OFETs transistors

At the same time, the fibrous OFET transistors that used ribbon or sheet as substrate were successfully used to realize electronic circuits. Bonderover and Wagner (2004)... 

A series of copolymer between dithienylvinylene and phthalimide (P17 in Table 17.3) is reported by Kim et al. (2013). For this series of polymers, the electron withdrawing phthalimide is inserted into the polythiophene backbone. Both polymers display a melt-like thermal transition at 260 °C and 293 °C, respectively and no LC mesophase is observed. The HOMO and LUMO energy levels of the polymers are determined to be —5.2 and —3.3 eV, respectively. Both polymers exhibit ambipolar charge transport behaviour in the OFET transistor device. For P17a, the best hole mobility (pi,) of 0.75 cm is obtained after... 

OFETs constructed on a silicon wafer do not lake advantage of one of the main interest of organic materials, namely the possibility of building electronic devices on plastic substrates. A second important drawback of the silicon-based structure is the difficulty to individually address the gale of transistors built on the same wafer, which would prevent the achievement of integrated circuits. 

More recently. Gamier and coworkers used a printing technique to make OFETs on polymeric substrates [61]. Although printable field-effect transistors based on inorganic semiconductors have been reported as early as 1967 ]62], they did not come to any commercial development. We note, however, that in Gar-nier s device only the electrodes were actually printed. 

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]. 

For an OFET, the dependence of the drain current / on the source-drain voltage Vd and the source-gate voltage Vb is described hy the classical equations derived from inorganic-hased thin him transistors (Horowitz, 1998) ... 

When a third electrode is added to the structure shown in Fig. 8.12a, below the substrate, it creates an electric field in the insulating substrate, which is perpendicular to the path of the current between the two contacts to the selective layer. Such a structure became known as the Organic Field-Effect Transistor (OFET). It is discussed here and not in Chapter 6 because it belongs to the family of organic chemiresistors. 

The meso-functionalized bis(thien-2-yl)methanes 267 (X=S) and bis(furan-2-yl)methanes 267 (X=0) were used for synthesizing the first neutral meso-functionalized tetrathia[22]annulene derivatives 271 (X=S) and tetraoxa[22]annulene derivatives 271 (X=0) (Scheme 105). The compounds were tested for organic field effect transistor (OFET) studies and have shown good mobilities with p-type semiconductor behavior (11JCS(CC)905,12JCS(CC)121). 

The field known as organic or plastic electronics is centered on field effect transistor (FET)-based circuits mounted on large-area and/or flexible substrates. When the semiconductor is organic, the device is referred to as an organic field-effect transistor (OFET). Work on OFET has been extensively reviewed, most notably and comprehensively in Chemistry of Materials and Journal of Materials Research special issues, to which the one of us has contributed three articles [1-3]. 

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. 

Basics of Organic Field Effect Transistors (OFETs). 278... 

M = Tb, Lu) into organic thin-film transistors by LB technique and reported their field effect mobility, which represented the first report for p-type OFETs based on bis(phthalocyaninato) rare earth complexes prepared via LB method [88], Due to the highly ordered molecular arrangement of M(Pc)[Pc(OC8Hi7)g] (M = Tb, Lu) in LB films and the appropriate HOMO energy level of these double-deckers relative to the Au source-drain electrodes, the OFETs reported in that work exhibited higher hole transfer mobility of 1.7 x 10-3 cm2 V-1 s-1 in comparison with those fabricated from monomeric phthalocyanine LB films. 

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