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Benzopyrazinoisoindigo, a pigment reported 40 years ago, should be a good candidate for n-type semiconductors if the reported structure is correct. Reinvestigation of this molecule revealed that it is actually (4H,4'H)-benzopyrazinoisoindigo, which could be considered as the reduced form of benzopyrazinoisoindigo, and hence, it is a good candidate for p-type semiconductors. The route toward the synthesis of this molecule was optimized, and a mechanism was accordingly proposed. A field-effect transistor based on this material showed a hole mobility up to 2.5 ? 10-2 cm² V-1 s-1. [ABSTRACT FROM AUTHOR]

In recent years, tetrathiafulvalene (TTF) and its derivatives have been used as semiconducting materials for organic field-effect transistors (OFETs). In this review, we summarize the recent progress in the field of TTF-based OFETs. We introduce the structure and operation of OFETs, and focus on TTF derivatives used in OFETs. TTF derivatives used in OFETs can be divided into three parts by the semiconductor's morphology and the device fabrication technique: (1) TTF derivatives used for single-crystal OFETs, (2) TTF derivatives used for vacuum-deposited thin-film OFETs, and (3) TTF derivatives used for solutionprocessed thin-film OFETs. The single-crystal OFETs based on TTF derivatives were fabricated by drop-casting method and showed high performance, with the mobility up to 1.4 cm2/Vs. The vacuum-deposited thin-film OFETs based on TTF derivatives were well developed, some of which have shown high performance comparable to that of amorphous silicon, with good air-stability. Although the mobilities of most solution-processed OFETs based on TTF derivatives are limited at 10-2 cm2/Vs, the study on solution-processable TTF derivatives and their devices are promising, because of their low-cost, large-area-coverage virtues. The use of organic charge-transfer (OCT) compounds containing TTF or its derivatives in OFETs is also included in this review. [ABSTRACT FROM AUTHOR]

Organic thin-film field-effect transistors (OTFTs) are emerging as attractive candidates for low-price, large-area, and flexible circuit applications. A variety of organic compounds have been utilized as active semiconductor materials for OTFTs, among which phthalocyanine compounds have attracted considerable attention owing to their remarkable chemical and thermal stability as well as good field-effect performance. Here, we review recent results on the phthalocyanine-based OTFTs. The correlation between the crystal packing structure and the charge transport property is discussed, and we conclude with a description of the future prospects for phthalocyanine-based OTFTs. [ABSTRACT FROM AUTHOR]

We present the synthesis and characterization of a fused-ring compound, dithieno[2,3-d:2',3'-d']thieno[3,2-b:4,5-b']dithiophene (pentathienoacene, PTA). In contrast to pentacene, PTA has a larger band gap than most semiconductors used in organic field-effect transistors (OFETs) and therefore is expected to be stable in air. The large π-conjugated and planar molecular structure of PTA would also form higher molecular orders that are conductive for carrier transport. X-ray diffraction and atomic force microscopy experiments on its films show that the molecules stack in layers with their long axis upright from the surface. X-ray photoelectron spectroscopy suggests that there are no chemical bonds at the PTA/Au interlace. OFETs based on the PTA have been constructed, and their performances as p-type semiconductors are also presented. A high mobility of 0.045 cm²/V s and an on/off ratio of 10³ for a PTA OFET have been achieved, demonstrating the potential of PTA for application in future organic electronics. [ABSTRACT FROM AUTHOR]

We demonstrate modification of the indium tin oxide (ITO) surface with an ultrathin layer of hexadecafluorocopper phthalocyanine (F16CuPc) can significantly enhance hole injection as a result of the formation of an interfacial dipole layer. The dipole layer produces a surface potential shift, which reduces the hole injection energy barriers and thus improves the hole injection efficiency. The devices with anode modification exhibit significantly enhanced luminance efficiencies and dramatically decreased operation voltages, compared to devices with the bare ITO anode. The minimum turn-on voltage of 2.6 V and the maximum efficiency of 5.1 cd/A are achieved. [ABSTRACT FROM AUTHOR]

Employing 5,5′-bis-biphenyl-dithieno[3,2-b:2′,3′-d]thiophene (BPDTT) as semiconducting layer and poly(vinyl alcohol) (PVA) as gate dielectric layer, we have fabricated organic thin-film transistors. These devices exhibit excellent field-effect performances with a high mobility of up to 0.6 cm2/V s and a very low operating voltage (<1 V) at room temperature. The single crystal of BPDTT was grown and analyzed. The high performances are mainly attributed to the close herringbone packing of BPDTT molecules and the high homogeneity between PVA and BPDTT molecules. [ABSTRACT FROM AUTHOR]

Discusses the synthesis of a series of pentacoordinate substituted p-benzoate bis(8-hydroxyquinaldine) gallium complexes. Fig. 1). Characterization of the structure of complexes was characterized by element analysis; Effect of the substituted group of second ligand; Preparation of gallium benzoate complex.

In the past decade, tremendous progress has been made in organic field-effect transistors (OFETs). Their real applications require further development of device performance. OFETs consist of organic semiconductors, dielectric layers, and electrodes. Organic semiconductors play a key role in determining the device characteristics. The properties of the organic semiconductors, such as molecular structure and packing, as well as molecular energy levels, can be properly controlled by molecular design. Therefore, we designed and synthesized a series of organic molecules. The synthesized organic semiconductors exhibit excellent field-effect properties due to strong intermolecular interactions and proper molecular energy levels. Meanwhile, the influence of the device fabrication process, organic semiconductor/dielectric layer interface, and organic layer/electrode contact on the device performance was investigated. A deep understanding of these factors is helpful to improve field-effect properties. Furthermore, single-crystal field-effect transistors are highlighted because the single-crystal-based FETs can provide an accurate conducting mechanism of organic semiconductors and higher device performance as compared with thin film FETs. [ABSTRACT FROM AUTHOR]

We report a regioregular bis-pyridal[2,1,3]- thiadiazole (BPT) acceptor strategy to construct the first ambipolar pyridal[2,1,3]thiadiazole-based semiconducting polymer (PBPTV). The use of BPT unit enables PBPTV to achieve high electron affinity, low LUMO level, and extended π-conjugation. All these factors provide PBPTV with encouraging hole and electron mobilities up to 6.87 and 8.49 cm² V-1 s-1, respectively. Our work demonstrates that the BPT unit is a promising building block for designing high-performance electron-transporting semiconductors in organic electronics. [ABSTRACT FROM AUTHOR]

The article describes organic field-effect transistors (OFET) with 1-imino nitroxide pyrene as the semiconductor layer. The device can be operated within low voltage and demonstrates excellent p-type FET characteristics. The UV-vis spectrum of 1-imino nitroxide pyrene in dichloromethane possess three main absorption peaks centered at 244, 278 and 345 nm. The device was fabricated on a silica/Si substrate with top-contact configuration.

The article focuses on the comprehensive review regarding the performance of л-conjugated systems in organic field-effect transistors (OFETs) based on semiconducting л-conjugated materials. It says that optimization of molecular design and device physics have influenced the high performance of OFETs. It mentions others factors that are important to the optimization of OFETs including device configuration, thickness of semiconducting layer and channel length and width.

Organic semiconductor nanoparticles are expected to be used in organic optical and electronic devices due to their unique optical and electrical properties. However, no method has been reported for the preparation of high-quality organic nanoparticle films without remaining additives and being capable of dealing with binary nanoparticle blends. We developed a simple approach to fabricate high-quality organic semiconductor nanoparticle films from their aqueous solutions by solvent-evaporation-induced self-assembly. Only volatile solvents are employed in the nanoparticle solutions, so the self-assembled nanoparticle films are free of additives. Moreover, this method is also suitable for fabricating thin films containing binary nanoparticles. Therefore, it paves the way for potential applications of organic semiconductor nanoparticles in nanoscale optical and electronic devices. [ABSTRACT FROM AUTHOR]

Two trifluoromethyltriphenodioxazines were efficiently synthesized as active materials for n-type organic field-effect transistors, and their optical and electrochemical properties were characterized. Air-stable and high-performance thin film transistors based on the two compounds were fabricated. [ABSTRACT FROM AUTHOR]

In this paper, (1) a simple and controllable method to synthesize single crystalline nanoribbons of CuTCNQ in a large area was demonstrated by using a physical and chemical vapor combined deposition technique. (2) Nanoribbons synthesized by this method were identified to belong to phase I. (3) Devices and device arrays of nanoribbons were in situ fabricated by this method using gap electrodes and gap electrode arrays. (4) Current-voltage characteristics of crystalline devices and device arrays of nanoribbons exhibited semiconductor properties, and this conclusion was further confirmed by the results of devices based on an individual nanoribbon or microribbon of CuTCNQ (phase I). The controllable synthesis of nanoribbons for the in situ fabrication of crystalline nanodevices and device arrays will be attractive for nanoelectronics. Moreover, semiconductor current-voltage characteristics of the nanoribbons will be beneficial to the understanding of CuTCNQ. [ABSTRACT FROM AUTHOR]

The article focuses on the development of core-expanded naphthalene diimides mixed with 2-(1,3-dithiol-2-Ylidene) malonitrile groups. It notes that these organic semiconductors are used as active layers for ambient-stable, high-performance, and solution-processed n-channel organic thin film transistors. They can be considered as great potential in organic electronics due to their excellent air and operating stability.

The article presents information on a study of a new class of a high-performance organic field-effect transistor (OFET) semiconductor based on perylo [1, 12-b, c, d] thiophene (PET). It has been found that the integration of a S atom into the polycyclic aromatic hydrocarbon (PAH) skeleton induces an extraordinary solid-state packing arrangement with the likelihood of double-channel superstructure. As a control result, the thin-film field-effect behavior of PET has been investigated first.

The article discusses several characteristics of organic field-effect transistors (OFETs), transistors fabricated from organic conjugated heterocyclic compounds. OFETs have drawn growing interest because of their easier fabricating and lower cost than with traditional silicon-based transistors. They can be ideally used in large area and light plastic circuits on adaptable substrates in electronic devices.