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

2 for 1 in solar power

2013-11-18
(Press-News.org) Contact information: Brian Walker
bjw53@cam.ac.uk
44-758-707-6777
University of Cambridge
2 for 1 in solar power

Solar cells offer the opportunity to harvest abundant, renewable energy. Although the highest energy light occurs in the ultraviolet and visible spectrum, most solar energy is in the infrared. There is a trade-off in harvesting this light, so that solar cells are efficient in the infrared but waste much of the energy available from the more energetic photons in the visible part of the spectrum.

When a photon is absorbed it creates a single electronic excitation that is then separated into an electron and a positively charged hole, irrespective of the light energy. One way to improve efficiency is to split energy available from visible photons into two, which leads to a doubling of the current in the solar cell.

Researchers in Cambridge and Mons have investigated the process in which the initial electronic excitation can split into a pair of half-energy excitations. This can happen in certain organic molecules when the quantum mechanical effect of electron spin sets the initial spin 'singlet' state to be double the energy of the alternative spin 'triplet' arrangement.

The study, published today in the journal Nature Chemistry, shows that this process of singlet fission to pairs of triplets depends very sensitively on the interactions between molecules. By studying this process when the molecules are in solution it is possible to control when this process is switched on.

When the material is very dilute, the distance between molecules is large and singlet fission does not occur. When the solution is concentrated, collisions between molecules become more frequent. The researchers find that the fission process happens as soon as just two of these molecules are in contact, and remarkably, that singlet fission is then completely efficient—so that every photon produces two triplets.

This fundamental study provides new insights into the process of singlet fission and demonstrates that the use of singlet fission is a very promising route to improved solar cells. Chemists will be able to use the results to make new materials, say the team from Cambridge's Cavendish Laboratory, who are currently working on ways to use these solutions in devices.

"We began by going back to fundamentals; looking at the solar energy challenge from a blue skies perspective," said Dr Brian Walker, a research fellow in the Cavendish Lab's Optoelectronics group, who led the study.

"Singlet fission offers a route to boosting solar cell efficiency using low-cost materials. We are only beginning to understand how this process works, and as we learn more we expect improvements in the technology to follow."

The team used a combination of laser experiments - which measure timings with extreme accuracy - with chemical methods used to study reaction mechanisms. This dual approach allowed the researchers to slow down fission and observe a key intermediate step never before seen.

"Very few other groups in the world have laser apparatus as versatile as ours in Cambridge," added Andrew Musser, a researcher who collaborated in the study. "This enabled us to get a step closer to working out exactly how singlet fission occurs."



INFORMATION:

The research was supported by the UK Engineering and Physical Sciences Research Council, the European Community's Initial Training Network SUPERIOR, the FNRS in Belgium, the Herchel Smith Fund, and the Winton Programme for the Physics of Sustainability.



ELSE PRESS RELEASES FROM THIS DATE:

Oxygen, phosphorous and early life on Earth

2013-11-18
Oxygen, phosphorous and early life on Earth Two billion years ago the Earth system was recovering from perhaps the single-most profound modification of its surface environments: the oxygenation of the atmosphere and oceans. This led ...

Study compares outcomes of device for chest compressions vs manual CPR

2013-11-18
Study compares outcomes of device for chest compressions vs manual CPR Chicago – Sten Rubertsson, M.D., Ph.D., of Uppsala University, Sweden and colleagues assessed whether cardiopulmonary resuscitation (CPR) in which chest compressions are delivered ...

Effect of lowering of body temperature for adults with cardiac arrest prior to hospital arrival

2013-11-18
Effect of lowering of body temperature for adults with cardiac arrest prior to hospital arrival Chicago – Francis Kim, M.D., of Harborview Medical Center, Seattle, and colleagues evaluated whether early prehospital cooling (lowering body temperature) improved survival ...

Effect of reducing blood pressure with medications immediately following ischemic stroke

2013-11-18
Effect of reducing blood pressure with medications immediately following ischemic stroke Chicago – Jiang He, M.D., Ph.D., of the Tulane University School of Public Health and Tropical Medicine, New Orleans, and colleagues examined whether moderate lowering of blood ...

Human error most common cause of birth asphyxia

2013-11-18
Human error most common cause of birth asphyxia Compensation claims cite poor fetal monitoring in 50 percent of cases Findings from a 15-year study published in Acta Obstetricia et Gynecologica Scandinavica, a journal of the Nordic Federation of Societies of Obstetrics and Gynecology, ...

Influence of pro-smoking media messages lasts 7 days, study finds

2013-11-18
Influence of pro-smoking media messages lasts 7 days, study finds Exposure to a single pro-smoking media message increases college-aged students' risk of using tobacco for seven days, providing new clues about the influence of media on smoking, according to a new RAND Corporation ...

Ancient, modern DNA tell story of first humans in the Americas

2013-11-18
Ancient, modern DNA tell story of first humans in the Americas CHAMPAIGN, Ill. — University of Illinois anthropology professor Ripan Malhi looks to DNA to tell the story of how ancient humans first came to the Americas and what happened to them once ...

New ISHLT nomenclature & diagnostic criteria: Antibody-mediated rejection in heart transplantation

2013-11-18
New ISHLT nomenclature & diagnostic criteria: Antibody-mediated rejection in heart transplantation Experts issue consensus statement in The Journal of Heart and Lung Transplantation New York, NY, November 18, 2013 – Antibody-mediated rejection of the transplanted ...

With board games, it's how children count that counts

2013-11-18
With board games, it's how children count that counts Boston College and Carnegie Mellon researchers find 'count-on' method yields learning gains CHESTNUT HILL, MA (Nov. 18, 2013) – Teachers and parents like to use board games to teach skills that range from fair play to ...

Body mass index may predict heart disease risk for type-2 diabetic patients new study finds

2013-11-17
Body mass index may predict heart disease risk for type-2 diabetic patients new study finds DALLAS – Researchers from the Intermountain Medical Center Heart Institute, in collaboration with researchers from Johns Hopkins University and the National Institutes ...

LAST 30 PRESS RELEASES:

UMass Amherst Nursing Professor Emerita honored as ‘Living Legend’

New guidelines aim to improve cystic fibrosis screening

Picky eaters by day, buffet by night: Butterfly, moth diets sync to plant aromas

Pennington Biomedical’s Dr. Leanne Redman honored with the E. V. McCollum Award from the American Society for Nutrition

CCNY physicists uncover electronic interactions mediated via spin waves

Researchers’ 3D-printing formula may transform future of foam

Nurture more important than nature for robotic hand

Drug-delivering aptamers target leukemia stem cells for one-two knockout punch

New study finds that over 95% of sponsored influencer posts on Twitter were not disclosed

New sea grant report helps great lakes fish farmers navigate aquaculture regulations

Strain “trick” improves perovskite solar cells’ efficiency

How GPS helps older drivers stay on the roads

Estrogen and progesterone stimulate the body to make opioids

Dancing with the cells – how acoustically levitating a diamond led to a breakthrough in biotech automation

Machine learning helps construct an evolutionary timeline of bacteria

Cellular regulator of mRNA vaccine revealed... offering new therapeutic options

Animal behavioral diversity at risk in the face of declining biodiversity

Finding their way: GPS ignites independence in older adult drivers

Antibiotic resistance among key bacterial species plateaus over time

‘Some insects are declining but what’s happening to the other 99%?’

Powerful new software platform could reshape biomedical research by making data analysis more accessible

Revealing capillaries and cells in living organs with ultrasound

American College of Physicians awards $260,000 in grants to address equity challenges in obesity care

Researchers from MARE ULisboa discover that the European catfish, an invasive species in Portugal, has a prolonged breeding season, enhancing its invasive potential

Rakesh K. Jain, PhD, FAACR, honored with the 2025 AACR Award for Lifetime Achievement in Cancer Research

Solar cells made of moon dust could power future space exploration

Deporting immigrants may further shrink the health care workforce

Border region emergency medical services in migrant emergency care

Resident physician intentions regarding unionization

Healthy nutrition and physical lifestyle choices lower cancer mortality risk for survivors, new ACS study finds

[Press-News.org] 2 for 1 in solar power