Organic Field-effect Transistor - Materials

Materials

One common feature of OFET materials is the inclusion of an aromatic or otherwise conjugated π-electron system, facilitating the delocalization of orbital wavefunctions. Electron withdrawing groups or donating groups can be attached that facilitate hole or electron transport.

OFETs employing many aromatic and conjugated materials as the active semiconducting layer have been reported, including small molecules such as rubrene, tetracene, pentacene, diindenoperylene, perylenediimides, tetracyanoquinodimethane (TCNQ), and polymers such as polythiophenes (especially poly 3-hexylthiophene (P3HT)), polyfluorene, polydiacetylene, poly 2,5-thienylene vinylene, poly p-phenylene vinylene (PPV).

The field is very active, with newly synthesized and tested compounds reported weekly in prominent research journals. Many review articles exist documenting the development of these materials.

Rubrene-based OFETs show the highest carrier mobility 20–40 cm2/(V·s). Another popular OFET material is pentacene, which has been used since 1980s, but resulted in about 10 times lower mobilities than rubrene. The major problem with pentacene, as well as many other organic conductors, is its rapid oxidation in air to form pentacene-quinone. However if the pentacene is preoxidized, and the thus formed pentacene-quinone is used as the gate insulator, then the mobility can approach the rubrene values. This pentacene oxidation technique is akin to the silicon oxidation used in the silicon electronics.

Polycrystalline tetrathiafulvalene and its analogues result in mobilities in the range 0.1–1.4 cm2/(V·s). However, the mobility exceeds 10 cm2/(V·s) in solution-grown or vapor-transport-grown single crystalline hexamethylene-tetrathiafulvalene (HMTTF). The ON/OFF voltage is different for devices grown by those two techniques, presumably due to the higher processing temperatures using in the vapor transport grows.

All the above-mentioned devices are based on p-type conductivity. N-type OFETs are yet poorly developed. They are usually based on perylenediimides or fullerenes or their derivatives, and show electron mobilities below 2 cm2/(V·s).

Read more about this topic:  Organic Field-effect Transistor

Other articles related to "materials, material":

Organic Field-effect Transistor - History of OFETs
... However, rising costs of materials and manufacturing, as well as public interest in more environmentally friendly electronics materials have supported development of organic based electronics in more ... transistor (TFT) model, which allows the devices to use less conductive materials in their design ...
Obscene Publications Act 1959 - Impact and Assessment
... operations where the police purchased "obscene" materials were not considered sufficient evidence of publication, since the police were not considered easy to "corrupt" due to their ... Secondly, the offer of such materials for sale was not held to be publication, since it was merely an invitation to treat ... of "possessing obscene articles for publication or sale" and also extended "obscene materials" to cover photograph negatives ...
Wide Bandgap Semiconductors - Material Properties - Bandgap
... The magnitude of the coulombic potential determines the bandgap of a material, and the size of atoms and electronegativities are two factors that ... Materials with small atoms and strong, electronegative atomic bonds are associated with wide bandgaps ... high on the periodic table are more likely to be wide bandgap materials ...
Drill Bit - Characteristics - Materials
... Many different materials are used for or on drill bits, depending on the required application ... Many hard materials, such as carbides, are much more brittle than steel, and are far more subject to breaking, particularly if the drill is not held at a very ... durable than low-carbon steel bits due to the properties conferred by hardening and tempering the material ...
Bow (music) - Materials and Manufacture
... of a specially shaped stick with other material forming a ribbon stretched between its ends, which is used to stroke the string and create sound ... Part of the bowmaker's skill is the ability to choose high quality material for the stick ... treaty, so makers are currently adopting other materials woods such as Ipê (Tabebuia) as well as synthetic materials ...

Famous quotes containing the word materials:

    Artists, whatever their medium, make selections from the abounding materials of life, and organize these selections into works that are under the control of the artist.... In relation to the inclusiveness and literally endless intricacy of life, art is arbitrary, symbolic and abstracted. That is its value and the source of its own kind of order and coherence.
    Jane Jacobs (b. 1916)

    Though the hen should sit all day, she could lay only one egg, and, besides, would not have picked up materials for another.
    Henry David Thoreau (1817–1862)

    If our entertainment culture seems debased and unsatisfying, the hope is that our children will create something of greater worth. But it is as if we expect them to create out of nothing, like God, for the encouragement of creativity is in the popular mind, opposed to instruction. There is little sense that creativity must grow out of tradition, even when it is critical of that tradition, and children are scarcely being given the materials on which their creativity could work
    C. John Sommerville (20th century)