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

NRL achieves highest open-circuit voltage for quantum dot solar cells

2013-09-13
(Press-News.org) WASHINGTON--U.S. Naval Research Laboratory (NRL) research scientists and engineers in the Electronics Science and Technology Division have demonstrated the highest recorded open-circuit voltages for quantum dot solar cells to date. Using colloidal lead sulfide (PbS) nanocrystal quantum dot (QD) substances, researchers achieved an open-circuit voltage (VOC) of 692 millivolts (mV) using the QD bandgap of a 1.4 electron volt (eV) in QD solar cell under one-sun illumination.

"These results clearly demonstrate that there is a tremendous opportunity for improvement of open-circuit voltages greater than one volt by using smaller QDs in QD solar cells," said Woojun Yoon, Ph.D., NRC postdoctoral researcher, NRL Solid State Devices Branch. "Solution processability coupled with the potential for multiple exciton generation processes make nanocrystal quantum dots promising candidates for third generation low-cost and high-efficiency photovoltaics."

Despite this remarkable potential for high photocurrent generation, the achievable open-circuit voltage is fundamentally limited due to non-radiative recombination processes in QD solar cells. To overcome this boundary, NRL researchers have reengineered molecular passivation in metal-QD Schottky junction (unidirectional metal to semiconductor junction) solar cells capable of achieving the highest open-circuit voltages ever reported for colloidal QD based solar cells.

Experimental results demonstrate that by improving the passivation of the PbS QD surface through tailored annealing of QD and metal-QD interface using lithium fluoride (LiF) passivation with an optimized LiF thickness. This proves critical for reducing dark current densities by passivating localized traps in the PbS QD surface and metal-QD interface close to the junction, therefore minimizing non-radiative recombination processes in the cells.

Over the last decade, Department of Defense (DoD) analyses and the department's recent FY12 Strategic Sustainability Performance Plan, has cited the military's fossil fuel dependence as a strategic risk and identified renewable energy and energy efficiency investments as key mitigation measures. Research at NRL is committed to supporting the goals and mission of the DoD by providing basic and applied research toward mission-ready renewable and sustainable energy technologies that include hybrid fuels and fuel cells, photovoltaics, and carbon-neutral biological microorganisms.



INFORMATION:



ELSE PRESS RELEASES FROM THIS DATE:

Inheritance of lifespan is sex-dependent in fruit flies

2013-09-13
This news release is available in German. Like mother, like daughter; like father, like son. Evolutionary biologists at the universities in Bielefeld (Germany) and Uppsala (Sweden) have now shown that this proverb also applies to inheriting a long life – at least for fruit flies (Drosophila). The research team found that the descendants of these insects mostly inherit their lifespan from their own sex: male descendants will very probably live about as long as their fathers; female descendants, about as long as their mothers. The scientists have published their findings ...

Young people choose education based on parents' background

2013-09-13
Even though Danish students have equal access to education, their choice of studies is still influenced by social class. Young people from working class backgrounds are motivated by studies with a clear job profile and high income, while prestige and studies with a strong identity appeal to young people of parents with university degrees when choosing which studies to pursue. This is what researchers from the University of Copenhagen conclude in a new study. Students who have chosen to study medicine, architecture, economy and sociology often come from homes where the ...

Vaccination with GM2-KLH-QS21 does not improve outcome of melanomas patients in EORTC study

2013-09-13
Results of an EORTC study published in the Journal of Clinical Oncology show that vaccination with GM2/KLH-QS-21 does not benefit patients with stage II melanoma. Vaccination with GM2/KLH-QS-21 stimulates the production of antibodies to the GM2 ganglioside, an antigen expressed by many melanomas. Serological response to GM2 was shown to be a positive prognostic factor in patients with melanoma and was the rationale for this trial. The idea of treating cancer with a vaccine has been around since the first vaccines against infectious disease were developed. The GM2 ganglioside, ...

Fate of new genes cannot be predicted

2013-09-13
New versions of genes, called alleles, can appear by mutation in populations. Even when these new alleles turn the individuals carrying them more fit to survive and reproduce, the most likely outcome is that they will get lost from the populations. The theory that explains these probabilities has been postulated by the scientist J.B.S. Haldane almost 90 years ago. This theory has become the cornerstone of modern population genetics, with studies on adaptation to novel environments and conservation of species, for example, being based on it. However, until now there were ...

Researchers use machine learning to boil down the stories that wearable cameras are telling

2013-09-13
Computers will someday soon automatically provide short video digests of a day in your life, your family vacation or an eight-hour police patrol, say computer scientists at The University of Texas at Austin. The researchers are working to develop tools to help make sense of the vast quantities of video that are going to be produced by wearable camera technology such as Google Glass and Looxcie. "The amount of what we call 'egocentric' video, which is video that is shot from the perspective of a person who is moving around, is about to explode," said Kristen Grauman, ...

EORTC at 2013 ECCO-ESMO-ESTRO meeting in Amsterdam

2013-09-13
The EORTC will have an active presence at the 2013 ECCO-ESMO-ESTRO Meeting in Amsterdam, The Netherlands, from 27 September to 01 October 2013 and would like to call your attention to the following presentations. Society Session F. Meunier and R. Stupp are co-Chairs of the session "European Organisation for Research and Treatment of Cancer (EORTC) - Multidisciplinary Cancer Clinical Research: What are we up to in 2013?" on Saturday, 28 September 2013 from 16:00 - 18:00 in Room G102. Special sessions J. Bogaerts will chair a Special session, "Dilemma of Crossover ...

Software may be able to take over from hardware in managing caches

2013-09-13
CAMBRIDGE, Mass-- In today's computers, moving data to and from main memory consumes so much time and energy that microprocessors have their own small, high-speed memory banks, known as "caches," which store frequently used data. Traditionally, managing the caches has required fairly simple algorithms that can be hard-wired into the chips. In the 21st century, however, in order to meet consumers' expectations for steadily increasing computational power, chipmakers have had to begin equipping their chips with more and more cores, or processing units. And as cores proliferate, ...

NASA satellite sees 2 vortices circling newborn Tropical Storm Man-yi's center

2013-09-13
NASA's Terra satellite passed over newborn Tropical Storm Man-yi and captured and image that clearly showed two vortices rotating around a large center of circulation. Man-yi formed on Sept. 12 in the northwestern Pacific Ocean as the sixteenth tropical depression and by Sept. 13 it strengthened into a tropical storm. When NASA's Terra satellite passed over newborn Tropical Storm Man-yi in the northwestern Pacific Ocean on Sept. 13 at 01:15 UTC, the Moderate Resolution Imaging Spectroradiometer or MODIS instrument captured a visible image of the storm. The MODIS image ...

Catalysts team up with textiles

2013-09-13
This news release is available in German. In future, it will be much easier to produce some active pharmaceutical substances and chemical compounds than was the case to date. An international team working with chemists from the Max-Planck-Institut für Kohlenforschung in Mülheim an der Ruhr have immobilised various catalysts on nylon in a very simple way. Catalysts mediate between the reagents in a chemical reaction and control the process leading to the desired end product. When textile material is used as a support for the chemical auxiliaries, the reaction can ...

NIH clinical study establishes human model of influenza pathogenesis

2013-09-13
WHAT: A National Institutes of Health (NIH) clinical study of healthy adult volunteers who consented to be infected with the 2009 H1N1 influenza virus under carefully controlled conditions has provided researchers with concrete information about the minimum dose of virus needed to produce mild-to-moderate illness. The study also gives a clearer picture of how much time elapses between a known time of infection, the start of viral shedding (a signal of contagiousness), the development of an immune response, and the onset and duration of influenza symptoms. The data obtained ...

LAST 30 PRESS RELEASES:

Shaking it up: An innovative method for culturing microbes in static liquid medium

Greener and cleaner: Yeast-green algae mix improves water treatment

Acquired immune thrombotic thrombocytopenic purpura (TTP) associated with inactivated COVID-19 vaccine CoronaVac

CIDEC as a novel player in abdominal aortic aneurysm formation

Artificial intelligence: a double-edged sword for the environment?

Current test accommodations for students with blindness do not fully address their needs

Wide-incident-angle wideband radio-wave absorbers boost 5G and beyond 5G applications

A graph transformer with boundary-aware attention for semantic segmentation

C-Path announces key leadership appointments in neurodegenerative disease research

First-of-its-kind analysis of U.S. national data reveals significant disparities in individual well-being as measured by lifespan, education, and income

Exercise programs help cut new mums’ ‘baby blues’ severity and major depression risk

Gut microbiome changes linked to onset of clinically evident rheumatoid arthritis

Signals from the gut could transform rheumatoid arthritis treatment

Pioneering research reveals some of the world’s least polluting populations are at much greater risk of flooding fuelled by climate change

UK’s health data should be recognized as critical national infrastructure, says independent review

A 36-gene predictive score of anti-cancer drug resistance anticipates cancer therapy outcomes

Someone flirts with your spouse. Does that make your partner appear more attractive?

Hourglass-shaped stent could ease severe chest pain from microvascular disease

United Nations ratifies framework to protect people on cash app

Oklahoma State basketball team joins the Nation of Lifesavers

Power of aesthetic species on social media boosts wildlife conservation efforts, say experts

Researchers develop robotic sensory cilia that monitor internal biomarkers to detect and assess airway diseases

Could crowdsourcing hold the key to early wildfire detection?

Reconstruction of historical seasonal influenza patterns and individual lifetime infection histories in humans based on antibody profiles

New study traces impact of COVID-19 pandemic on global movement and evolution of seasonal flu

Presenting a Janus channel of membranes for complete oil-and-water separation

COVID-19 restrictions altered global dispersal of influenza viruses

Disconnecting hepatic vagus nerve restores balance to liver and brain circadian clocks, reducing overeating in mice

Mechanosensory origins of “wet dog shakes” – a tactic used by many hairy mammals – uncovered in mice

New study links liver-brain communication to daily eating patterns

[Press-News.org] NRL achieves highest open-circuit voltage for quantum dot solar cells