Ames Laboratory scientists have discovered new ways of using a well-known polymer in organic light emitting diodes (OLEDs), which could eliminate the need for an increasingly problematic and breakable metal-oxide used in screen displays in computers, televisions, and cell phones.

The metal-oxide, indium tin oxide (ITO), is a transparent conductor used as the anode for flat screen displays, and has been the standard for decades. Due to indium's limited supply, increasing cost and the increasing demand for its use in screen and lighting technologies, the U.S. Department of Energy has designated indium as "near-critical" in its assessment of materials vital to clean energy technology. Scientists have been working to find an energy efficient, cost effective substitute.

Ames Lab researcher Min Cai prepares a metal-oxide OLED.

“There are not many materials that are both transparent and electrically conductive,” said Joseph Shinar, an Ames Laboratory senior scientist. “One hundred percent of commercial display devices in the world use ITO as the transparent conducting electrode. There’s been a big push for many years to find alternatives.” “Everybody is trying to find a replacement for ITO, many working with zinc oxide, another metal oxide. But here we are working towards something different, developing ways to use a conducting polymer,” said Min Cai, a post-doctoral research scientist in the Ames Laboratory and the Dept. of Physics and Astronomy at Iowa State University. The polymer’s name is a mouthful of a word: poly (3,4-ethylene dioxythiophene):poly(styrene sulfonate), known as PEDOT:PSS for short, and has been around for about 15 years. Until recently, the material wasn’t sufficiently conductive or transparent enough to be a viable ITO substitute, Shinar said. But by using a multi-layering technique and special treatments, Cai and his fellow scientists were able to fabricate PEDOT:PSS OLEDs with vastly improved properties.   “Compared to an ITO anode device, the PEDOT:PSS device is at least 44 percent more efficient,” said Cai. According to Joe Shinar, that gain in efficiency over ITO-based technology is the highest yet recorded. The researchers used computer simulations to show that the enhanced performance is largely an effect of the difference in the optical properties between the polymer- and ITO-based devices. Another key property of PEDOT:PSS is flexibility; using ITO in OLEDs defeats one of OLED’s big pluses compared to conventional LED technology.  “OLEDs can be made on a flexible substrate, which is one of their principal advantages over LEDs. But ITO is ceramic in nature; it is brittle rather than flexible,” said Ruth Shinar, a senior scientist at Iowa State University’s Microelectronics Research Center.

The findings, co-authored by Joseph Shinar and Ruth Shinar along with Min Cai, Zhuo Ye, Teng Xiao, Rui Liu, Ying Chen, Robert W. Mayer, Rana Biswas, and Kai-Ming Ho, were recently published in Advanced Materials, one of the most prominent journals in materials science and engineering.

The research builds on continuing work to find more affordable and efficient manufacturing materials and processes for OLED manufacturing. An earlier paper published in Advanced Materials by Joseph Shinar and Ruth Shinar along with Min Cai , Teng Xiao , Emily Hellerich , and Ying Chen demonstrated the use of solution processing for small molecule-based OLEDs, which are typically constructed using a more expensive thermal evaporation deposition process.

The scientists’ ongoing investigations into better materials and processes pave the way to more cost-efficient manufacturing and making OLED technology more widely available to consumers. Joseph Shinar said that OLED televisions were already available to a limited high-end consumer, and that prices would come down as major manufacturers perfected their production processes. Both Samsung and LG exhibited a 55-inch OLED TV as a highlight feature of the 2012 Consumer Electronics Show in Las Vegas in January. “We are already getting there with OLED televisions. Consumers will see them getting more affordable and more widely available in the very near future,” said Joseph Shinar. Shinar said the technology was also beginning to be used in lighting, in applications where diffuse light is preferred instead of point source lighting, and in architectural and art design.

(l-r) Joseph Shinar, Min Cai, and Ruth Shinar.

Contacts:                                                                       For Release: Nov. 29, 2012
Joseph Shinar, Ames Laboratory, 515-294-8706
Laura Millsaps, Public Affairs, 515-294-3474

Scientists at the U.S. Department of Energy’s (DOE) Ames Laboratory have discovered new ways of using a well-known polymer in organic light emitting diodes (OLEDs), which could eliminate the need for an increasingly problematic and breakable metal-oxide used in screen displays in computers, televisions, and cell phones.

The metal-oxide, indium tin oxide (ITO), is a transparent conductor used as the anode for flat screen displays, and has been the standard for decades. Due to indium's limited supply, increasing cost and the increasing demand for its use in screen and lighting technologies, the U.S. Department of Energy has designated indium as "near-critical" in its assessment of materials vital to clean energy technology. Scientists have been working to find an energy efficient, cost effective substitute.

Ames Lab researcher Min Cai prepares a metal-oxide OLED.

“There are not many materials that are both transparent and electrically conductive,” said Joseph Shinar, an Ames Laboratory Senior Scientist. “One hundred percent of commercial display devices in the world use ITO as the transparent conducting electrode. There’s been a big push for many years to find alternatives.” “Everybody is trying to find a replacement for ITO, many working with zinc oxide, another metal oxide. But here we are working towards something different, developing ways to use a conducting polymer,” said Min Cai, a post-doctoral research scientist in the Ames Laboratory and the Dept. of Physics and Astronomy at Iowa State University. The polymer’s name is a mouthful of a word: poly (3,4-ethylene dioxythiophene):poly(styrene sulfonate), known as PEDOT:PSS for short, and has been around for about 15 years. Until recently, the material wasn’t sufficiently conductive or transparent enough to be a viable ITO substitute, Shinar said. But by using a multi-layering technique and special treatments, Cai and his fellow scientists were able to fabricate PEDOT:PSS OLEDs with vastly improved properties.   “Compared to an ITO anode device, the PEDOT:PSS device is at least 44 percent more efficient,” said Cai. According to Joe

Shinar, that gain in efficiency over ITO-based technology is the highest yet recorded.

The researchers used computer simulations to show that the enhanced performance is largely an effect of the difference in the optical properties between the polymer- and ITO-based devices.

Another key property of PEDOT:PSS is flexibility; using ITO in OLEDs defeats one of OLED’s big pluses compared to conventional LED technology.

 “OLEDs can be made on a flexible substrate, which is one of their principal advantages over LEDs. But ITO is ceramic in nature; it is brittle rather than flexible,” said Ruth Shinar, a Senior Scientist at Iowa State University’s Microelectronics Research Center.

The findings, co-authored by Joseph Shinar and Ruth Shinar along with Min Cai, Zhuo Ye, Teng Xiao, Rui Liu, Ying Chen, Robert W. Mayer, Rana Biswas, and Kai-Ming Ho, were recently published in Advanced Materials, one of the most prominent journals in materials science and engineering.

The research builds on continuing work to find more affordable and efficient manufacturing materials and processes for OLED manufacturing. An earlier paper published in Advanced Materials by Joseph Shinar and Ruth Shinar along with Min Cai , Teng Xiao , Emily Hellerich , and Ying Chen  demonstrated the use of solution processing for small molecule-based OLEDs, which are typically constructed using a more expensive thermal evaporation deposition process.

The scientists’ ongoing investigations into better materials and processes pave the way to more cost-efficient manufacturing and making OLED technology more widely available to consumers.

Joseph Shinar said that OLED televisions were already available to a limited high-end consumer, and that prices would come down as major manufacturers perfected their production processes. Both Samsung and LG exhibited a 55-inch OLED TV as a highlight feature of the 2012 Consumer Electronics Show in Las Vegas in January. “We are already getting there with OLED televisions. Consumers will see them getting more affordable and more widely available in the very near future,” said Joseph Shinar. Shinar said the technology was also beginning to be used in lighting, in applications where diffuse light is preferred instead of point source lighting, and in architectural and art design.

(l-r) Joseph Shinar, Min Cai, and Ruth Shinar.

The research is supported by the U.S. Department of Energy’s Office of Science.  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 the Office of Science website at science.energy.gov/.

The Ames Laboratory is a U.S. Department of Energy Office of Science national laboratory operated by Iowa State University. The Ames Laboratory creates innovative materials, technologies and energy solutions. We use our expertise, unique capabilities and interdisciplinary collaborations to solve global problems.

Preliminary schematic design                                 

Plans are progressing for the Sensitive Instrument Facility (SIF) even though not all of the required funding for the project has been secured. According to Ames Laboratory facilities engineer Steve Carter, the plans, and hopefully the funding, should be finalized by February which will allow the project to be bid with construction tentatively slated for Spring 2013.

“We’ve been meeting with the design team every two weeks and have the basic schematic locked in,” Carter said. “Our goal is to have construction documents ready by Feb. 1 and hopefully start on the building by mid-May,” adding that construction would take the better part of a year to complete.

The facility will be a straight-forward, rectangular-shaped building, but its rather plain exterior design belies the complexity of creating interior space isolated from the slightest vibrations or electromagnetic interference. It will have six bays to house sensitive instruments such as transmission electron microscopes.

“Isolation is key and we’re trying to design it to accommodate the next generation of instruments,” Carter said. “We’re talking about instruments so sensitive that the operator will work from a separate control room because the beating of their heart or breathing will cause excess vibration. It’s a very unique and complex building.”

For example, the concrete floors will be approximately two feet thick with vibration dampening layers built in. Similarly, the walls and ceilings will be thick concrete and the instrument bays will be lined with quarter-inch-thick aluminum plate to help create an electro-magnetic barrier. Reinforcing bars in the concrete must be fiberglass, not steel.  Likewise, the electrical conduit and even the fasteners used must be non-magnetic. And the heating and ventilation system must keep the temperature and humidity constant without creating vibration or interference.

“We have an absolute limit of $10 million for the project,” Carter said, “so we’ve been working very hard to ensure it meets those budget constraints. It’s also why we’ve put extra time into developing the schematics.”

“There’s been good input from a lot of players, including Alex King, the microscopy group, and ISU Facilities Planning and Management staff,” he said. “And (facilities manager) Mark Grootveld deserves a lot of credit for guiding the overall project.”

The building is slated to be built near the Applied Science Center II site north of Ontario Road in west Ames.

While the SIF is the main project, it’s not the only facilities project in the works. With a recent warm-up, the steps on the north side of Wilhelm Hall have been repaired. The project (pictured left) included cleaning and resetting the stonework, and caulking the joints to prevent water infiltration.

Work is continuing on the renovation of the heating, ventilation and air conditioning system in Spedding Hall. Carter said that while funding for that project has been substantially reduced, work will continue but the time frame will be stretched out.  He praised occupants in the building for their “excellent cooperation,” particularly during the unplanned replacement of the building’s main drain line.

Other recently completed projects include tuck pointing and continued access control work on Spedding Hall, and finalization of some warranty work on the Spedding Auditorium.

Contacts:                                                                              For release: Nov. 27, 2012

Tom Barton, Chemistry and Ames Laboratory, 515-294-7655
Steve Karsjen, Ames Laboratory, 515-294-5643
Mike Krapfl, News Service, 515-294-4917

AMES, Iowa – Tom Barton, a chemist with long ties to Iowa State University and the U.S. Department of Energy’s Ames Laboratory, has been elected president-elect of the American Chemical Society.

The American Chemical Society (ACS) has more than 164,000 members and is the world’s largest scientific society.

Barton will be the society’s president-elect in 2013, its president in 2014 and its immediate past-president in 2015. He was recently elected with 62 percent of the vote.

Barton is currently an Iowa State Distinguished Professor Emeritus of Chemistry and an associate of the Ames Laboratory. He has been at Iowa State since 1967 and a distinguished professor since 1984. He directed the Ames Laboratory from 1988 to 2007. He directed Iowa State’s Institute for Physical Research and Technology from 1998 to 2007. He was also interim director of the Iowa Energy Center in 2009. He retired from Iowa State in May 2012.

And why does he want to lead the ACS? These, after all, are difficult times for chemistry. Jobs are being outsourced, unemployment of chemists is high, research funding is uncertain and young people are less interested in the field. The ACS has developed plans and strategies to address those issues.

“However,” Barton wrote on his candidate website, “plans remain only words unless there is leadership who passionately believes in our mission, and has the background, talents, capabilities and time available to lead the effort to carry out these strategies, to sell these strategies and to energize the membership of ACS to carry them out with zeal.”

Barton said his priorities will be improving elementary and secondary science education in America, boosting the public’s appreciation of chemistry and addressing employment and globalization issues.

About American education, he said, “Everybody knows that in K-12 we’re not doing a good job in science, technology, engineering and math. We have more conferences and special reports but still do little or nothing. We need drastic changes. I hope this new bully pulpit of mine will add to the efforts in getting this done.”

Barton, who’s not shy about sharing an opinion or telling a story (he’s even writing some fiction these days), said it’s purely an accident that he’s a chemist.

He started college on a music scholarship – half voice and half clarinet – and was asked to pick a science class to meet his degree requirements. When a college official tried to steer him away from a chemistry class for science students, Barton rose to the challenge and took the harder course.

“The next thing you know I had a Ph.D. in chemistry,” he said.

And now, instead of settling into retirement, he’s preparing to advance chemistry and meet the changing needs of chemists.

“While the ACS president is only one person,” Barton wrote on his website, “an energetic, experienced president can lead by coordinating the effort of 164,000 bright, well-educated members and their collective wisdom to take us into the future.”

Tom Barton, retired Ames Laboratory Director and a chemist with long ties to Iowa State University, has been elected president-elect of the American Chemical Society.

The American Chemical Society (ACS) has more than 164,000 members and is the world’s largest scientific society.

Barton will be the society’s president-elect in 2013, its president in 2014 and its immediate past-president in 2015. He was recently elected with 62 percent of the vote.

Barton is currently an Iowa State Distinguished Professor Emeritus of Chemistry and an associate of the Ames Laboratory. He has been at Iowa State since 1967 and a distinguished professor since 1984. He directed the Ames Laboratory from 1988 to 2007. He directed Iowa State’s Institute for Physical Research and Technology from 1998 to 2007. He was also interim director of the Iowa Energy Center in 2009. He retired from Iowa State in May 2012.

And why does he want to lead the ACS? These, after all, are difficult times for chemistry. Jobs are being outsourced, unemployment of chemists is high, research funding is uncertain and young people are less interested in the field. The ACS has developed plans and strategies to address those issues.

“However,” Barton wrote on his candidate website, “plans remain only words unless there is leadership who passionately believes in our mission, and has the background, talents, capabilities and time available to lead the effort to carry out these strategies, to sell these strategies and to energize the membership of ACS to carry them out with zeal.”

Barton said his priorities will be improving elementary and secondary science education in America, boosting the public’s appreciation of chemistry and addressing employment and globalization issues.

About American education, he said, “Everybody knows that in K-12 we’re not doing a good job in science, technology, engineering and math. We have more conferences and special reports but still do little or nothing. We need drastic changes. I hope this new bully pulpit of mine will add to the efforts in getting this done.”

Barton, who’s not shy about sharing an opinion or telling a story (he’s even writing some fiction these days), said it’s purely an accident that he’s a chemist.

He started college on a music scholarship – half voice and half clarinet – and was asked to pick a science class to meet his degree requirements. When a college official tried to steer him away from a chemistry class for science students, Barton rose to the challenge and took the harder course.

“The next thing you know I had a Ph.D. in chemistry,” he said.

And now, instead of settling into retirement, he’s preparing to advance chemistry and meet the changing needs of chemists.

“While the ACS president is only one person,” Barton wrote on his website, “an energetic, experienced president can lead by coordinating the effort of 164,000 bright, well-educated members and their collective wisdom to take us into the future.”