Solar power's future brawl

Simulations help North and South Dakota researchers decide which technology would make a better solar collector, quantum dot or nanowire

2013-10-02

(Press-News.org) WASHINGTON, D.C. Oct. 1, 2013 -- A trio of researchers at North Dakota State University and the University of South Dakota have turned to computer modeling to help decide which of two competing materials should get its day in the sun as the nanoscale energy-harvesting technology of future solar panels -- quantum dots or nanowires.

Andrei Kryjevski and his colleagues, Dimitri Kilin and Svetlana Kilina, report in AIP Publishing's Journal of Renewable and Sustainable Energy that they used computational chemistry models to predict the electronic and optical properties of three types of nanoscale (billionth of a meter) silicon structures with a potential application for solar energy collection: a quantum dot, one-dimensional chains of quantum dots and a nanowire. The ability to absorb light is substantially enhanced in nanomaterials compared to those used in conventional semiconductors. Determining which form -- quantum dots or nanowire -- maximizes this advantage was the goal of the numerical experiment conducted by the three researchers.

"We used Density Functional Theory, a computational approach that allows us to predict electronic and optical properties that reflect how well the nanoparticles can absorb light, and how that effectiveness is affected by the interaction between quantum dots and the disorder in their structures," Kryjevski said. "This way, we can predict how quantum dots, quantum dot chains and nanowires will behave in real life even before they are synthesized and their working properties experimentally checked."

The simulations made by Kryjevski, Kilin and Kilina indicated that light absorption by silicon quantum dot chains significantly increases with increased interactions between the individual nanospheres in the chain. They also found that light absorption by quantum dot chains and nanowires depends strongly on how the structure is aligned in relation to the direction of the photons striking it. Finally, the researchers learned that the atomic structure disorder in the amorphous nanoparticles results in better light absorption at lower energies compared to crystalline-based nanomaterials.

"Based on our findings, we believe that putting the amorphous quantum dots in an array or merging them into a nanowire are the best assemblies for maximizing the efficiency of silicon nanomaterials to absorb light and transport charge throughout a photovoltaic system," Kryjevski said. "However, our study is only a first step in a comprehensive computational investigation of the properties of semiconductor quantum dot assemblies.

"The next steps are to build more realistic models, such as larger quantum dots with their surfaces covered by organic ligands and simulate the processes that occur in actual solar cells," he added.

INFORMATION:

The article, "Amorphous Silicon Nanomaterials: Quantum Dots Versus Nanowires" by Andrei Kryjevski, Dmitri Kilin and Svetlana Kilina, appears in the Journal of Renewable and Sustainable Energy. See: http://dx.doi.org/10.1063/1.4817728

ABOUT THE JOURNAL

The Journal of Renewable and Sustainable Energy is an interdisciplinary, peer-reviewed journal covering all areas of renewable and sustainable energy that apply to the physical science and engineering communities. See: http://jrse.aip.org

ELSE PRESS RELEASES FROM THIS DATE:

Rensselaer researchers propose new theory to explain seeds of life in asteroids

2013-10-02

Troy, N.Y. – A new look at the early solar system introduces an alternative to a long-taught, but largely discredited, theory that seeks to explain how biomolecules were once able to form inside of asteroids. In place of the outdated theory, researchers at Rensselaer Polytechnic Institute propose a new theory – based on a richer, more accurate image of magnetic fields and solar winds in the early solar system, and a mechanism known as multi-fluid magneto-hydrodynamics – to explain the ancient heating of the asteroid belt. Although today the asteroid belt between Mars ...

Renal risk index: A clinical tool to predict the risk of end-stage renal disease

2013-10-02

Ann Arbor, Mich. — End-stage renal disease is one of the major public health problems among solid organ transplant recipients that is associated with death after transplant and high cost of care. Using the national data of 43,514 liver transplant recipients, researchers at University of Michigan researchers in collaboration with Arbor Research Collaborative for Health created and validated a risk score called renal risk index based upon the liver transplant recipient's characteristics at the time of transplant to predict the post- transplant end stage renal disease. ...

Out-of-pocket medical spending will drop for many under Affordable Care Act, study finds

2013-10-02

Out-of-pocket medical expenses will decline for most consumers who become newly insured or change their source of health insurance under the federal Affordable Care Act, according to a new RAND Corporation study. The study found that overall the Affordable Care Act will have a varied impact on health spending by individuals and families, depending primarily on their income and whether they would have been uninsured in 2016 without the program. People who will be newly insured and do not qualify for government subsidies are those who are most likely to see increased ...

New genetic discovery could reduce the guesswork in drug dosing

2013-10-02

COLUMBUS, Ohio – The discovery of genetic differences affecting up to a third of the population could take the guesswork out of prescribing the correct dose of 25 percent of drugs currently on the market, researchers say. The scientists found two genetic variants that alter the activity level of an enzyme responsible for processing, or metabolizing, drugs ranging from the painkiller codeine to the breast cancer drug tamoxifen. The Ohio State University researchers who found these differences say that pending additional research, the variants are good candidates for ...

Notre Dame study: The face is the focus for a person wielding a gun

2013-10-02

A person wielding a gun focuses more intently on the face of an opponent with a gun, presumably to try to determine that person's likelihood of pulling the trigger, according to a new study that builds on gun-in-hand research from the University of Notre Dame. Notre Dame Associate Professor of Psychology James Brockmole, who specializes in human cognition and how the visual world guides behavior, conducted the research at Notre Dame with Adam Biggs, currently a post-doctoral fellow in the Duke Institute for Brain Sciences and the Center for Cognitive Neuroscience, and ...

Lactation may be linked to aggressive cancer in Mexican women

2013-10-02

Scientific data suggest that a woman reduces her risk of breast cancer by breastfeeding, having multiple children and giving birth at a younger age. A study led by the University of California, San Diego School of Medicine and recently published online by Cancer Epidemiology, Biomarkers & Prevention, indicates that women of Mexican descent may not fit that profile. In fact, results suggest that women of Mexican descent with more children and those who breastfeed are more likely to be diagnosed with an aggressive form of breast cancer. During the four-year Ella Binational ...

UW scientist sniffs out possible new tick species

2013-10-02

MADISON — In June 2012, Tony Goldberg returned from one of his frequent trips to Kibale National Park, an almost 500-square-mile forest in western Uganda where he studies how infectious diseases spread and evolve in the wild. But he didn't return alone. "When I got back to the U.S., I realized I had a stowaway," says Goldberg, professor of pathobiological sciences at the University of Wisconsin-Madison School of Veterinary Medicine and associate director for research in the UW-Madison Global Health Institute. "When you first realize you have a tick up your nose, it takes ...

Recent study reduces Casimir force to lowest recorded level

2013-10-02

A research team that includes a physics professor at Indiana University-Purdue University Indianapolis (IUPUI) has recorded a drastically reduced measurement of the Casimir effect, a fundamental quantum phenomenon experienced between two neutral bodies that exist in a vacuum. For more than 60 years, scientists have studied the peculiar electromagnetic interaction between two neutral objects. The Casimir effect, a long-standing point of study in quantum physics, refers to this unavoidable physical force that exists between the objects, even when those objects are placed ...

Hey, wait a minute! Waiting actually makes people more patient, study finds

2013-10-02

People place higher value on what they're waiting for; higher value makes them more patient Let's face it – no one likes to wait. We're a culture of instant gratification. But what if the very act we dislike can actually help make us more patient and help us make better financial decisions? According to a recent study by Ayelet Fishbach, Jeffrey Breakenridge Keller Professor of Behavioral Science and Marketing at the University of Chicago Booth School of Business, waiting actually does make people more patient, which can provide a payoff for consumers by helping them ...

Chronic use of prescription painkillers continues following bariatric surgery

2013-10-02

DENVER, October 1, 2013 – Chronic use of prescription painkillers, also known as opioids, among obese patients prior to bariatric surgery continues after surgery, according to a new Kaiser Permanente study published today in the Journal of the American Medical Association. Researchers examined the electronic medical records of 11,719 obese patients who underwent bariatric surgery between 2005-2009 at one of 10 U.S. sites in the Scalable Partnering Network. Participating patients were evaluated one year before and one year after surgery. Seventy-seven percent of the obese ...

LAST 30 PRESS RELEASES:

Jeonbuk National University researchers develop DDINet for accurate and scalable drug-drug interaction prediction

IEEE researchers achieve 20x signal boost in cerebral blood flow monitoring with next-generation interferometric diffusing wave spectroscopy

Flexible polymer‑based electronics for human health monitoring: A safety‑level‑oriented review of materials and applications

Mining the dark transcriptome: University of Toronto Engineering researchers create the first potential drug molecules from long noncoding RNA

[Press-News.org] Solar power's future brawl
Simulations help North and South Dakota researchers decide which technology would make a better solar collector, quantum dot or nanowire