Organic semiconductors for organic field-effect transistors

Yamashita, Yoshiro

doi:10.1088/1468-6996/10/2/024313

Cited by 266 publications

(155 citation statements)

References 65 publications

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“…In other words, molecules involving π-conjugation have high HOMO levels and exhibit electron-donating properties. Hence, these molecules are good candidates for p-type semiconductors [68].…”

Section: Molecule As Semiconductormentioning

confidence: 99%

Metal−Molecule Schottky Junction Effects in Surface Enhanced Raman Scattering

2010

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We propose a complementary interpretation of the mechanism responsible for the strong enhancement observed in Surface Enhanced Raman Scattering (SERS). The effect of a strong static local electric field due to Schottky barrier at the metal-molecule junction on SERS is systematically investigated. The study provides a viable explanation to the low repeatability of SERS experiments as well as the Raman peak shifts as observed in SERS and raw Raman spectra. It was found that strong electrostatic build-in field at the metal-molecule junction along specific orientations can result in 2-4 more orders of enhancement in SERS.

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Section: Molecule As Semiconductormentioning

confidence: 99%

Metal−Molecule Schottky Junction Effects in Surface Enhanced Raman Scattering

2010

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“…Bulk KxPentacene (x = 1, 2 and 3.6) has previously been reported without structural characterisation, [17][18][19] and metallic conductivity has been reported in potassium-doped pentacene thin films. [20][21][22][23][24] As pentacene is more readily available than picene, we chose initially to address the synthesis of potassium-intercalated pentacene samples suitable for structural analysis, before applying these protocols to the picene system. …”

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confidence: 99%

Redox-controlled potassium intercalation into two polyaromatic hydrocarbon solids

et al. 2017

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Alkali metal intercalation into polyaromatic hydrocarbons (PAHs) has been studied intensely following reports of superconductivity in a number of potassium-and rubidium-intercalated materials. There are however no reported crystal structures to inform understanding of the chemistry and physics because of the complex reactivity of PAHs with strong reducing agents at high temperature. Here we present the synthesis of crystalline K2Pentacene and K2Picene by a solid-solid insertion protocol that uses potassium hydride as a redox-controlled reducing agent to access the PAH dianions, enabling determination of their crystal structures. In both cases, the inserted cations expand the parent herringbone packings by reorienting the molecular anions to create multiple potassium sites within initially dense molecular layers, and thus interact with the PAH anion π-systems. The synthetic and crystal chemistry of alkali metal intercalation into PAHs differs from that into fullerenes and graphite, where the cation sites are pre-defined by the host structure.Reaction of alkali and alkaline earth metals with carbon-based molecular solids has been extensively studied in the search for novel magnetic and electronic properties, with a particular focus on superconductivity. [1][2][3][4][5][6] For example, alkali metal intercalation into solid C60 produces A3C60 superconductors, with Tc as high as 38 K for Cs3C60 at 7 kbar. 6 In these materials, cations occupy the interstitial voids that already exist in the host e.g., in the fcc lattice of C60 (Figure 1). 7 Reaction of potassium with picene (C22H14), a phenacene composed of five fused benzene rings, has been reported to afford superconductivity at 18 K. 8 Superconductivity in other alkali-metal polyaromatic hydrocarbons (PAHs) was subsequently reported in phenanthrene-, dibenzopentacene-and coronene-based materials, with the highest reported Tc of 33 K claimed 2 in potassium-doped 1,2:8,9-dibenzopentacene. [9][10][11] Despite the significant interest in these materials, to date no crystal structure has been determined for any of the alkali-metal PAH systems. This structural information is a prerequisite for materials design and for understanding of both physical properties and reaction chemistry.Picene, like many other PAHs (including molecules such as phenanthrene 12 which is reported to afford superconductivity on cation insertion), crystallises in the herringbone structure, 13 with layers consisting of two parallel one-dimensional chains of molecules with opposing inclinations defined by an intermolecular angle, ω, of 57.89(7)° (Supplementary Figure 1). 14 The largest voids in the structure are located between the picene layers, adjacent to the saturated C-H bonds and far from the electron density of the PAH π-systems ( Figure 1a). This contrasts with C60, where the octahedral and tetrahedral voids in the fcc lattice are adjacent to the conjugated π-electron system (Figure 1b Pentacene is the linear isomer of picene, and also adopts the herringbone structure, 16 with ω = 52...

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“…This activity may be attributed to the conjugate structure of the benzene ring and the amide bond, whether in space or electron density, which facilitates formation of intermolecular interactions with the receptor binding sites. Thus, the affinity of the compounds and receptor is enhanced [27] . This structure-activity relationship is also nmol/L, respectively.…”

Section: Discussionmentioning

confidence: 99%

A cell-based, high-throughput homogeneous time-resolved fluorescence assay for the screening of potential κ-opioid receptor agonists

et al. 2014

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Aim: The aim of this study was to identify κ-opioid receptor (KOR) agonists from a library of 80 000 small-molecule compounds and provide the experimental basis for the development of new analgesic candidates. Methods: The cell-based, high-throughput screen for human KOR agonists was based on the LANCE TM cAMP assay. Preliminary structure-activity relationship (SAR) analysis was applied according to the compounds' structures. An acetic acid twisting experiment was used to verify the pharmacodynamics. Results: In total, 31 compounds were identified as KOR agonists after preliminary and secondary screening. Of these compounds, five demonstrated significant KOR-stimulating activity that was comparable to U-50,488, a selective KOR agonist. The EC 50 values for I-7, I-8, I-10, II-5, and II-8 were 13.34±1.65, 14.01±1.84, 9.57±0.19, 14.94±0.64, and 8.74±0.72 nmol/L, respectively. Based on SAR studies, the stimulating activity of compounds with 5-phenyl-7-(trifluoromethyl)-4,5,6,7-tetrahydropyrazolo [1, 5-a] pyrimidine (group I) and 3,4-dimethoxy-N-(2-oxoethyl)-N-p-tolylbenzenesulfonamide (group II) parent structures were higher than the compound with a 5-hydroxy-2-methylbenzofuran-3-carboxylic acid (group III) parent structure. Pharmacodynamic experiments indicated that 20-40 μg/kg ip of compounds I-10 and II-8 significantly decreased the number of writhes induced by acetic acid; this finding is consistent with the SAR studies. Furthermore, the analgesic effects of compounds I-10 and II-8 were significantly antagonized in the presence of the selective KOR antagonist nor-BNI. Conclusion: These findings collectively indicate that compounds I-10 and II-8 exhibit significant analgesic activities, providing evidence, at least in part, for their clinical application as new analgesic drugs.

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Organic semiconductors for organic field-effect transistors

Cited by 266 publications

References 65 publications

Metal−Molecule Schottky Junction Effects in Surface Enhanced Raman Scattering

Metal−Molecule Schottky Junction Effects in Surface Enhanced Raman Scattering

Redox-controlled potassium intercalation into two polyaromatic hydrocarbon solids

A cell-based, high-throughput homogeneous time-resolved fluorescence assay for the screening of potential κ-opioid receptor agonists

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