A molecular thermometer based on luminescence of copper(II) tetraphenylporphyrin

The photoluminescence (PL) spectra from solid samples consisting of polystyrene and 5,10,15,20-tetraphenyl-21H,23H-porphine copper(II) (CuTPP) revealed two sharp peaks at 653 and 720 nm, and indicated another broad peak at around 780 nm, which could not be observed in CuTPP solutions. The intensity ratio of the two peaks appearing at 653 nm and at around 780 nm demonstrated clear dependence on temperature. This dependence of the PL intensity ratio was observed under the atmosphere and even in water. The findings mean that we were able to utilize PL from CuTPP as a thermometer under various conditions. We measured the temperatures of an organic light-emitting diode (OLED) during operation based on its electroluminescence, where the OLED contained CuTPP as a light-emitting dopant, to demonstrate the CuTPP thermometer.ArticleThin Solid Films. 518(2):563-566 (2009)journal articl

Regulation of UDP-glucose:ceramide glucosyltransferase-1 by ceramide

AbstractWe report that the expression of mRNA and the activity of UDP-glucose:ceramide (Cer) glucosyltransferase-1 (GlcT-1) of human hepatoma Huh7 and mouse melanoma B16 cells increases after treatment with bacterial sphingomyelinase or upon addition of short-chain Cer. Interestingly, however, GlcT-1 gene transcription was not increased by Cer when GlcT-1 cDNA was introduced with the CMV promoter in GlcT-1-deficient GM95 cells, suggesting that the normal promoter region of GlcT-1 gene is essential for the response. The conversion of C6-Cer to C6-GlcCer occurred much more rapidly in GlcT-1-overexpressing Huh7 cells than in mock transfectants. As a result, GlcT-1-overexpressing cells acquired a greater resistance to C6-Cer-mediated cell death

Sensitization of organic photovoltaic cells based on interlayer excitation energy transfer

We incorporated an additional p-type organic semiconductor layer (APL) between the anode and the phthalocyanine layer, which is an indispensable p-type semiconductor layer (IPL) in forming a p/n junction with a fullerene C-60 layer. We used two thiophene/phenylene co-oligomers as the APL. The incorporation increases the short-circuit current density (J(SC)) and enhances incident photon-current conversion efficiency (IPCE) over the wavelength region where the APL shows strong absorption. Combined dependence of the APL/IPL implies that Forster resonance excitation transfer is the main factor in J(SC) and IPCE enhancements. We demonstrate clearly that the 'positive' hole injection barrier at the interface between the APL and the IPL impacts the smooth transportation of holes to the indium-tin-oxide anode. However, the small positive hole barrier of 0.1 eV has no noticeable influence on the fill factor of the current density versus voltage characteristic under photoirradiation, or on those devices with 'negative' hole barriers.ArticleOrganic Electronics. 11(4):700-704 (2010)journal articl

Effects of volatile additives in solutions used to prepare polythiophene-based thin-film transistors

We investigate the effects of volatile additives in solutions used to prepare thin-film transistors (TFTs) of regioregular poly(3-hexylthiophene) (P3HT). We use the additives trifluoromethylbenzene (TFMB) and methylcyclohexane (MCH) because they are poor solvents for P3HT. The additives improve the performance of the resulting TFTs when the boiling point (T(b)) of the major solvent, carbon tetrachloride, is lower than that of the additive. The maximum mobility is (4.0 +/- 60.9) x 10(-2) cm(2)V(-1)s(-1), which is 6.1 times larger than that of TFTs prepared without TFMB or MCH added to the solution; the on/off ratio and the subthreshold slope were also improved. The relative T(b) of the solvent and the additive affected the film formation with the amount of TFMB or MCH remaining at the final stage of thin film deposition influencing the precipitation of P3HT aggregates. (C) 2011 American Institute of Physics. [doi:10.1063/1.3553878]ArticleJOURNAL OF APPLIED PHYSICS. 109(5):54504 (2011)journal articl

チョウコウソク コウキノウ レーザー ナノ カコウ ソウチ ノ カイハツ ト シカヨウ ザイリョウ ノ カコウ

We proposed data recording on biological tissues and prostheses for personal identification. The data recording was performed by femtosecond laser processing with small thermal damage, a clear edge of recording point, and high data capacity. Because the biological tissues and the prostheses have unexpected movements and individual threedimensional shapes, the laser processing system was required to perform the recording with an adaptability and a high-throughput. The adaptability was implemented with a target surface detection system composed of an image sensor with a high-frame rate, a guide laser, and a piezoelectric transducer stage. The high-throughput was realized by parallel laser processing based on a computer-generated hologram displayed on a spatial light modulator. We demonstrate the data recording on dental prostheses. We also demonstrate parallel processing of glass using the holographic femtosecond laser processing

Bi- or ter-pyridine tris-substituted benzenes as electron-transporting materials for organic light-emitting devices

We demonstrated that 1,3,5-tris([2',2 '']bipyridin-6'-yl) benzene (BpyB) and 1,3,5-tris([ 2',2 '',6 '',2''']terpyridin-6'-yl)benzene (TpyB) are good electron-transport (ET) layer materials for organic light-emitting devices (OLEDs). The new materials exhibit high electron mobilities of around 10 (4) cm(2) V (1) s (1), and OLEDs comprising the materials operate at lower voltage than the OLEDs with tris(8-hydroxyquinolinato) aluminum (Alq) as an ET material. The new materials are also useful for phosphorescent OLEDs in blue-, green-, and red-light-emitting devices, where they function as both electron-transporting and hole-blocking materials. Phosphorescent OLEDs with the new materials operate at lower voltage (while maintaining comparable external quantum efficiencies of electroluminescence) than does the corresponding reference device with bathocuproine/Alq as electron-transporting and hole-blocking layers.ArticleORGANIC ELECTRONICS. 11(12):1966-1973 (2010)journal articl

Bipyridyl-substituted benzo[1,2,3]triazoles as a thermally stable electron transporting material for organic light-emitting devices

We developed new electron-transporting materials (ETMs) for organic light-emitting devices (OLEDs) based on benzo[1,2,3] triazole and two bipyridines. Four derivatives based on the same skeleton were synthesized with four different substituents: phenyl (BpyBTAZ-Ph), biphenyl (-BP), m-terphenyl (-mTP), and o-terphenyl (-oTP). These BpyBTAZ compounds have good thermal stabilities, and their decomposition temperatures were greater than 410 degrees C, which is significantly higher than that of tris(8-quinolinolato) aluminium (Alq), the conventional OLED material. BpyBTAZ compounds show preferable amorphous nature, and moreover, the glass transition temperatures (T(g)s) of both BpyBTAZ-TP compounds exceed 100 degrees C. Furthermore, BpyBTAZ-BP exhibits no melting point and is fully amorphous. The electron affinities of the materials are as large as 3.3 eV and their electron mobility is sufficiently high. These characteristics accounted for a reduction in the operational voltage of OLEDs with BpyBTAZ compounds compared with the reference device with Alq as an ETM. Specifically, the electron mobility of all the BpyBTAZ compounds exceeds 1 x 10(-4) cm(2) V(-1) s(-1) at an electric field of 1 MV cm(-1). In addition, it was revealed that both BpyBTAZ-TP-based devices showed longer luminous lifetimes and smaller voltage increases during continuous operation at 50 mA cm(-2), compared with the Alq reference device.ArticleJOURNAL OF MATERIALS CHEMISTRY. 21(32):11791-11799 (2011)journal articl

A highly efficient sublimation purification system using baffles with orifices

Here we report a highly efficient sublimation purification system using baffles with orifices in the sublimation tube. It is clearly demonstrated that the purity of materials is increased largely by introducing some pieces of baffles with orifices in the high-temperature region (sublimation region), which was confirmed by comparing the melting point (T-m) and the high-performance liquid chromatography (HPLC) purity with those of purified one by a conventional system. The driving voltages of electroluminescence (EL) devices were also compared and showed the same tendency with the T-m and HPLC purity data. Not only the purity but also the effective yield of purified materials was also increased by introducing baffles in low-temperature region. Some expected mechanisms of improving the purification efficiency by introducing baffles were also discussed.ArticleOrganic Electronics. 11(5):794-800 (2010)journal articl