Record efficiency of 18.7 percent for flexible CIGS solar cells on plastics

Swiss researchers boost efficiency of flexible solar cells to new world record

2011-05-20

(Press-News.org) It's all about the money. To make solar electricity affordable on a large scale, scientists and engineers worldwide have long been trying to develop a low-cost solar cell, which is both highly efficient and easy to manufacture with high throughput. Now a team at Empa's Laboratory for Thin Film and Photovoltaics, led by Ayodhya N. Tiwari, has made a major step forward. "The new record value for flexible CIGS solar cells of 18.7% nearly closes the "efficiency gap" to solar cells based on polycrystalline silicon (Si) wafers or CIGS thin film cells on glass", says Tiwari. He is convinced that "flexible and lightweight CIGS solar cells with efficiencies comparable to the "best-in-class" will have excellent potential to bring about a paradigm shift and to enable low-cost solar electricity in the near future." One major advantage of flexible high-performance CIGS solar cells is the potential to lower manufacturing costs through roll-to-roll processing while at the same time offering a much higher efficiency than the ones currently on the market. What's more, such lightweight and flexible solar modules offer additional cost benefits in terms of transportation, installation, structural frames for the modules etc., i.e. they significantly reduce the so-called "balance of system" costs. Taken together, the new CIGS polymer cells exhibit numerous advantages for applications such as facades, solar farms and portable electronics. With high-performance devices now within reach, the new results suggest that monolithically-interconnected flexible CIGS solar modules with efficiencies above 16% should be achievable with the recently developed processes and concepts.

At the forefront of efficiency improvements

In recent years, thin film photovoltaic technology based on glass substrates has gained sufficient maturity towards industrial production; flexible CIGS technology is, however, still an emerging field. The recent improvements in efficiency in research labs and pilot plants – among others by Tiwari's group, first at ETH Zurich and since a couple of years now at Empa – are contributing to performance improvements and to overcoming manufacturability barriers. Working closely with scientists at FLISOM, a start-up company who is scaling up and commercializing the technology, the Empa team made significant progress in low-temperature growth of CIGS layers yielding flexible CIGS cells that are ever more efficient, up from a record value of 14.1% in 2005 to the new "high score" of 18.7% for any type of flexible solar cell grown on polymer or metal foil. The latest improvements in cell efficiency were made possible through a reduction in recombination losses by improving the structural properties of the CIGS layer and the proprietary low-temperature deposition process for growing the layers as well as in situ doping with Na during the final stage. With these results, polymer films have for the first time proven to be superior to metal foils as a carrier substrate for achieving highest efficiency. Record efficiencies of up to 17.5% on steel foils covered with impurity diffusion barriers were so far achieved with CIGS growth processes at temperatures exceeding 550°C. However, when applied to steel foil without any diffusion barrier, the proprietary low temperature CIGS deposition process developed by Empa and FLISOM for polymer films easily matched the performance achieved with high-temperature procedure, resulting in an efficiency of 17.7%. The results suggest that commonly used barrier coatings for detrimental impurities on metal foils would not be required. "Our results clearly show the advantages of the low-temperature CIGS deposition process for achieving highest efficiency flexible solar cells on polymer as well as metal foils", says Tiwari. The projects were supported by the Swiss National Science Foundation (SNSF), the Commission for Technology and Innovation (CTI), the Swiss Federal Office of Energy (SFOE), EU Framework Programmes as well as by Swiss companies W.Blösch AG and FLISOM.

Scaling up production of flexible CIGS solar cells

The continuous improvement in energy conversion efficiencies of flexible CIGS solar cells is no small feat, says Empa Director Gian-Luca Bona. "What we see here is the result of an in-depth understanding of the material properties of layers and interfaces combined with an innovative process development in a systematic manner. Next, we need to transfer these innovations to industry for large scale production of low-cost solar modules to take off." Empa scientists are currently working together with FLISOM to further develop manufacturing processes and to scale up production.

### END

ELSE PRESS RELEASES FROM THIS DATE:

New commitments to save women and children

2011-05-20

GENEVA, 19 May 2011: Today 16 countries announced new commitments to dramatically reduce maternal, newborn and child mortality, as part of the Global Strategy for Women's and Children's Health. "Political and financial support for action on women's and children's health is reaching new and encouraging heights. The commitments build on the momentum of recent months, and prove that saving the lives of the most vulnerable can attract support at the highest levels," says Ban Ki-moon, the United Nations Secretary-General, who is leading the Every Woman Every Child campaign ...

Antibody production gets confused during long-term spaceflight

2011-05-20

Bethesda, MD—The trip to Mars just got a little more difficult now that French researchers have discovered that antibodies used to fight off disease might become seriously compromised during long-term space flight. In a new report published online in the FASEB Journal (http://www.fasebj.org), the scientists show that antibodies produced in space are less effective than those produced on terra firma. The reduced effectiveness of antibodies makes astronauts more susceptible to illness, while increasing the danger posed by bacteria and viruses likely to coexist with wayfaring ...

Poll finds most americans favor increased funding for stronger food safety oversight

2011-05-20

Among likely voters surveyed across the nation, 66 percent support additional funding for the U.S. Food and Drug Administration (FDA) to carry out new responsibilities related to food safety, according to a Pew-commissioned poll released today by the bipartisan team of Hart Research and American Viewpoint. In addition, 74 percent feel it is worth a one-to-three percent increase in the cost of food to pay for new safety measures in the FDA Food Safety Modernization Act, which became law this year. Further, 70 percent of those surveyed favor food companies paying an average ...

Eliminate Dry Skin on the Controversial HCG Diet

2011-05-20

The newly approved Tiffalina's HCG Diet Safe Lotion is the first of its kind to meet the strict guidelines of the HCG Diet. According to Dr. A.T.W. Simeons, the creator of the HCG Diet Protocol, products that contain fats or oils such as lotion, liquid foundation, lip balm, etc., will hinder the rapid weight loss typically achieved on the HCG Diet. In Dr. Simeons' manuscript, Pounds and Inches Away: A New Approach to Obesity, he states that "...fats, oils, creams and ointments applied to the skin are absorbed and interfere with weight reduction by HCG just as if ...

Animal results may pave way to treating rare mitochondrial diseases in children

2011-05-20

A human drug that both prevents and cures kidney failure in mice sheds light on disabling human mitochondrial disorders, and may represent a potential treatment in people with such illnesses. "There are no effective cures for mitochondrial diseases, even in animals," said study leader Marni J. Falk, M.D., who cares for children in the Mitochondrial-Genetics Disease Clinic at The Children's Hospital of Philadelphia. "So these striking results in mice may suggest a novel therapy of direct relevance for humans." Falk and colleagues published their study online May 5 in ...

Bearing through it: How caregivers of mentally ill kin can cope

2011-05-20

This release is available in French. Montreal, May 19, 2010 – Caring for a family member with a mental illness can be a taxing experience marked by personal sacrifices and psychological problems. A new study from Concordia University, AMI-Québec and the University of British Columbia has found family caregivers can experience high levels of stress, self-blame, substance abuse and depressive symptoms – unless they refocus their priorities and lighten their load. "Being the principal caregiver to a mentally ill family member is a stressor that often creates high ...

Report outlines successes, challenges in cancer prevention efforts

2011-05-20

ATLANTA – May 19, 2011 – A new report from the American Cancer Society details cancer control efforts and outlines improvements as well as gaps in preventive behavior that contribute to cancer mortality. Increasing rates of obesity observed since the early 1980s appear to have slowed in the past decade, particularly among women and girls, but nearly one in five adolescents and about one in three adults is obese. Vaccination against the virus that causes cervical cancer is up, but smoking declines have stalled. Meanwhile, proven cancer screening tests remain underutilized, ...

Cell phone use may reduce male fertility

2011-05-20

Men who have been diagnosed with poor sperm quality and who are trying to have children should limit their cell phone use. Researchers have found that while cell phone use appears to increase the level of testosterone circulating in the body, it may also lead to low sperm quality and a decrease in fertility. "Our findings were a little bit puzzling," says Rany Shamloul, a postdoctoral fellow in the Department of Pharmacology and Toxicology and lead researcher on the project. "We were expecting to find different results, but the results we did find suggest that there ...

Eat a protein-rich breakfast to reduce food cravings, prevent overeating later, researcher finds

2011-05-20

COLUMBIA, Mo. – A University of Missouri researcher has found that eating a healthy breakfast, especially one high in protein, increases satiety and reduces hunger throughout the day. In addition, using functional magnetic resonance imaging (fMRI) the researchers found that eating a protein-rich breakfast reduces the brain signals controlling food motivation and reward-driven eating behavior. "Everyone knows that eating breakfast is important, but many people still don't make it a priority," said Heather Leidy, assistant professor in the MU Department of Nutrition and ...

Singles Dating Sites Enter a Whole New Era in the Upcoming Year: The Next Wave of Social Interaction and Relationships Has Arrived Through Online Dating Sites - Gather Dating Sites Information Here!

2011-05-20

Singles dating sites have grown so much in popularity over the past 10 years with the emergence of social networking sites. It is so much more important now to carefully research each singles dating sites before spending your hard earned money to find that special someone. There are literally hundreds of online dating sites that fill the pages of the Internet. In my many years of research I've evaluated singles dating site after singles dating site to come to one main conclusion. An online date site can have all the bells and whistles, but without a sufficient member ...

Scientists uncover the first clear evidence of air sacs in the fossilized bones of alvarezsaurian dinosaurs: the "hollow bones" which help modern day birds to fly

Alcohol makes male flies sexy

TB patients globally often incur "catastrophic costs" of up to $11,329 USD, despite many countries offering free treatment, with predominant drivers of cost being hospitalization and loss of income

Record efficiency of 18.7 percent for flexible CIGS solar cells on plastics

ELSE PRESS RELEASES FROM THIS DATE:

LAST 30 PRESS RELEASES: