Organic electronics

Organic electronics is a field of materials science concerning the design, synthesis, characterization, and application of organic small molecules or polymers that show desirable electronic properties such as conductivity. Unlike conventional inorganic conductors and semiconductors, organic electronic materials are constructed from organic (carbon-based) small molecules or polymers using synthetic strategies developed in the context of organic and polymer chemistry. One of the promised benefits of organic electronics is their potential low cost compared to traditional inorganic electronics. Attractive properties of polymeric conductors include their electrical conductivity that can be varied by the concentrations of dopants. Relative to metals, they have mechanical flexibility. Some have high thermal stability. One class of materials of interest in organic electronics are electrical conductive, i.e. substances that can transmit electrical charges with low resistivity. Traditionally, conductive materials are inorganic. Classical (and still technologically dominant) conductive materials are metals such as copper and aluminum as well as many alloys. The earliest reported organic conductive material, polyaniline, was described by Henry Letheby in 1862. Work on other polymeric organic materials began in earnest in the 1960s, A high conductivity of 1 S/cm (S = Siemens) was reported in 1963 for a derivative of tetraiodopyrrole. In 1977, it was discovered that polyacetylene can be oxidized with halogens to produce conducting materials from either insulating or semiconducting materials. The 2000 Nobel Prize in Chemistry was awarded to Alan J. Heeger, Alan G. MacDiarmid, and Hideki Shirakawa jointly for their work on conductive polymers. These and many other workers identified large families of electrically conducting polymers including polythiophene, polyphenylene sulfide, and others. In the 1950s, a second class of electric conductors were discovered based on charge-transfer salts. Early examples were derivatives of polycyclic aromatic compounds. For example, pyrene was shown to form semiconducting charge-transfer complex salts with halogens. In 1972, researchers found metallic conductivity(conductivity comparable to a metal) in the charge-transfer complex TTF-TCNQ. Conductive plastics have undergone development for applications in industry. In 1987, the first organic diode was produced at Eastman Kodak by Ching W. Tang and Steven Van Slyke. The initial characterization of the basic properties of polymer light emitting diodes, demonstrating that the light emission phenomenon was injection electroluminescence and that the frequency response was sufficiently fast to permit video display applications, was reported by Bradley, Burroughes, Friend, et al. in a 1990 Nature paper. Moving from molecular to macromolecular materials solved the problems previously encountered with the long-term stability of the organic films and enabled high-quality films to be easily made. Subsequent research developed multilayer polymers and the new field of plastic electronics and organic light-emitting diodes (OLED) research and device production grew rapidly. Organic conductive materials can be grouped into two main classes: conductive polymers and conductive molecular solids and salts.