The research, which could lead to a brighter polarized light source for LEDs in laptop computers, cell phones and other consumer electronics devices, currently appears in the advance online edition of the journal Nature Nanotechnology.
The research was conducted by UCLA professors of chemistry and California NanoSystems Institute members Sarah Tolbert and Benjamin J. Schwartz, and colleagues, including Hirokatsu Miyata, a research scientist with Canon’s Nanocomposite Research division in Japan. The research is federally funded by the National Science Foundation and the Office of Naval Research and privately funded by Canon.
The researchers have succeeded in taking semiconducting polymers — plastics that consist of long chains of atoms that work as semiconductors — and stretching them out in a silica (glass) host matrix so that they have new optical properties.
“If you have polymer chains that can wiggle like spaghetti, it’s hard to make them all point in the same direction,” Tolbert said. “What we do is take tiny, nanometer-sized holes in a piece of glass and force the polymer chains into the holes. The holes are so small that the spaghetti chains have no space to coil up. They have to lie straight, and all the chains end up pointing in the same direction.”
Because the chains point in the same direction, they absorb polarized light and give off polarized light. Lining up the polymer chains also provides advantages for laser technology, because all the chains can participate in the lasing process, and they can make the light polarized without the need for any external optical elements, Tolbert said.
As a postdoctoral fellow, Schwartz was one of the original discoverers in the 1990s that lasers could be made out of randomly oriented semiconducting polymer chains.
“Our new materials exploit the fact that the polymer chains are all lined up to make them into lasers that function very differently from lasers made out of random polymers,” Schwartz said.
The manner in which the polymer chains incorporate into the porous glass of the silica matrix helps to confine the light in the material, enhancing the lasing process by producing what is known as a “graded-index waveguide.” In most lasers, confining the light is typically done with external mirrors.
“Our materials don’t need mirrors to function as lasers, because the material that’s lasing is also serving to confine the light,” Schwartz said.
In combination, the alignment of the polymer chains and the confinement of the light make it 20 times easier for the new materials to lase than if a randomly oriented polymer sample were used. And because polymers can be dissolved easily in solvents, they are inexpensive to process. The glass host matrix with the aligned nanoscale pores is also inexpensive to produce.
“Usually polarized and cheap don’t go together,” Tolbert said.
The research opens the possibility of additional applications for the new materials as a brighter polarized source for displays in products with LED-type displays, including cell phones, laptops and Palm Pilots.
“If you take an inexpensive light source with which you could excite the aligned polymer chains and get the chains to reemit, you potentially have a more efficient way to generate polarized light.” Tolbert said. “This would allow displays to be brighter with less power consumption, and you could get longer battery life.”
Tolbert has collaborated with Canon for years on the development of this class of new materials.
Stuart Wolpert | EurekAlert!
Custom sequences for polymers using visible light
22.03.2018 | Tokyo Metropolitan University
The search for dark matter widens
21.03.2018 | American Institute of Physics
An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.
The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.
In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...
19.03.2018 | Event News
16.03.2018 | Event News
13.03.2018 | Event News
22.03.2018 | Trade Fair News
22.03.2018 | Earth Sciences
22.03.2018 | Earth Sciences