Organic Semiconductors

By: Troy StuartMEEN 3344

What exactly is it?• An organic semi-conductor is an

organic material that demonstrates an unusually high conductivity along with many other characteristics of semiconductors.

• This conductivity shown is often enhanced when certain gases are present.

• Organic semi-conductors include organic dyes, aromatic compounds, polymers with conjugated bonds, charge-transfer molecular complexes, and ion radical salts.

History• The first discovery of organic semi-

conductors was in 1977 (chemically doped polyacetylene).

• Before the 1977 discovery inorganic semi-conductors and metals were the basis of the semiconducting world.

• At the beginning, the stability and performance of these materials were extremely poor, however many improvements have been made in the processing of new classes of molecular materials and synthesis.

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Inorganic vs. organic semi-conductors Inorganic semi-conductors:Free carriers in form of electrons and holesWannier-Mott type exitons (small binding energies)Much smaller effective mass of carriers of that in organic.Higher mobility for charge transport.Band mechanism for charge transport

Organic semi-conductorsDo not support free electrons and holesFrenkel type exitons (large binding energies)Much larger effective mass of carriers of that in inorganic.Lower mobility for charge transport.Hopping mechanism for charge transport.

What are they used for?• Used as photosensitive materials in such objects used for information

recording processes. • Ion-radical salts are used to provide a starting point for developing

superconductors. • Also used in microelectronics and the building of different types of

sensing units. • Investigation of this material helps understand the conversion and

transfer of energy in complex physiochemical systems. • Printable electronics.

References• http://encyclopedia2.thefreedictionary.com/Organic+Semiconductor• http://en.wikipedia.org/wiki/Organic_semiconductor• http://www.eetimes.com/electronics-news/4200211/Low-cost-organic-semiconductors-said-to-rival-silic

on• http://www.iue.tuwien.ac.at/phd/li/node9.html• http://www.useoul.edu/research/highlights?bbsidx=72255&page=17• Bernards, Owens, Malliaras, Organic Semiconductors in Sensor Applications • http://www.google.com/imgres?num=10&um=1&hl=en&biw=1366&bih=677&tbm=isch&tbnid=HlZ2G2

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