In April 1, 2002, organic light emitting diodes gain rise in the scientific community with their published, more practical form at Ames Laboratory.
“Scientists at the U.S. Department of Energy's Ames Laboratory, in collaboration with scientists at the University of Michigan, Ann Arbor, have developed and demonstrated a novel, fluorescence-based chemical sensor that is more compact, versatile and less expensive than existing technology of its kind. The new sensor holds promise for myriad potential applications, such as monitoring oxygen, inorganic gases, volatile organic compounds, biochemical compounds, and biological organisms.”(Johnston).
Ames Laboratory has been a driving force in ...view middle of the document...
The intensity of the light depends on the amount of electrical current applied: the more current, the brighter the light. This process is a unique way sensing because OLEDs can emit without a light source. Compared to conventional sensors that use lasers or inorganic light-emitting devices as light sources, which can be expensive, bulky, and hard to integrate with other components. It is these advantages that make OLEDs great as sensing tools.
The first part of sensing is placing substance in contact with a thin film above the OLED. The film contains a material that reacts in some way when it comes in contact with the test substance. The thin sensing film’s luminescence (excited by the OLED) is sensitive to the substance of interest. The OLED, powered by a small battery, provides a light source. In the presence of light, the sensing material will luminescence, emitting a specific color, which is affected by the target substance. For instance, the film may glow green normally but with a substance on it, the luminescence could change to blue. A photodetector records the luminescence and transmits the information to the control, processing, and display unit. This makes OLEDs specific to certain substances but given their size and ease of use, the specificity is negligible. (Freudenrich).
One of the biggest advantages of OLEDs is that they give an immediate response and do not need to be shipped to a lab for analysis. This property can make OLEDs useful as dosimeters, which measure exposure to something in the environment — usually to a hazard that could inflict a cumulative impact over long periods of time, or over a lifetime. Curative action could be taken immediately instead of waiting for an analysis. This sensing chemistry can be selected to detect pathogens or other analytes a person might be exposed to, and with the small OLED size, multiple hazards can be measured at once on a small chip. (Aylott).
The versatility and flexibility of OLEDs as sensors is their biggest prospect. Some proposed systems could contain up to 16x16 = 256 sensors on a single, one-square-millimeter chip. However, before developing,...