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Heterocycle‐linked phthalocyanine‐based COFs with close‐packed π–π conjugated structures are a kind of material with intrinsic electrical conductivity, and they are considered to be candidates for photoelectrical devices. Previous studies have revealed their applications for energy storage, gas sensors, and field‐effect transistors. However, their potential application in photodetector is still not fully studied. The main difficulty is preparing high‐quality films. In our study, we found that our newly designed benzimidazole‐linked Cu (II)‐phthalocyanine‐based COFs (BICuPc‐COFs) film can hardly formed with a regular aerobic oxidation method. Therefore, we developed a transfer dehydrogenation method with N‐benzylideneaniline (BA) as a mild reagent. With this in hand, we successfully prepared a family of high crystalline BICuPc‐COFs powders and films. Furthermore, both of these new BICuPc‐COFs films showed high electrical conductivity (0.022–0.218 S/m), higher than most of the reported COFs materials. Due to the broad absorption and high conductivity of BICuPc‐COFs, synaptic devices with small source‐drain voltage (VDS=1 V) were fabricated with response light from visible to near‐infrared. Based on these findings, we expect this study will provide a new perspective for the application of conducting heterocycle‐linked COFs in synaptic devices. [ABSTRACT FROM AUTHOR]

Ambipolar polymer semiconductors are potentially serviceable for logic circuits, light-emitting field-effect transistors (LFETs) and polymer solar cells (PSCs). Although several high-performance ambipolar polymers have been developed, their optoelectronic devices are generally processed from toxic chlorinated solvents. To achieve the commercial applications of organic FETs (OFETs), the polymers should be processed from nonchlorinated solvents, instead of chlorinated solvents. However, most conjugated polymers show poor solubility in nonchlorinated solvents. It is of great importance to develop ambipolar polymers that can be processed from nonchlorinated solvents. Here, we develop a nonchlorinated solvent processed polymer named poly[7-fluoro-N, N′-di(4-decyltetradecyl)-7′-azaisoindigo-6′,6″-(thieno[3,2-b]thiophene-2,5-diyl)-7‴-fluoro-N″, N‴-di(4-decyltetradecyl)-7″-azaisoindigo-6,6‴-([2,2″-bithiophene]-5,5″-diyl)] (PITTI-BT) by designing a monomer with a large molar mass. The polymer displays good solubility in p-xylene (PX). Well-aligned films of PITTI-BT are achieved by an off-center spin-coating (SC) method. Based on the high-quality films, the OFETs fabricated from PX solution achieve record ambipolar performance with hole and electron mobilities of 3.06 and 2.81 cm2 V−1 s−1, respectively. The combination of nonchlorinated solvents and good alignment process offers an effective and eco-friendly approach to obtain high-performance ambipolar transistors. [ABSTRACT FROM AUTHOR]

Organic field-effect transistors (OFETs) have received considerable attention across the world due to their potential applications in integrated circuits for large-area, flexible and low-cost electronics, and a series of breakthroughs in their research have been made in the past decade. Although numerous novel organic semiconductive materials with outstanding properties have been synthesized, the fabrication of OFETs and the investigation of amorphous polymer insulators (APIs) are attracting more and more research interest due to their significance in semiconductor growth, charge transport and device stability. In this review, an introduction to APIs and OFETs is given, and the following aspects are then successively discussed: commonly used APIs in OFETs, applications of API in high-performance OFETs, low-energy-consumption OFETs, functional OFETs, and self-healing OFETs. In the last section, a projection of some future trends for APIs in OFETs is presented. [ABSTRACT FROM AUTHOR]

Polymer field-effect transistors (PFETs) are promising candidates for future electronics due to easy and inexpensive fabrication. Poly{[ N , N ′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene) [P(NDI2OD-T2)] based PFET devices with poly (methyl 2-methylpropenoate) (PMMA) as dielectric were fabricated successfully and it was found that the charge transporting behaviors were greatly impacted by the molecular weight of PMMA. Both hole and electron mobilities were improved simultaneously with increasing molecular weight of PMMA. In addition, similar result was also obtained in the PFETs based on a semiconductor, poly{[ N , N ′-bis(2-octyldodecyl)-1,4,5,8-naphthalenediimide-2,6-diyl-alt-5,5′-di(thiophen-2-yl)-2,2′-(E)-2-(2-(thiophen-2-yl)vinyl)thiophene]}. Furthermore, the corresponding complementary-like inverters with PMMA displayed a gain value of 100. We studied the interface between the semiconducting and dielectric layers and found that the low trap density with higher-molecular-weight PMMA attributes to high mobilities of electrons and holes. This work provides a new way to fabricate high-performance PFETs and to improve performance of the complementary circuits through studying the effects of polymeric gate dielectrics, compared to the conventional view of semiconducting materials. [ABSTRACT FROM AUTHOR]

ABSTRACT Two furan-flanked polymers poly{3,6-difuran-2-yl-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thienylenevinylene} (PDVFs), with a highly π-extended diketopyrrolopyrrole backbone, are developed for solution-processed high-performance polymer field-effect transistors (FETs). Atomic force microscopy and grazing incidence X-ray scattering analyses indicate that PDVF-8 and PDVF-10 films exhibit a similar nodular morphology with the ultrasmall lamellar distances of 16.84 and 18.98 Å, respectively. When compared with the reported polymers with the same alkyl substitutes, this is the smallest d-spacing value observed to date. This closed lamellar crystallinity facilitates charge carrier transport. Therefore, polymer thin-film transistors fabricated from as-spun PDVF-8 films exhibit a high hole mobility exceeding 1.0 cm2 V−1 s−1 with a current on/off ratio above 106. After annealing treatment at 100 °C in air, the highest hole mobility of PDVF-8-based FETs was significantly improved to 1.90 cm2 V−1 s−1, which is among the highest values of the reported FET devices fabricated from polymer thin films based on this mild annealing temperature. In contrast, long alkyl-substituted PDVF-10 exhibited a relatively low hole mobility of 1.65 cm2 V−1 s−1 mainly resulting from low molecular weight. This work demonstrated that PDVFs would be promising semiconductors for developing cost-effective and large-scale production of flexible organic electronics. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1970-1977 [ABSTRACT FROM AUTHOR]

'Regioselectivity deposition' method is developed to pattern silver electrodes facilely and efficiently by solution-process with high resolution (down to 2 μm) on different substrates in A4 paper size. With the help of this method, large-area, flexible, high-performance polymer field-effect transistors based on the silver electrodes and polyimide insulator are fabricated with bottom-contact configuration by all-solution processes. The polymer devices exhibit high performance with average field-effect mobility over 1.0 cm2 V−1 s−1 (the highest mobility up to 1.5 cm2 V−1 s−1) and excellent environmental stability and flexibility, indicating the cost effectiveness of this method for practical applications in organic electronics. [ABSTRACT FROM AUTHOR]

We report the synthesis of two noveldonor–acceptor copolymerspoly{[N, N′-bis(alkyl)-1,4,5,8-naphthalenediimide-2,6-diyl-alt-5,5′-di(thiophen-2-yl)-2,2′-(E)-2-(2-(thiophen-2-yl)vinyl)thiophene]} (PNVTs) based onnaphthalenediimide (NDI) acceptor and (E)-2-(2-(thiophen-2-yl)vinyl)thiophenedonor. The incorporations of vinyl linkages into polymer backbonesmaintain the energy levels of the lowest unoccupied molecular orbitsat −3.90 eV, therefore facilitating the electron injection.Moreover, the energy levels of the highest occupied molecular orbitsincrease from −5.82 to −5.61 eV, successfully decreasingthe hole injection barrier. Atomic force microscopy measurements indicatethat PNVTs thin films exhibit larger polycrystalline grains comparedwith that of poly{[N, N′-bis(2-octyldodecyl)-1,4,5,8-naphthalenediimide-2,6-diyl]-alt- 5,5′-(2,2′-bithiophene)}[P(NDI2OD-T2)], consistent with the stronger π–πstacking measured by grazing incidenceX-ray scatting. To optimize devices performance, field-effect transistors(FETs) with three devices configurations have been investigated. Theresults indicate that the electron mobility of the vinyl-containingPNVTs exhibit about 3–5 times higher than that of P(NDI2OD-T2).Additionally, the vinyl-linkages in PNVTs remarkably enhance ambipolartransport of their top-gate FETs, obtaining high hole and electronmobilities of 0.30 and 1.57 cm2V–1s–1, respectively, which are among the highest valuesreported to date for the NDI-based polymers. Most importantly, ambipolarinverters have been realized in ambient, exhibiting a high gain of155. These results provide important progresses in solution-processedambipolar polymeric FETs and complementary-like inverters. [ABSTRACT FROM AUTHOR]

In this study, we successfully designed and synthesized a novel phenanthro[1,10,9,8- c,d,e,f,g]carbazole ( PCZ)-based copolymer poly[ N-(2-octyldodecyl)-4,8-phenanthro[1,10,9,8- c,d,e,f,g]carbazole- alt-2,5-dihexadecyl-3,6-di(thiophen-2-yl)pyrrolo[3,4- c]pyrrole-1,4(2 H,5 H)-dione] ( PPDPP) with an extended π-conjugation along the vertical orientation of polymer main chain. This polymer exhibited excellent solubility in common solvent and high thermal stability, owning good properties for solution-processed field-effect transistors (FETs). Besides, absorption spectra demonstrated that annealing PPDPP thin films led to obviously red-shifted maxima, indicating the formations of aggregation or orderly π-π stacking in their solid-state films. X-ray diffraction measurements indicated the crystallinity of PPDPP thin films was enhanced after high temperature annealing, which was favorable for charge transport. The solution-processed PPDPP-based FET devices were fabricated with a bottom-gate/bottom-contact geometry. A high hole mobility of up to 0.30 cm2/Vs and a current on/off ratio above 105 had been demonstrated. These results indicated that the copolymers constructed by this kind of ladder-type cores could be promising organic semiconductors for high-performance FET applications. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 [ABSTRACT FROM AUTHOR]

Abstract: Dithienothiophene-phenylene cooligomers with n-hexyloxy or n-dodecyloxy substituents have been synthesized and compared to the previously reported unsubstituted parent compound. The effect of substituents on the thermal, electronic, optical, thin film structure and field-effect transistor (OFET) properties was investigated. Structural phase transitions from highly-ordered nanocrystalline to liquid crystalline were observed at 241 and 213 °C for n-hexyloxy- and n-dodecyloxy-substituted compounds respectively, different from the parent compound. For the alkoxy-substituted compounds, the absorption spectra in thin film blue shift 50 nm, while the fluorescence spectra in thin film red shift 88–100 nm compared to those in solution. The OFET devices based on the alkoxy-substituted compounds exhibit mobilities as high as ca 0.02 cm2V−1s−1 and their performance is sensitive to the alkoxy substituents and substrate temperatures. [Copyright &y& Elsevier]

A diketopyrrolopyrrole–thiazolothiazole copolymer with a short π–π stacking distance (3.52 Å), due to the introduction of heteroaromatic rings, exhibits a high charge mobility above 3.40 cm2 V−1 s−1 at a relatively gentle annealing temperature. [ABSTRACT FROM AUTHOR]

Abstract: 2,6-Dialkylphenyldithieno[3,2-b:2′,3′-d]thiophene derivatives (DPCn–DTT) were synthesized and characterized. Effect of alkyl groups on optical characteristics, electrochemical properties, film-forming ability, and field-effect performance was studied. The four compounds DPCn–DTT show almost the same energy levels of the highest occupied molecular orbits and optical energy gaps, but they exhibit different charge carrier transport characteristics. The thin film transistors based on DPC1–DTT with the shortest alkyl groups (methyl groups) show the highest mobility of 0.54 cm2 V−1 s−1. Substrate temperature and surface modification of the SiO2 insulators have a remarkable effect on field-effect performance. High-quality microribbons of DPC8–DTT with octyl groups were prepared by a solution-phase self-assembly process. Single crystal field-effect transistors based on an individual DPC8–DTT microribbon exhibit a high mobility of 1.1 cm2 V−1 s−1 with a current on/off ratio of 6.5 × 104. [Copyright &y& Elsevier]