for additional applications. In this week's Journal of Renewable and Sustainable Energy, researchers review the latest advances and remaining challenges in PSC technology.

Unwavering Juggler with Three Extra Electrons

Simulations discovered the first molecule with three extra electrons and extraordinary stability.

Electric Eel-Inspired Device Reaches 110 Volts

In an effort to create a power source for future implantable technologies, a team of researchers developed an electric eel-inspired device that produced 110 volts from gels filled with water, called hydrogels. Their results show potential for a soft power source to draw on a biological system's chemical energy. Anirvan Guha will present the research during the 62nd Biophysical Society Annual Meeting, Feb. 17-21.

Researchers Demonstrate Promising Method for Improving Quantum Information Processing

A team of researchers led by the Department of Energy's Oak Ridge National Laboratory has demonstrated a new method for splitting light beams into their frequency modes, work that could spur advancements in quantum information processing and distributed quantum computing.

Deep Dive Into How Electrons Behave

Unprecedented characterization of subsurface electronic states could lead to better semiconductors and seeing new interactions.

Higher Income Level Linked to Police Use of Force Against Black Women

Black women with higher incomes are more likely to experience a forceful police interaction during a traffic stop, finds a new study from the Brown School at Washington University in St. Louis."We found that the likelihood of exposure to each type of police use of force was significantly greater for black females with incomes over $50,000," said Robert Motley Jr.

Bringing a Hidden Superconducting State to Light

Using high-intensity pulses of infrared light, scientists found evidence of superconductivity associated with charge "stripes" in a material above the temperature at which it begins to transmit electricity without resistance--a finding that could help them design better high-temperature superconductors.


  • Filters

  • × Clear Filters

ORNL Wins Four FLC Technology Transfer Awards

Four technologies developed at the Department of Energy's Oak Ridge National Laboratory have earned 2018 Excellence in Technology Transfer Awards from the Federal Laboratory Consortium for Technology Transfer (FLC).

Pacific Northwest National Laboratory, OHSU Create Joint Research Co-Laboratory to Advance Precision Medicine

News Release PORTLAND, Ore. -- Pacific Northwest National Laboratory and OHSU today announced a joint collaboration to improve patient care by focusing research on highly complex sets of biomedical data, and the tools to interpret them.The OHSU-PNNL Precision Medicine Innovation Co-Laboratory, called PMedIC, will provide a comprehensive ecosystem for scientists to utilize integrated 'omics, data science and imaging technologies in their research in order to advance precision medicine -- an approach to disease treatment that takes into account individual variability in genes, environment and lifestyle for each person.

The Mysteries of Plasma and Solar Eruptions Earn PPPL Graduate an Astrophysics Prize

Article describes dissertation award for graduate of Princeton University Department of Astrophysical Sciences.

45-Year-Old Telescope Gets a Makeover to Demystify Dark Energy

Forty-five years ago this month, a telescope tucked inside a 14-story, 500-ton dome atop a mile-high peak in Arizona took in the night sky for the first time and recorded its observations on glass photographic plates. Today, the dome closes on the previous science chapters of the 4-meter Nicholas U. Mayall Telescope and starts preparing for its new role in creating the largest 3-D map of the universe. This map could help determine why the universe is expanding at faster and faster rates, driven by an unknown force called dark energy.

MSU Uses $3 Million NASA Grant to Find Better Ways to Regulate Dams

Michigan State University researchers, equipped with $3 million from NASA, will investigate innovative methods to improve dams so that they are less harmful to people and the environment.

Harker School Wins Second Consecutive SLAC Regional DOE Science Bowl

Twenty-four teams from 16 Bay Area high schools faced off Feb. 3 in the SLAC Regional DOE Science Bowl, a series of fast-paced question-and-answer matches that test knowledge in biology, chemistry, physics, earth and space sciences, energy and math. The competition is hosted annually by the Department of Energy's SLAC National Accelerator Laboratory.

David Asner Named Deputy Associate Laboratory Director and Head of the Instrumentation Division in Brookhaven Lab's Nuclear and Particle Physics Directorate

A particle physicist with extensive leadership and management experience, Asner will help expand a portfolio of physics programs and oversee instrumentation research and development.

UIC to Provide Energy-Saving 'Kits' with $3.1m in Funding From ComEd

The University of Illinois at Chicago's Energy Resources Center has received funding from ComEd to provide energy-efficient LED light bulbs, advanced power strips, and educational material to income-qualified participants in northern Illinois.As part of a $3.1 million year-long investment, the utility company will fund the Low Income Kit Energy (LIKE) program, allowing engineers at UIC's Energy Resources Center to provide energy-saving kits to 35,000 eligible individuals and/or families.

DOE's HPC4Manufacturing Program Seeks Industry Proposals

The Department of Energy (DOE) on Feb. 1 announced up to $3 million will be made available to U.S. manufacturers for public/private projects aimed at applying high performance computing to industry challenges for the advancement of energy innovation.

Elke-Caroline Aschenauer Awarded Prestigious Humboldt Research Award

UPTON, NY -- Elke-Caroline Aschenauer, a senior physicist at the U.S. Department of Energy's Brookhaven National Laboratory, has been awarded a Humboldt Research Award for her contributions to the field of experimental nuclear physics. This prestigious international award--issued by the Alexander von Humboldt Foundation in Bonn, Germany--comes with a prize of EUR60,000 (more than $70,000 U.


  • Filters

  • × Clear Filters

Squeezing Into the Best Shape

Gel uses nanoparticles for on-demand control of droplet shapes, of interest for energy storage and catalysis.

Forcing the Hand of Elusive Electrons

Current generated when light hits a material reveals electrons behaving like an elusive particle.

Single Atoms in Nano-Cages

Tiny cages can trap and release inert argon gas atoms, allowing their further study and providing a new way to capture rare gases.

Unwavering Juggler with Three Extra Electrons

Simulations discovered the first molecule with three extra electrons and extraordinary stability.

Deep Dive Into How Electrons Behave

Unprecedented characterization of subsurface electronic states could lead to better semiconductors and seeing new interactions.

How Bacteria Produce Manganese Oxide Nanoparticles

Multiple techniques to characterize an enzyme complex shed light on how bacteria create particles and contribute to global cycles.

Meet the Director: Sergei Nagaitsev

This is one in a series of profiles on directors of the SC-stewarded user facilities. This profile features Sergei Nagaitsev, director of the Fermilab Accelerator Complex.

From 100,000 to 8: Representing Complex Aerosol Patterns with Far Fewer Particles

Study shows how aerosols interacting with clouds can be accurately captured by sparse set of representative particles.

Atomic Vibes During Melting?

Where does the heat go when a glass melts into a liquid? Not to changing the vibrations of atoms....

Taking Solar Energy to the Edge

Engineered stacked perovskite layers harvest light or create light via layer edges.


Spotlight

Thursday February 15, 2018, 12:05 PM

Insights on Innovation in Energy, Humanitarian Aid Highlight UVA Darden's Net Impact Week

University of Virginia Darden School of Business

Friday February 09, 2018, 11:05 AM

Ivy League Graduate, Writer and Activist with Dyslexia Visits CSUCI to Reframe the Concept of Learning Disabilities

California State University, Channel Islands

Wednesday January 17, 2018, 12:05 PM

Photographer Adam Nadel Selected as Fermilab's New Artist-in-Residence for 2018

Fermi National Accelerator Laboratory (Fermilab)

Wednesday January 17, 2018, 12:05 PM

Fermilab Computing Partners with Argonne, Local Schools for Hour of Code

Fermi National Accelerator Laboratory (Fermilab)

Wednesday December 20, 2017, 01:05 PM

Q&A: Sam Webb Teaches X-Ray Science from a Remote Classroom

SLAC National Accelerator Laboratory

Monday December 18, 2017, 01:05 PM

The Future of Today's Electric Power Systems

Rensselaer Polytechnic Institute (RPI)

Monday December 18, 2017, 12:05 PM

Supporting the Development of Offshore Wind Power Plants

Rensselaer Polytechnic Institute (RPI)

Tuesday October 03, 2017, 01:05 PM

Stairway to Science

Argonne National Laboratory

Thursday September 28, 2017, 12:05 PM

After-School Energy Rush

Argonne National Laboratory

Thursday September 28, 2017, 10:05 AM

Bringing Diversity Into Computational Science Through Student Outreach

Brookhaven National Laboratory

Thursday September 21, 2017, 03:05 PM

From Science to Finance: SLAC Summer Interns Forge New Paths in STEM

SLAC National Accelerator Laboratory

Thursday September 07, 2017, 02:05 PM

Students Discuss 'Cosmic Opportunities' at 45th Annual SLAC Summer Institute

SLAC National Accelerator Laboratory

Thursday August 31, 2017, 05:05 PM

Binghamton University Opens $70 Million Smart Energy Building

Binghamton University, State University of New York

Wednesday August 23, 2017, 05:05 PM

Widening Horizons for High Schoolers with Code

Argonne National Laboratory

Saturday May 20, 2017, 12:05 PM

Rensselaer Polytechnic Institute Graduates Urged to Embrace Change at 211th Commencement

Rensselaer Polytechnic Institute (RPI)

Monday May 15, 2017, 01:05 PM

ORNL, University of Tennessee Launch New Doctoral Program in Data Science

Oak Ridge National Laboratory

Friday April 07, 2017, 11:05 AM

Champions in Science: Profile of Jonathan Kirzner

Department of Energy, Office of Science

Wednesday April 05, 2017, 12:05 PM

High-Schooler Solves College-Level Security Puzzle From Argonne, Sparks Interest in Career

Argonne National Laboratory

Tuesday March 28, 2017, 12:05 PM

Champions in Science: Profile of Jenica Jacobi

Department of Energy, Office of Science

Friday March 24, 2017, 10:40 AM

Great Neck South High School Wins Regional Science Bowl at Brookhaven Lab

Brookhaven National Laboratory

Wednesday February 15, 2017, 04:05 PM

Middle Schoolers Test Their Knowledge at Science Bowl Competition

Argonne National Laboratory

Friday January 27, 2017, 04:00 PM

Haslam Visits ORNL to Highlight State's Role in Discovering Tennessine

Oak Ridge National Laboratory

Tuesday November 08, 2016, 12:05 PM

Internship Program Helps Foster Development of Future Nuclear Scientists

Oak Ridge National Laboratory

Friday May 13, 2016, 04:05 PM

More Than 12,000 Explore Jefferson Lab During April 30 Open House

Thomas Jefferson National Accelerator Facility

Monday April 25, 2016, 05:05 PM

Giving Back to National Science Bowl

Ames Laboratory

Friday March 25, 2016, 12:05 PM

NMSU Undergrad Tackles 3D Particle Scattering Animations After Receiving JSA Research Assistantship

Thomas Jefferson National Accelerator Facility

Tuesday February 02, 2016, 10:05 AM

Shannon Greco: A Self-Described "STEM Education Zealot"

Princeton Plasma Physics Laboratory

Monday November 16, 2015, 04:05 PM

Rare Earths for Life: An 85th Birthday Visit with Mr. Rare Earth

Ames Laboratory

Tuesday October 20, 2015, 01:05 PM

Meet Robert Palomino: 'Give Everything a Shot!'

Brookhaven National Laboratory

Tuesday April 22, 2014, 11:30 AM

University of Utah Makes Solar Accessible

University of Utah

Wednesday March 06, 2013, 03:40 PM

Student Innovator at Rensselaer Polytechnic Institute Seeks Brighter, Smarter, and More Efficient LEDs

Rensselaer Polytechnic Institute (RPI)

Friday November 16, 2012, 10:00 AM

Texas Tech Energy Commerce Students, Community Light up Tent City

Texas Tech University

Wednesday November 23, 2011, 10:45 AM

Don't Get 'Frosted' Over Heating Your Home This Winter

Temple University

Wednesday July 06, 2011, 06:00 PM

New Research Center To Tackle Critical Challenges Related to Aircraft Design, Wind Energy, Smart Buildings

Rensselaer Polytechnic Institute (RPI)

Friday April 22, 2011, 09:00 AM

First Polymer Solar-Thermal Device Heats Home, Saves Money

Wake Forest University

Friday April 15, 2011, 12:25 PM

Like Superman, American University Will Get Its Energy from the Sun

American University

Thursday February 10, 2011, 05:00 PM

ARRA Grant to Help Fund Seminary Building Green Roof

University of Chicago

Tuesday December 07, 2010, 05:00 PM

UC San Diego Installing 2.8 Megawatt Fuel Cell to Anchor Energy Innovation Park

University of California San Diego

Monday November 01, 2010, 12:50 PM

Rensselaer Smart Lighting Engineering Research Center Announces First Deployment of New Technology on Campus

Rensselaer Polytechnic Institute (RPI)

Friday September 10, 2010, 12:40 PM

Ithaca College Will Host Regional Clean Energy Summit

Ithaca College

Tuesday July 27, 2010, 10:30 AM

Texas Governor Announces $8.4 Million Award to Create Renewable Energy Institute

Texas Tech University

Friday May 07, 2010, 04:20 PM

Creighton University to Offer New Alternative Energy Program

Creighton University

Wednesday May 05, 2010, 09:30 AM

National Engineering Program Seeks Subject Matter Experts in Energy

JETS Junior Engineering Technical Society

Wednesday April 21, 2010, 12:30 PM

Students Using Solar Power To Create Sustainable Solutions for Haiti, Peru

Rensselaer Polytechnic Institute (RPI)

Wednesday March 03, 2010, 07:00 PM

Helping Hydrogen: Student Inventor Tackles Challenge of Hydrogen Storage

Rensselaer Polytechnic Institute (RPI)

Thursday February 04, 2010, 02:00 PM

Turning Exercise into Electricity

Furman University

Thursday November 12, 2009, 12:45 PM

Campus Leaders Showing the Way to a Sustainable, Clean Energy Future

National Wildlife Federation (NWF)

Tuesday November 03, 2009, 04:20 PM

Furman University Receives $2.5 Million DOE Grant for Geothermal Project

Furman University





Showing results

0-4 Of 2215