排序方式: 共有21条查询结果,搜索用时 31 毫秒
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Guo X Ortiz RP Zheng Y Hu Y Noh YY Baeg KJ Facchetti A Marks TJ 《Journal of the American Chemical Society》2011,133(5):1405-1418
Developing new high-mobility polymeric semiconductors with good processability and excellent device environmental stability is essential for organic electronics. We report the synthesis, characterization, manipulation of charge carrier polarity, and device air stability of a new series of bithiophene-imide (BTI)-based polymers for organic field-effect transistors (OFETs). By increasing the conjugation length of the donor comonomer unit from monothiophene (P1) to bithiophene (P2) to tetrathiophene (P3), the electron transport capacity decreases while the hole transport capacity increases. Compared to the BTI homopolymer P(BTimR) having an electron mobility of 10(-2) cm(2) V(-1) s(-1), copolymer P1 is ambipolar with balanced hole and electron mobilities of ~10(-4) cm(2) V(-1) s(-1), while P2 and P3 exhibit hole mobilities of ~10(-3) and ~10(-2) cm(2) V(-1) s(-1), respectively. The influence of P(BTimR) homopolymer M(n) on film morphology and device performance was also investigated. The high M(n) batch P(BTimR)-H affords more crystalline film microstructures; hence, 3× increased electron mobility (0.038 cm(2) V(-1) s(-1)) over the low M(n) one P(BTimR)-L (0.011 cm(2) V(-1) s(-1)). In a top-gate/bottom-contact OFET architecture, P(BTimR)-H achieves a high electron mobility of 0.14 cm(2) V(-1) s(-1), only slightly lower than that of state-of-the-art n-type polymer semiconductors. However, the high-lying P(BTimR)-H LUMO results in minimal electron transport on exposure to ambient. Copolymer P3 exhibits a hole mobility approaching 0.1 cm(2) V(-1) s(-1) in top-gate OFETs, comparable to or slightly lower than current state-of-the-art p-type polymer semiconductors (0.1-0.6 cm(2) V(-1) s(-1)). Although BTI building block incorporation does not enable air-stable n-type OFET performance for P(BTimR) or P1, it significantly increases the OFET air stability for p-type P2 and P3. Bottom-gate/top-contact and top-gate/bottom-contact P2 and P3 OFETs exhibit excellent stability in the ambient. Thus, P2 and P3 OFET hole mobilities are almost unchanged after 200 days under ambient, which is attributed to their low-lying HOMOs (>0.2 eV lower than that of P3HT), induced by the strong BTI electron-withdrawing capacity. Complementary inverters were fabricated by inkjet patterning of P(BTimR)-H (n-type) and P3b (p-type). 相似文献
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Park CB Lee SH Subramanian E Kale BB Lee SM Baeg JO 《Chemical communications (Cambridge, England)》2008,(42):5423-5425
A new potentially promising visible-light driven photobioreactor synthesizes fine chemical via photobiocatalysis by generating NADH in a non-enzymatic light-driven process and coupling it to the enzymatic dark reaction catalysis. 相似文献
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In this study, a visible-light-driven photocatalytic system for the generation of dihydronicotinamide adenine dinucleotide (NADH) from aqueous protons was examined using cobaloxime as a catalyst, eosin as a photosensitizer, and triethanolamine as a sacrificial electron donor. Irradiation of a reaction solution containing cobaloxime, eosin, and triethanolamine (TEOA) converted NAD(+) to NADH with a yield of 36% in a phosphate buffer. The reaction rates for the production of NADH were dependent on the concentrations of the catalyst, NAD(+), and TEOA. Introduction of an electron-donating or -withdrawing substituent in the para position of the pyridine changed the rate constant and affected the conversion efficiency. The rates obtained by the different substituents were linearly correlated with the Hammett coefficients of the introduced substituents. Last, reduction of CO(2) was carried out in the presence of formate dehydrogenase using NADH photochemically generated using the cobaloxime/eosin/TEOA system. 相似文献
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Huang H Chen Z Ponce Ortiz R Newman C Usta H Lou S Youn J Noh YY Baeg KJ Chen LX Facchetti A Marks T 《Journal of the American Chemical Society》2012,134(26):10966-10973
Understanding the relationship between molecular/macromolecular architecture and organic thin film transistor (TFT) performance is essential for realizing next-generation high-performance organic electronics. In this regard, planar π-conjugated, electron-neutral (i.e., neither highly electron-rich nor highly electron-deficient) building blocks represent a major goal for polymeric semiconductors, however their realization presents synthetic challenges. Here we report that an easily accessible (minimal synthetic steps), electron-neutral thienyl-vinylene (TVT)-based building block having weak intramolecular S···O "conformational locks" affords a new class of stable, structurally planar, solution-processable, high-mobility, molecular, and macromolecular semiconductors. The attraction of merging the weak TVT electron richness with supramolecular planarization is evident in the DFT-computed electronic structures, favorable MO energetics, X-ray diffraction-derived molecular structures, experimental lattice coehesion metrics, and excellent TFT performance. TVT-based polymer TFTs exhibit stable carrier mobilities in air as high as 0.5 and 0.05 cm(2)/V·s (n- and p-type, respectively). All-TVT polymer-based complementary inverter circuitry exhibiting high voltage gains (~50) and ring oscillator circuitry with high f(osc)(~1.25 kHz) is readily fabricated from these materials by simple inkjet printing. 相似文献
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Soumya Kanti Biswas Jin-Ook Baeg Sang-Jin Moon Ki-jeong Kong Won-Wook So 《Journal of nanoparticle research》2012,14(1):667-12
Different morphologies of WO3 nanocrystals such as nanorods and nanoplates have been obtained under hydrothermal conditions using ammonium metatungstate
as the precursor in presence of different organic acids such as citric, oxalic, and tartaric acid in the reaction medium.
Detailed characterization of the crystal structure, particle morphology, and optical band gap of the synthesized powders have
been done by X-ray diffraction, transmission electron microscopy, scanning electron microscopy and solid-state UV–visible
spectroscopy study. The as-synthesized materials are WO3 hydrates with orthorhombic phase which transform to the hexagonal WO3 through dehydration upon heating at 350 °C. The resultant products are crystalline with nanoscale dimensions. Finally, the
photoactivity of the synthesized materials annealed at 500 °C has been compared employing in photoelectrochemical water oxidation
under the illumination of AM 1.5G simulated solar light (100 mWcm−2). The photocurrent measurements upon irradiation of light exhibit obvious photocatalytic activity with a photocurrent of
about 0.77, 0.61, and 0.65 mAcm−2 for the WO3 film derived with the oxalic acid, tartaric, and citric acid assisting agents, respectively, at 1.8 V versus Ag/AgCl electrode. 相似文献
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M H MOGHTADER DINDARLU M KAVOSH TEHRANI H SAGHAFIFAR A MALEKI GH SOLOOKINEJAD M JABBARI 《Pramana》2017,88(2):36
In this paper, an analytical model for temperature distribution of the side-pumped laser rod is extracted. This model can be used for side-pumped laser rods whose absorbed pump profile is a Gaussian profile. Then, it is validated by numerical results which exhibit a good agreement with the analytical results. Afterwards, by considering a general expression for super-Gaussian and top-hat profiles, and solving the heat equation, the influence of profile width and super-Gaussian exponent of the profile on temperature distribution are investigated. Consequently, the profile width turns out to have a greater influence on the temperature compared to the type of the profile. 相似文献
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Methyl-methine linkages of Novolac, a commercially available t-butylphenol acetylene condensed (TBPA) resin, have been identified by recognition of pyrolysis pathways using pyrolysis-gas chromatography/mass spectrometry (Py-GC/mS) in vulcanized rubber. The diagnostic mass spectrum of t-butylphenol with methyl-methine linkages between phenolic rings was observed at m/z 192, corresponding to 4-t-butyl-2-ethyl-6-methylphenol. Other molecular ions were observed at m/z 178, 164, and 150 in the characteristic pyrolyzates. The ion at m/z 192 in the TBPA resin was observed to be characteristic for methyl-methine linkages between the phenolic groups, and the analytical pyrolysis-GC/mS method was thus able to identify the resin at low levels in vulcanized rubber. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
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