Salmon garnish points the way to green electronics
Professor Andrew Steckl, a leading expert in light-emitting diodes, is intensifying the properties of LEDs by introducing biological materials, specifically salmon DNA.
Electrons move constantly 鈥� think of tiny particles with a negative charge and attention deficit disorder. It is through the movement of these electrons that electric current flows and light is created.
Steckl is an Ohio Eminent Scholar in UC鈥檚 Department of Electrical and Computer Engineering. He believed that if the electrons鈥� mobility could be manipulated, then new properties could be revealed.
In considering materials to introduce to affect the movement of the electrons, Steckl evaluated the source of materials with an eye to supply, especially materials that do not harm the environment.
鈥淏iological materials have many technologically important qualities 鈥� electronic, optical, structural, magnetic,鈥� says Steckl. 鈥淏ut certain materials are hard for to duplicate, such as DNA and proteins.鈥� He also wanted a source that was widely available, would not have to be mined, and was not subject to any organization or country鈥檚 monopoly. His answer?
Salmon sperm.
鈥淪almon sperm is considered a waste product of the fishing industry. It鈥檚 thrown away by the ton,鈥� says Steckl with a smile. 鈥淚t鈥檚 natural, renewable and perfectly biodegradable.鈥� While Steckl is currently using DNA from salmon, he thinks that other animal or plant sources might be equally useful. And he points out that for the United States, the green device approach takes advantage of something in which we continue to be a world leader 鈥� agriculture.
Steckl is pursuing this research in collaboration with the Air Force Research Laboratory. The research was featured recently in such premier scientific publications as the inaugural issue of Nature Photonics and on the cover of Applied 麻豆淫院ics Letters.
鈥淭he Air Force had already been working with DNA for other applications when they came to us and said, 鈥榃e know that you know how to make devices,鈥欌�� quotes Steckl. 鈥淭hey also knew that they had a good source of salmon DNA.鈥� It was a match made in heaven.
So began Steckl鈥檚 work with BioLEDs, devices that incorporate DNA thin films as electron blocking layers. Most of the devices existing today are based on inorganic materials, such as silicon. In the last decade, researchers have been exploring using naturally occurring materials in devices like diodes and transistors.
鈥淭he driving force, of course, is cost: cost to the producer, cost to the consumer and cost to the environment鈥� Steckl points out, 鈥渂ut performance has to follow.鈥�
And what a performance 鈥� lights, camera, action!
鈥淒NA has certain optical properties that make it unique,鈥� Steckl says. 鈥淚t allows improvements in one to two orders of magnitude in terms of efficiency, light, brightness 鈥� because we can trap electrons longer.鈥�
When electrons collide with oppositely charged particles, they produce very tiny packets of light called 鈥減hotons.鈥�
鈥淪ome of the electrons rushing by have a chance to say 鈥榟ello,鈥� and get that photon out before they pass out,鈥� Steckl explains. 鈥淭he more electrons we can keep around, the more photons we can generate.鈥� That鈥檚 where the DNA comes in, thanks to a bunch of salmon.
鈥淒NA serves as a barrier that affects the motion of the electrons,鈥� says Steckl. It allows Steckl and his fellow researcher, the Air Force鈥檚 Dr. James Grote, to control the brightness of the light that comes out.
鈥淭he story continues,鈥� says Steckl, again smiling. 鈥淚鈥檓 receiving salmon sperm from researchers around the world wanting to see if their sperm is good enough.鈥� The next step is to now replace some other materials that go into an LED with biomaterials. The long-term goal is be able to make 鈥済reen鈥� devices that use only natural, renewable and biodegradable materials.
Source: University of Cincinnati
