On April 1, 2002, organic light-emitting diodes gain traction in the scientific community with their most practical form released at the Ames Laboratory.“Ames Laboratory scientists from the U.S. Department of Energy, in collaboration with scientists at the University of Michigan, Ann Arbor, have developed and demonstrated a new fluorescence-based chemical sensor that is more compact, versatile, and less expensive than existing technology of this type. The new sensor holds promise for myriad potential applications, such as monitoring oxygen, inorganic gases, volatile organic compounds, biochemical compounds, and biological organisms." (Johnston). The Ames Laboratory has been a driving force in OLED research and has finally produced an effective model. Generally OLEDs have a layer of organic materials placed between an anode and a cathode, all deposited on a substrate. In the organic layer there is an emissive layer, which easily emits the electrons, and a conductive layer, to which the electrons are removed. OLEDs work via electrophosphorescence and therefore have a similar process to the one we talked about; a voltage excites a species, which transfers to a different spin orbital and then drops to the ground state to emit a photon. First, a voltage is applied across the OLED causing a current of electrons to flow from the cathode to the anode and through the organic layer. The cathode transfers electrons to the emissive layer of organic molecules. The anode removes electrons from the conductive layer of organic molecules, creating "holes" or empty spaces. At the border between the emissive and conductive layers, the electrons find "holes". The electrons fill the gaps by falling into a different spin state, corresponding to the atom missing an electron. The electron then... in the center of the paper... Optical sensors and multi-sensor arrays containing thin film electroluminescent devices. Iowa State University Research Foundation, Inc., assignee. US Patent 6,331,438 B1. December 18, 2001. Print.Freudenrich, Craig. “How things work “How OLEDs work” “How things work “Electronics” How things work. Network. 28 November 2011. "Technologies of the future". Michigan State University. Est. 1855. East Lansing, Michigan, United States. Michigan State University. Network. November 27, 2011. .Johnston, Saren. “New standard in sensor technology.” EurekAlert! - Scientific news. Ames Laboratory. Network. November 29, 2011. “Low-Cost OLED Sensors for 24/7 Protection.” Ameslab.gov. Iowa State University. Network. November 27. 2011. .