Featured Research

from universities, journals, and other organizations

Bright Idea: A New Class Of Sensors Fashioned From LED's

Date:
February 8, 2001
Source:
University Of Wisconsin-Madison
Summary:
A group of scientists at the University of Wisconsin-Madison have shed light on a valuable new use for LEDs by demonstrating their usefulness as chemical sensors. In research published in the Jan. 25 issue of the journal Nature, the UW-Madison researchers illustrate how chemical exposure can alter the surface structure of LED materials, causing the intensity of the light to fluctuate.

Madison - Already glowing away on thousands of consumer electronics products, the light-emitting diode (LED) is proving to be a remarkably versatile material.

The same technology behind the glowing lights reminding people to turn off VCRs and stereos is being applied to new treatments for hard-to-heal wounds and new super-efficient traffic lights. Now a group of scientists at the University of Wisconsin-Madison have shed light on a valuable new use for LEDs by demonstrating their usefulness as chemical sensors.

In research published in the Jan. 25 issue of the journal Nature, the UW-Madison researchers illustrate how chemical exposure can alter the surface structure of LED materials, causing the intensity of the light to fluctuate. That resulting light change can be put to use in simple, highly sensitive systems that warn of chemicals in the air or water.

The finding may have a big impact on the national campaign to develop "laboratories on a chip," by offering an accurate, inexpensive and mass-producible method to integrate sensors on to computer chips.

"There's a big movement to make sensors smaller, more versatile and to use the economy of scale you get from the semiconductor industry," says co-author Thomas Kuech, a professor of chemical engineering and materials science. "What's nice about this effort is the prospect of making very small optical emitters and detectors that are chemically sensitive to a wide range of substances you would care about in the environment."

Perhaps the most ubiquitous chemical sensors are at work in home safety systems used to detect smoke, radon or carbon monoxide. They are also used to monitor air and water pollution, both indoors and outdoors, and monitor problems in car engine performance. But the existing technology is primitive compared to the "smart environments" imagined by scientists.

Arthur Ellis, professor of chemistry and co-author of the paper, says this project is funded through a National Science Foundation initiative called "XYZ on a Chip." The essential challenge is to demonstrate how a wide range of non-electrical processes can exploit the power and sophistication of integrated chip technology. In addition to chemical sensors, the effort is being applied to genomics, chemistry, mechanics and software development.

A light-emitting diode, a tiny chip made of semiconducting materials, converts electrical energy into visible light. The chips also can convert light into electricity when used in a solar cell or photo cell. In past research, Ellis demonstrated that light emitted from these materials could be altered by exposure to chemicals.

Ellis teamed with Kuech and electrical and computer engineer Luke Mawst to apply this discovery to a new class of sensors. The group began by changing the surface of the light-emitting structure to enhance its chemical sensitivity. Then they integrated it onto a chip with a nearby detector system, where both the emitter and detector can communicate.

When they placed the system in a chemical environment, the chemicals that interacted with the semiconductor surface changed the amount of light emitted - and thus detected. But rather than just indicating the presence of that chemical, the system was also sensitive to the amount of that chemical in the air.

Mawst, co-author of the paper, says the technology's most attractive commercial potential is its simplicity. Conventional sensors are much more complex devices made from a variety of materials, whereas these are modeled from the same chunk of material and can be built with the cost-effectiveness of computer chips. These very flexible sensors could be adjusted to detect everything from ammonia in a factory environment to biological molecules in a war zone.

One ultimate goal of the "lab on a chip" research effort is to create a real-time response to environmental dangers, whether it be a chemical spill in a river or the threat of chemical warfare or bioterrorism. The current technology is nowhere near meeting that challenge, Kuech says.

Mawst says industry has shown early interest in the technology. In the next step, researchers will try to better understand the basic chemical reactions that are taking place on the surfaces of LEDs in order to optimize the process.

For more details about nanotechnology, visit: http://www.mrsec.wisc.edu/EDETC/cineplex/


Story Source:

The above story is based on materials provided by University Of Wisconsin-Madison. Note: Materials may be edited for content and length.


Cite This Page:

University Of Wisconsin-Madison. "Bright Idea: A New Class Of Sensors Fashioned From LED's." ScienceDaily. ScienceDaily, 8 February 2001. <www.sciencedaily.com/releases/2001/02/010207073749.htm>.
University Of Wisconsin-Madison. (2001, February 8). Bright Idea: A New Class Of Sensors Fashioned From LED's. ScienceDaily. Retrieved July 22, 2014 from www.sciencedaily.com/releases/2001/02/010207073749.htm
University Of Wisconsin-Madison. "Bright Idea: A New Class Of Sensors Fashioned From LED's." ScienceDaily. www.sciencedaily.com/releases/2001/02/010207073749.htm (accessed July 22, 2014).

Share This




More Matter & Energy News

Tuesday, July 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Government Approves East Coast Oil Exploration

Government Approves East Coast Oil Exploration

AP (July 18, 2014) The Obama administration approved the use of sonic cannons to discover deposits under the ocean floor by shooting sound waves 100 times louder than a jet engine through waters shared by endangered whales and turtles. (July 18) Video provided by AP
Powered by NewsLook.com
Sunken German U-Boat Clearly Visible For First Time

Sunken German U-Boat Clearly Visible For First Time

Newsy (July 18, 2014) The wreckage of the German submarine U-166 has become clearly visible for the first time since it was discovered in 2001. Video provided by Newsy
Powered by NewsLook.com
Obama: U.S. Must Have "smartest Airports, Best Power Grid"

Obama: U.S. Must Have "smartest Airports, Best Power Grid"

Reuters - US Online Video (July 17, 2014) President Barak Obama stopped by at a lunch counter in Delaware before making remarks about boosting the nation's infrastructure. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com
Crude Oil Prices Bounce Back After Falling Below $100 a Barrel

Crude Oil Prices Bounce Back After Falling Below $100 a Barrel

TheStreet (July 16, 2014) Oil Futures are bouncing back after tumbling below $100 a barrel for the first time since May yesterday. Jeff Grossman is the president of BRG Brokerage and trades at the NYMEX. Grossman tells TheStreet the Middle East is always a concern for oil traders. Oil prices were pushed down in recent weeks on Libya increasing its production. Supply disruptions in Iraq fading also contributed to prices falling. News from China's economic front showing a growth for the second quarter also calmed fears on its slowdown. Jeff Grossman talks to TheStreet's Susannah Lee on this and more on the Energy Department's Energy Information Administration (EIA) report. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins