Organic field-effect transistor

In the past decade, the research on organic field-effect transistors (OFETs) has experienced remarkable progress mainly because of the development of novel OFET materials, which have allowed to reach carrier mobility values good enough to compete with amorphous silicon. 

Langmuir-Blodgett (LB) technique has been also used for the preparation of Pc-based OFET, as it allows the fine control of both the structure and the thickness of the film at the molecular level [226,227], OFET devices based on amphiphilic tris(phthalocyaninato) rare earth, triple-decker complexes have been prepared by LB technique, showing good OFET performances [228], More recently, ambipolar transport has also been realized in OFET devices through a combination of holeconducting CuPc and n-conducting Cgo fullerene, in which the asymmetry of the 

Cross-section of an OFET with bottom electrode geometry. A conductive channel is created at the interface between the p-type semiconductor and the dielectric layer when a negative bias is applied at the gate electrode. 

Prominent materials for p-type semiconductors are pentacene i or oligo-thiophenes both are commonly deposited by vacuum sublimation. To reduce production costs materials that can be processed from solution like poly(3-alkyl-thiophene) or TlPS-pentacene have gained considerable attention. 

PEDOT PSS has been applied in OFETs dominantly as printable electrode. There are, however, also reports employing the conducting polymer as interlayer to improve charge injection and as active layer. 

Metal electrodes for source, drain, and gafe in OFETs are most commonly deposited by photolithographic etching or by evaporating metals through a shadow mask to achieve small patterns with dimensions in the order of microns. To reduce manufacturing costs it is however necessary to find simpler means of deposition. Printing the materials directly onto a substrate is considered as a reliable approach. 

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A Stable Class of Low-Band-Gap Materials 24 Organic Field Effect Transistors (FETs) 25 Synthesis 26 Aldol Route 27... 

Disubstituted DTT 495 has been reported to be a organic semiconductor for organic field-effect transistors <2004SM(146)251>. 

Anthopoulos, T.D., Tanase, C., Setayesh, S., Meijer, E.J., Hummelen, J.C., Blom, P.W.M., and de Leeuw, D.M. (2004) Ambipolar organic field-effect transistors based on a solution-processed methanofuller-ene. Adv. Mater. 16(23-24), 2174-2179. 

Short intramolecular contacts between chalcogens and other chalcogens or other heteroatoms have been shown to influence molecular geometry, particularly planarity, in many structures of electroactive materials. Hence the position of the chalcogen atom in the material can profoundly affect its properties. For example Crouch et al 2 report the X-ray crystal structure of compound 24 (Figure 10), a candidate for an organic field-effect transistor, showing the effect of intramolecular S- F close contacts (in tandem with H F contacts) on the planarity of the molecule in the solid state. Note also the... 

Facchetti A, Yoon MH, Marks TJ (2005) Gate dielectrics for organic field-effect transistors new opportunities for organic electronics. Adv Mater 17(14) 1705-1725... 

Horowitz G (1998) Organic field-effect transistors. Adv Mater 10 365-377... 

As a class of n-type organic semiconductors, PBI derivatives have received considerable attention for a variety of applications [312, 313], for example, for organic or polymer light-emitting diodes (OLEDs and PLEDs) [314, 315], thin-film organic field-effect transistors (OFETs) [316, 317], solar cells [318, 319], and liquid crystals [320]. They are also interesting candidates for single-molecule device applications, such as sensors [321], molecular wires [322], or transistors [141]. 

Dimitrakopoulos, C. D. Afzali-Ardakani, A. Furman, B. Kymissis, J. Purushothaman, S. 1997. Trans-trans-2,5-bis-[2- 5-(2,2 -bithienyl) ethenyl] thiophene Synthesis, characterization, thin film deposition and fabrication of organic field-effect transistors. Synth. Met. 89 193-197. 

Wagner, V. Wobkenberg, P Hoppe, A. Seekamp, J. 2006. MHz organic field effect transistors. Proceedings of OEC-06 Peer Reviewed Papers, pp. 7. 

Manuelli, A. Knobloch, A. Bernds, A. Clemens, W. 2002. Applicability of coating techniques for the production of organic field effect transistors. 2nd International IEEE Conference on Polymers and Adhesives in Microelectronics and Photonics, POLYTRONIC 2002. pp. 201-204. 

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