Conductive polymers are organic polymer semiconductors. An organic compound is any member of a large class of chemical compounds whose molecules contain carbon, with exception of carbides, carbonates, carbon oxides and gases containing carbon. ... A polymer is a generic term used to describe a substantially long molecule. ... A semiconductor is a material with an electrical conductivity that is intermediate between that of an insulator and a conductor. ...

For a history of the field, see: "An Overview of the First Half-Century of Molecular Electronics" by Noel S. Hush, Ann. N.Y. Acad. Sci. 1006: 1–20 (2003).

Most commercially produced organic polymers are electrical insulators. Conductive polymers, which are almost always organic, have extended delocalized bonds (often comprised of aromatic units) that creates a band structure similar to silicon, but with localized states. When charge carriers (from the addition or removal of electrons) are introduced into the conduction or valence bands (see below) the electrical conductivity increases dramatically. Technically almost all known conductive polymers are semiconductors due to the band structure, however so-called zero band gap conductive polymers may behave like metals. The most notable difference between conductive polymers and inorganic semiconductors is the mobility which, until very recently, was dramatically lower in conductive polymers than their inorganic counterparts, though recent advancements in self assembly are closing that gap. An organic compound is any member of a large class of chemical compounds whose molecules contain carbon, with exception of carbides, carbonates, carbon oxides and gases containing carbon. ... A polymer is a long, repeating chain of atoms, formed through the linkage of many molecules called monomers. ... Insulators are materials which prevent the flow of heat (thermal insulators) or electric charge (electrical insulators). ... An organic compound is any member of a large class of chemical compounds whose molecules contain carbon, with exception of carbides, carbonates, carbon oxides and gases containing carbon. ... A chemically conjugated system is a system of atoms covalently bonded with alternating single and double bonds (e. ... In chemistry, an aromatic molecule is one in which electrons are free to cycle around circular arrangements of atoms, which are alternately singly and doubly bonded to one another. ... General Name, Symbol, Number silicon, Si, 14 Chemical series metalloids Group, Period, Block 14, 3, p Appearance dark gray, bluish tinge Atomic mass 28. ... Charge carrier denotes in physics a free (mobile, unbound) particle carrying an electric charge. ... Properties The electron (also called negatron, commonly represented as e−) is a subatomic particle. ... Electrical conductivity is a measure of how well a material accommodates the transport of electric charge. ... A semiconductor is a material with an electrical conductivity that is intermediate between that of an insulator and a conductor. ... In solid state physics and related applied fields, the band gap is the energy difference between the top of the valence band and the bottom of the conduction band in insulators and semiconductors. ... Hot metal work from a blacksmith In chemistry, a metal (Greek: Metallon) is an element that readily forms ions (cations) and has metallic bonds, and metals are sometimes described as a lattice of positive ions (cations) in a cloud of electrons. ... A semiconductor is a material that is an insulator at very low temperature, but which has a sizable electrical conductivity at room temperature. ... In physics, electron mobility (or simply, mobility), is used to describe the relation between drift velocity of electrons or holes in a solid material or electrons/ions in a gas, and an applied electric field. ... Inorganic chemistry is the branch of chemistry concerned with the properties and reactions of inorganic compounds. ... Self-assembly is the fundamental principle which generates structural organization on all scales from molecules to galaxies. ...

Delocalization can be accomplished by forming a conjugated backbone of continuous overlapping orbitals, for example, alternating single and double carbon-carbon bonds, which leaves a continuous path of overlapping p orbitals. In polyacetylene, but not in most other conductive polymers, this continuous string of orbitals creates degeneracy in the frontier molecular orbitals (the highest occupied and unoccupied orbitals named HOMO and LUMO respectively) which leads to the filled (electron containing) and unfilled bands (valence and conduction bands respectively) that define a semiconductor. A chemically conjugated system, is a system of atoms covalently bonded with alternating single and double bonds (e. ... Electron atomic and molecular orbitals In quantum chemistry, the molecular electronic states, i. ... A chemical bond is the phenomenon of atoms being held together in molecules or crystals. ... Electron configuration is the arrangement of electrons in an atom, molecule or other body. ... In mathematics, a degenerate case is a limiting case in which a class of object changes its nature so as to belong to another, usually simpler, class. ... Electron atomic and molecular orbitals In quantum chemistry, the molecular electronic states, i. ... HOMO and LUMO are acronyms for highest occupied molecular orbital and lowest unoccupied molecular orbital, respectively. ... Properties The electron is a fundamental subatomic particle which carries a negative electric charge. ... In solids, the valence band is the highest range of electron energies where electrons are normally present at zero temperature. ... In semiconductors and insulators, the conduction band is the range of electron energy, higher than that of the valence band, sufficient to make the electrons free to accelerate under the influence of an applied electric field and thus constitute an electric current. ... A semiconductor is a material with an electrical conductivity that is intermediate between that of an insulator and a conductor. ...

However, conductive polymers generally exhibit very low conductivities. In fact, conduction in such relatively disordered matererials is mostly a function of "mobility gaps" with phonon-assisted hopping, polaron-assisted tunnelling, etc. between localized states and not band gaps as in crystalline semiconductors. Crystal (disambiguation) Insulin crystals A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions. ...

It is not until an electron is removed from the valence band (p-doping) or added to the conduction band (n-doping, which is far less common) does a conducting polymer become highly conductive. Doping (p or n) generates charge carriers which move in an electric field. Positive charges (holes) and negative charges (electrons) move to opposite electrodes. This movement of charge is what is actually responsible for electrical conductivity. A P-type semiconductor is obtained by carrying out a process of doping, that is adding a certain type of atoms to the semiconductor in order to increase the number of free (in this case positive) charges. ... An N-type semiconductor is obtained by carrying out a process of doping, that is adding a certain type of atoms to the semiconductor in order to increase the number of free (in this case negative) charge carriers. ... In semiconductor production, doping refers to the process of intentionally introducing impurities into an intrinsic semiconductor in order to change its electrical properties. ... Charge carrier denotes in physics a free (mobile, unbound) particle carrying an electric charge. ... In physics, an electric field or E-field is an effect produced by an electric charge that exerts a force on charged objects in its vicinity. ... In solid state physics, an electron hole (usually referred to simply as a hole) is the absence of an electron from the otherwise full valence band. ... Properties The electron (also called negatron, commonly represented as e−) is a subatomic particle. ...

For the history of the field, see: "An Overview of the First Half-Century of Molecular Electronics" by Noel S. Hush, Ann. N.Y. Acad. Sci. 1006: 1–20 (2003).

McGinness, Corry, and Proctor reported a high conductivity state in a polyacetylene (melanin) and the first organic electronic device. This was a voltage-controlled switch (Science, vol 183, 853-855 (1974)). Their original "gadget" is now in the Smithsonian's collection of early electronic devices. The chemistry Nobel prize in 2000 was awarded for the discovery and study of conducting polymers. Polyacetylene (PA) is conducting polymer of the rigid-rod polymer host family. ... List of Nobel Prize laureates in Chemistry from 1901 to the present day. ...

Chemistry

Common classes of organic conductive polymers include poly(acetylene)s, poly(pyrrole)s, poly(thiophene)s, poly(aniline)s, and poly(para-phenylene vinylene)s. Classically, these compounds are known as acetylene, polyaniline, etc. "blacks" or "melanins". The melanin pigment in animals is generally a mixed copolymer of polyacetylene, polypyrrole, and polyaniline. Polyacetylene (PA) is conducting polymer of the rigid-rod polymer host family. ... A Polypyrrole (PPy) is a chemical compound formed from a number of connected pyrrole ring structures. ... Polythiophene (PT) is conducting polymer of the rigid-rod polymer host family. ... Polyaniline (PANI) is a conducting polymer of the semi-flexible rod polymer family. ... Broadly, melanin is any of the polyacetylene, polyaniline, and polypyrrole blacks or their mixed copolymers. ...

Doping

In silicon semiconductors, a few of the silicon atoms are replaced by electron rich (e.g., phosphorus) or electron-poor (e.g. boron) atoms to create n-type and p-type semiconductors, respectively. Not to be confused with semiconductor doping, which involves replacing an atom in a lattice, polymers can be 'doped' by adding chemical reactants to oxidise (or sometimes reduce) the system to push electrons into the conducting orbitals within the already (potentially) conducting system. (In a silicon lattice, the system is far from conducting to begin with!) There are two primary methods of doping a conductive polymer, both through an oxidation-reduction (redox) process. The first method, chemical doping, involves exposing a polymer, such as melanin (typically a thin film), to an oxidant (typically iodine or bromine) or reductant (far less common, but typically involves alkali metals). The second is electrochemical doping in which a polymer-coated, working electrode is suspended in an electrolyte solution in which the polymer is insoluble along with separate counter and reference electrodes. An electric potential difference is created between the electrodes which causes a charge (and the appropriate counter ion from the electrolyte) to enter the polymer in the form of electron addition (n doping) or removal (p doping). This article is about the chemical element. ... General Name, Symbol, Number boron, B, 5 Chemical series metalloids Group, Period, Block 13, 2, p Appearance black/brown Atomic mass 10. ... An N-type semiconductor is obtained by carrying out a process of doping, that is adding a certain type of atoms to the semiconductor in order to increase the number of free (in this case negative) charge carriers. ... A P-type semiconductor is obtained by carrying out a process of doping, that is adding a certain type of atoms to the semiconductor in order to increase the number of free (in this case positive) charges. ... The ordinary meaning of lattice is the basis for several technical usages A cherry lattice pastry A mathematical lattice that is a type of partially ordered set. ... Redox reactions include all chemical processes in which atoms have their oxidation number (oxidation state) changed. ... Broadly, melanin is any of the polyacetylene, polyaniline, and polypyrrole blacks or their mixed copolymers. ... Thin-film optics is the branch of optics which deals with very thin structured layers of different materials. ... An oxidizing agent is a substance that oxidizes another substance in electrochemistry or redox chemical reactions in general. ... General Name, Symbol, Number iodine, I, 53 Chemical series halogens Group, Period, Block 17, 5, p Appearance violet-dark gray, lustrous Atomic mass 126. ... General Name, Symbol, Number bromine, Br, 35 Chemical series halogens Group, Period, Block 17, 4, p Appearance gas/liquid: red-brown solid: metallic luster Atomic mass 79. ... A reducing agent is a substance used in electrochemistry that reduces another substance. ... The alkali metals are a chemical series. ... Electrochemistry is the study of the electronic and electrical aspects of chemical reactions. ... An electrode is a conductor used to make contact with a nonmetallic part of a circuit (e. ... An electrolyte is a substance which dissociates free ions when dissolved (or molten), to produce an electrically conductive medium. ... A substance is soluble in a fluid if it dissolves in the fluid. ... Potential Difference most commonly refers to Voltage, which is basically like the pressure in an electric current. ... An ion is an atom or group of atoms with a net electric charge. ... An electrolyte is a substance which dissociates free ions when dissolved (or molten), to produce an electrically conductive medium. ...

The reason n doping is so much less common is that Earth's atmosphere is oxygen-rich, which creates an oxidizing environment. An electron-rich n doped polymer will react immediately with elemental oxygen to de-dope (re-oxidize to the neutral state) the polymer. Thus, chemical n doping has to be done in an environment of inert gas (e.g., argon). Electrochemical n doping is far more common in research, because it is easier to exclude oxygen from a solvent in a sealed flask; however, there are likely no commercialized n doped conductive polymers. Saturns atmosphere is made up of hydorgen, helium and methane ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... Inert is the state of doing little or nothing. ... General Name, Symbol, Number argon, Ar, 18 Chemical series noble gases Group, Period, Block 18, 3, p Appearance colorless Atomic mass 39. ... A solvent is a liquid that dissolves a solid, liquid, or gaseous solute, resulting in a solution. ... Flask is an operating system security architecture that provides flexible support for security policies. ...

Conjugation

The extended conjugation of a conductive polymer tends to give rise to fluorescence which has lead to the rapid development of polymer-based light emitting devices (OLEDs) and organic photovoltaic devices. A chemically conjugated system, is a system of atoms covalently bonded with alternating single and double bonds (e. ... Fluorescence induced by exposure to ultraviolet light in vials containing various sized Cadmium selenide (CdSe) quantum dots. ... An organic light-emitting diode (OLED) is a light-emitting diode (LED) made of semiconducting organic polymers. ... A solar cell, a form of photovoltaic cell, is a device that uses the photoelectric effect to generate electricity from light, thus generating solar power (energy). ...

Properties

The biggest advantage of conductive polymers is processibility. Conductive polymers are also plastics (which are organic polymers) and therefore can combine the mechanical properties (flexibility, toughness, elasticity, etc.) of plastics with the high electrical conductivities of a doped conjugated polymer. The term plastics covers a range of synthetic or semi-synthetic organic condensation or polymerization products that can be molded or extruded into objects or films or fibers. ... Elasticity has meanings in two different fields: In physics and mechanical engineering, the theory of elasticity describes how a solid object moves and deforms in response to external stress. ...

Physics

This increase in conductivity can also be accomplished in a field effect transistor (organic FET or OFET), or by irradiation. Strong coupling can also occur between electrons and phonons (mechanical oscillations such as heat vibrations, particles of sound) since both are constrained to travel along the polymer backbone. The field-effect transistor (FET) is a transistor that relies on an electric field to control the shape and hence the conductivity of a channel in a semiconductor material. ... An Organic Field-Effect Transistor (OFET) is a class of thin film transistors based on organic semiconductors. ... Photoconductivity is an optical and electrical phenomenon in which a material becomes more conductive due to the absorption of electro-magnetic radiation such as visible light, ultraviolet light, or gamma radiation. ... Generally, coupling means a mechanical connection between two things. ... A phonon is a quantized mode of vibration occurring in a rigid crystal lattice, such as the atomic lattice of a solid. ...

Applications

In some cases, light emission is observed when a voltage is applied to a thin layer of a conductive organic polymer film. It has led to the development of flat panel displays using OLEDs, solar panels and optical amplifiers. This article may be too technical for most readers to understand. ... Flat panel displays encompass a growing number of technologies enabling video displays that are lighter and much thinner than traditional television and video displays using cathode ray tubes, usually less than 10 cm (4 inches) thick. ... An organic light-emitting diode (OLED) is a light-emitting diode (LED) made of semiconducting organic polymers. ... Solar Panel (photovoltaic array) A laundromat in California powered by solar panels on the roof. ... For guitar amplifier, go to Instrument amplifier An amplifier can be considered to be any device that uses a small amount of energy to control a larger amount, although the term today usually refers to an electronic amplifier. ...

Conductive polymers are present in most mammal tissues where electrical conduction or transduction from light or sound are necessary, including the skin, eye, inner ear, and brain. Its electronic conductivity seems to be the underlying mechanism for absorption of light, and electron-phonon interactions are exploited in hearing [1]. See the main article: Melanin. Biological tissue is a substance made up of cells that perform a similar function. ... The word transduction has several meanings: In developmental psychology, transduction is reasoning from specific cases to specific cases, typically employed by children. ... Prism splitting light Light is electromagnetic radiation with a wavelength that is visible to the eye (visible light) or, in a technical or scientific setting, electromagnetic radiation of any wavelength. ... A schematic representation of hearing. ... Model of the layers of human skin In zootomy and dermatology, skin is an organ of the integumentary system; which is composed of a layer of tissues that protect underlying muscles and organs. ... This article needs to be cleaned up to conform to a higher standard of quality. ... An ear is an organ used by an animal to detect sound waves. ... Please help to figure out license type for the image Comparative brain sizes. For other articles about other subjects named brain see brain (disambiguation). ... Broadly, melanin is any of the polyacetylene, polyaniline, and polypyrrole blacks or their mixed copolymers. ...

See also

• Organic semiconductor