A5084224981- Organic Electronics and Photovoltaics
- Liquid Crystal Research Advancements
- Conducting polymers and applications
- Thin-Film Transistor Technologies
- Photochemistry and Electron Transfer Studies
- Photonic and Optical Devices
- Synthesis and properties of polymers
- Photochromic and Fluorescence Chemistry
- Molecular Junctions and Nanostructures
- Nanowire Synthesis and Applications
- Organic Light-Emitting Diodes Research
- Semiconductor Lasers and Optical Devices
- Perovskite Materials and Applications
- Nonlinear Optical Materials Research
- Advancements in Semiconductor Devices and Circuit Design
- Surfactants and Colloidal Systems
- Analytical Chemistry and Sensors
- Porphyrin and Phthalocyanine Chemistry
- Organic and Molecular Conductors Research
- Nonlinear Dynamics and Pattern Formation
- Synthesis and Properties of Aromatic Compounds
- Semiconductor materials and devices
- Nanofabrication and Lithography Techniques
- Advanced Sensor and Energy Harvesting Materials
- Molecular spectroscopy and chirality
Institute for Future Engineering
2025
Tokyo Institute of Technology
2015-2024
Japan Science and Technology Agency
2008-2013
Dai Nippon Printing (Japan)
2007
Abstract Crystalline thin films of organic semiconductors are a good candidate for field effect transistor (FET) materials in printed electronics. However, there currently two main problems, which associated with inhomogeneity and poor thermal durability these films. Here we report that liquid crystalline exhibiting highly ordered crystal phase smectic E (SmE) can solve both problems. We design SmE material, 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-10), FETs...
Polycrystalline thin films fabricated from a liquid crystalline phase are quite uniform both on the millimeter and nanometer scale. The polycrystalline established by two model materials, dialkylated terthiophene benzothienobenzothiophene derivatives, show high FET mobility, 0.1 3.0 cm2 V−1 s−1, respectively. Such not obtained post thermal annealing.
Atomically flat two-dimensional networks of boron are attracting attention as post-graphene materials. An introduction cations between the atomic layers can exhibit unique electronic functions that not achieved by neutral graphene or its derivatives. In present study, we propose a synthesis strategy for ion-laminated layered materials in solution phase, which enables preparation analogs changing alkali-metal species. The large extends thermal range liquid-crystal phases because weakened...
1,4,8,11,15,18,22,25-Octaoctylphthalocyanine shows the highest time-of-flight (“long-range”) hole mobility so far reported for columnar phase of a discotic liquid crystal. Unlike most other high long-range discotics, there is no clear evidence from x-ray diffraction order.
We have investigated the negative charge carrier transport in discotic columnar phases of triphenylene derivatives, 2,3,6,7,10,11-hexapentyloxytriphenylene (H5T) and its related derivatives such as H4T H6T, by time-of-flight experiments. observed a fast transit for carriers hexagonal phase $({D}_{h})$ H5T, which corresponded to high mobility...
We have investigated charge carrier transport in the various phases of metal-free phthalocyanine derivative, 1,4,8,11,15,18,22,25-octaoctylphthalocyanine (8H 2 Pc), by time-of-flight method. The discotic columnar phase 8H Pc easily self-organizes columns perpendicular to substrate when cooled from isotropic phase. found that well-defined transits were observed, not only for positive carriers, but also negative carriers. For rectangular at 85°C hole and electron mobilities very high 0.2 0.3...
Low-voltage operable organic field-effect transistors (OFETs) of 2-decyl-7-phenyl-[1] benzothieno[3,2-b][1] benzothiophene (Ph-BTBT-10) with low- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$k$ </tex-math></inline-formula> polystyrene/SiO <sub xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> hybrid gate dielectric are fabricated using highly ordered smectic E (SmE) liquid crystalline phase. SmE phase...
Negative charge carrier transport has been investigated in the columnar mesophases of 2,3,6,7,10,11-hexahexylthiotriphenylene (HHTT), (the best-known conducting discotic liquid crystal because its high bulk hole mobility) using time-of-flight method. It was shown that fast electron takes place highly ordered helical phase. The mobility 0.08cm2V−1s−1 at 45°C, which same as reported previously. Electron also observed lower-order hexagonal phase, but an additional slow transit appeared...
We have investigated the availability of liquid crystalline thin films as a precursor quality polycrystalline for organic field effect transistors (OFETs) by solution process. The experiments spin-coating at various temperatures proved that morphology resulting room temperature strongly depend on what immediately after and solvent evaporation those were, i.e., crystal, or isotropic liquid. spin-coated crystal phases were much roughened owing to many small flakes droplets. On other hand, very...
We have characterized the crystallographic features and charge carrier transport properties of polycrystalline films both triphenylene terthiophene derivatives, which are representative materials discotic (disc-like) calamitic (rod-like) liquid crystals, respectively. Because enhanced anisotropy with hydrocarbon chains in their molecular structure pre-ordered alignment mesophase, exhibit a particular texture indicating that liquid-crystalline phase is well preserved, suppresses formation...
The fabrication of organic semiconductor thin films by printing technologies is expected to enable the low-cost production devices such as flexible display drivers, RF-ID tags, and various chemical/biological sensors. However, large-scale high-speed uniform with adequate electrical properties for these remains a big challenge. Herein, we demonstrate an ultrafast scalable polycrystalline 100% surface coverage using liquid crystalline semiconductors...
Abstract We have investigated the fabrication of crystalline thin films a liquid organic semiconductor (2-decyl-7-phenyl[1]benzothieno[3,2-b][1]benzothiophene: Ph-BTBT-10) by high-speed blade-coating at 140 mm s −1 . Uniform Ph-BTBT-10 were fabricated temperatures over 50 °C, which is temperature crystal phase, without inhomogeneous recrystallization, despite blade-coating. Transistors using these showed high average carrier mobility 4.8 cm 2 Vs for 26 devices, with coefficient variation...
We investigated charge-carrier transport in the nematic phase of small molecules such as 2-phenylbenzothiazoles by time-of-flight experiments, which conduction mechanism has been considered to be ionic. As a result, we established hole and electron transports highly purified samples: found that there were two transits, namely, fast slow less pure samples; transit was attributed ionic originating from trace amounts impurities electronic whose attribution elucidated mobility changes diluted...
We have investigated negative charge carrier transport in the smectic mesophases of 2-phenylnaphthalene derivative, 6-(4'-octylphenyl)-2-dodecyloxynaphthalene (8-PNP-O12), using time-of-flight (TOF) method. revealed that its had two different mechanisms, i.e., electronic and ionic conductions: we observed transits carriers both A (SmA) B (SmB) phases demonstrated their origins by dilution experiments with a hydrocarbon (n-dodecane); fast transit was attributed to electrons slow one ions....
Hole transport has been investigated by the time-of-flight method for hexagonal columnar phase of a discogen containing strongly dipolar nitro substituent; 1-nitro-2,3,6,7,10,11-hexakis(hexyloxy)triphenylene (HAT6-NO2). Unlike corresponding unsubstituted system, 2,3,6,7,10,11-hexakis(hexyloxy)triphenylene (HAT6), and unlike most other liquid crystals, mobility in HAT-NO2 depends on both electric field temperature. As amorphous solids there is disorder dominated hopping can be modeled using...
Two benzoporphyrin derivatives substituted with long side chains at the bay positions have been synthesized through a facile route. They were confirmed to show two separate columnar phases upon cooling, i.e., hexagonal phase and rectangular phase. In particular, temperature dependence of electronic spectra revealed that Q-band split into peaks, indicating existence typical herringbone-type dimers. Moreover, their photoconductive properties studied by steady-state transient photocurrent...
We investigated the negative carrier transport in discotic columnar phases of three triphenylene derivatives by time-of-flight experiments. found that transient photocurrents had two transits carriers, which appeared different time ranges. The mobilities obtained from fast transit were 2×10-2, 2×10-3, and 4×10-4 cm2/(V·s) for 2,3,6,7,10,11-hexabutyloxytriphenylene (H4T), 2,3,6,7,10,11-hexapentyloxytriphenylene (H5T) and, 2,3,6,7,10,11-hexahexyloxytriphenylene (H6T), respectively. These are...
Herein, a series of asymmetric monoalkyl terthiophene derivatives, Ph-(Tp)<sub>3</sub>-C<italic>n</italic>, (6 ≤ <italic>n</italic> 18), were synthesized to study the phase transition from monolayered crystal bilayered crystal, leading significant increase OFET mobility.
Bias-stress effects in solution-processed, 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-10) field effect transistors (FETs) are studied under negative and positive direct current bias. The bottom gate, contact polycrystalline Ph-BTBT-10 FET with a hybrid gate dielectric of polystyrene SiO2 shows high mobility as well steep subthreshold slope when fabricated highly ordered smectic E liquid crystalline (SmE) film precursor. Negative bias-stress causes threshold voltage...
We have investigated the fabrication of polycrystalline thin films a liquid crystalline benzothienobenzothiophene derivative, i.e., 2-octylthienyl-benzothienobenzothiophene having highly ordered smectic crystal phase (SmE), thermal stability films, and performance their field effect transistors (FETs). The spin-coated at temperature SmE exhibited uniform textures were molecularly flat. FETs after solvent vapor anneal showed high FET mobility 1.1 cm2 V-1 s-1, while as-fabricated did low ca....