Chemist developing next-generation material
Fiber optics increased the speed and quantity of information that can be transmitted through the Internet by transforming electrical signals into pulsating light.
Photo by Eric Landwehr
The thin-film material in assistant professor Cheng Zhang’s hands may be the key to making fiber-optic components for computers and other electronic devices.
The same can be done within laptops and other devices by using organic materials containing chromophore as an active compound, according to South Dakota State University materials chemist Cheng Zhang. Components made from this organic material can provide a larger bandwidth and draw less power.
Zhang began working on electro-optical chromophores while earning his doctorate at the University of Southern California. In 2000, he and chemistry professor Larry Dalton developed the first electro-optical chromophore CLD1. The ‘C’ in the name stands for Cheng, while the LD is for Larry Dalton, he explained. The material was patented by Pacific Wave Communications, LLC, and sold by Sigma Aldrich.
Zhang has continued his work on chromophore since coming to SDSU in 2011 as an assistant professor in the chemistry and biochemistry department through support from the South Dakota Board of Regents.
To create the material, chromophore—an organic compound that has color—is suspended in a soft yet tough material called a polymer, according to Zhang. A coating of this material is then typically placed on a glass or silicon substrate, much like making solar panels, and then used to make electro-optical devices, he explained. Using a polymer makes the resulting device easier to integrate with electronic circuitry.
The bipolar chromophores Zhang is developing are only 3 nanometers long--barely visible under the best electronic microscope. “The diameter of a human hair is about 20,000 times the length of a bi-polar chromophore,” he noted.
These bi-polar chromophores act like magnets. When the tiny rods get too close together, they flip and stick together, Zhang explained. An electric field is applied to align the poles in the same direction; however, the more chromophores that are loaded into the material, the more difficult this becomes.
“This fundamental problem limits the concentration of chromophore that can be loaded into the polymer,” Zhang said.
His research work seeks to solve this problem by creating a protective ring around a portion of each rod to keep them apart. This may “prevent the formation of tight aggregates even at the highest concentration,” Zhang said.
He demonstrated this on the first ring-protected chromophore, PCR1, and is applying the strategy to current state-of-the-art chromophores.
When more rods are packed into the material, a new problem has emerged, according to Zhang. The material becomes too conductive, so when the current is applied to align the dipole, the chromophores burn out and die.
To solve the new problem, Zhang has added more insulating rings. If this effort is successful, the resulting material will have a higher electro-optic activity level, which will improve the material’s performance.
According to the industry standard, electro-optical materials should be able to withstand 185 degrees Fahrenheit for 2,000 hours while maintaining at least 90 percent of the initial activity. Designing this electro-optic material involves a trade-off between its thermal stability and electro-optic activity.
“If you improve one property, the other property gets sacrificed,” he said, “but we have to come up with a novel idea to minimize the trade-off.”
About South Dakota State University
Founded in 1881, South Dakota State University is the state’s Morrill Act land-grant institution as well as its largest, most comprehensive school of higher education. SDSU confers degrees from eight different colleges representing more than 175 majors, minors and specializations. The institution also offers 29 master’s degree programs, 13 Ph.D. and two professional programs.
The work of the university is carried out on a residential campus in Brookings, at sites in Sioux Falls, Pierre and Rapid City, and through Cooperative Extension offices and Agricultural Experiment Station research sites across the state.
Cheng Zhang | newswise
Using Ultrashort Pulsed Laser Radiation to Process Fibre-Reinforced Components
25.07.2016 | Fraunhofer-Institut für Lasertechnik ILT
Added bacterial film makes new mortar resistant to water uptake
25.07.2016 | Technische Universität München
Researchers at the U.S. Department of Energy's (DOE) Ames Laboratory have discovered an unusual property of purple bronze that may point to new ways to achieve high temperature superconductivity.
While studying purple bronze, a molybdenum oxide, researchers discovered an unconventional charge density wave on its surface.
Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.
Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...
Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases
Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...
Scaffolding and specialised workers help with the delivery – Heidelberg biochemists gain new insights into biogenesis
A type of scaffolding on which specialised workers ply their trade helps in the manufacturing process of the two subunits from which the ribosome – the protein...
Scientists at the Helmholtz Zentrum München have developed a new mass spectrometry imaging method which, for the first time, makes it possible to analyze hundreds of metabolites in fixed tissue samples. Their findings, published in the journal Nature Protocols, explain the new access to metabolic information, which will offer previously unexploited potential for tissue-based research and molecular diagnostics.
In biomedical research, working with tissue samples is indispensable because it permits insights into the biological reality of patients, for example, in...
15.07.2016 | Event News
15.07.2016 | Event News
11.07.2016 | Event News
25.07.2016 | Physics and Astronomy
25.07.2016 | Materials Sciences
25.07.2016 | Materials Sciences