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Yamasaki N.,Osaka University | Saito T.,Osaka University | Kim J.,Osaka University | Yoshida H.,Osaka University | And 3 more authors.
Thin Solid Films | Year: 2014

The monodomain growth of a columnar liquid crystalline (LC) semiconductor by a melt growth method has been studied. The domain growth of the LC phase of 1,4,8,11,15,18,22,25-octahexylphthalocyanine (C6PcH2) was observed by generating a temperature gradient on a cell at the temperature of LC-isotropic phase equilibrium. The large-area monodomain C6PcH2 in planar alignment was obtained by the method. The optical and electrical anisotropies in the oriented C6PcH2 were investigated and discussed by taking the column alignment into consideration. © 2013 Elsevier B.V.

Miyake Y.,Research Institute for Ubiquitous Energy Devices | Miyake Y.,Osaka University | Shiraiwa Y.,Research Institute for Ubiquitous Energy Devices | Okada K.,Research Institute for Ubiquitous Energy Devices | And 8 more authors.
Applied Physics Express | Year: 2011

Carrier transport properties of a non-peripherally alkyl-substituted phthalocyanine, 1,4,8,11,15,18,22,25-octahexylphthalocyanine (C6PcH2) have been investigated. The material is a low-molecular-weight organic semiconductor with high solubility for typical organic solvents and liquid crystallinity. The carrier mobility was measured in the crystal phase and the hexagonal disordered columnar (Colhd) mesophase by the time-of-flight technique. A strong negative temperature dependence was observed for the hole mobility in the crystal phase, and a maximum drift mobility of 1.4 cm 2·V-1·s-1 was achieved at - 15 °C. A maximum mobility of 0.5 cm2·V -1·s-1 was obtained for the electrons that had a smaller dependence. © 2011 The Japan Society of Applied Physics.

Hori T.,Osaka University | Miyake Y.,Osaka University | Miyake Y.,Research Institute for Ubiquitous Energy Devices | Yamasaki N.,Osaka University | And 4 more authors.
Applied Physics Express | Year: 2010

Organic thin-film solar cells based on a bulk heterojunction utilizing the phthalocyanine derivative 1,4,8,11,15,18,22,25-octahexylphthalocyanine (C6PcH2) have been studied. C6PcH2 is soluble in common organic solvents such as chloroform, and the blend uniform thin film with the fullerene derivative 1-(3-methoxy-carbonyl)-propyl-1-1-phenyl-(6,6)C61 (PCBM) could be fabricated by a spin-coating method. Solar cells with an indium- tin-oxide/polymer hole transport layer/C6PcH2:PCBM/Al structure, the active layer of which was prepared by a wet process using a low-weighted molecular system, have demonstrated a high external quantum efficiency of more than 70% in the Q-band absorption region of C6PcH2 and a high energy conversion efficiency of 3.1%. © 2010 The Japan Society of Applied Physics.

Umezawa H.,Research Institute for Ubiquitous Energy Devices | Shikata S.,Research Institute for Ubiquitous Energy Devices | Shibata H.,Research Center for Photovoltaic Technologies | Imanishi T.,Molecular Profiling Research Center for Drug Discovery | And 8 more authors.
AIST Today (International Edition) | Year: 2013

Diamond is receiving much attention due to its outstanding properties as a power semiconductor material. The new buffer layer is a ZnMgO alloy fabricated by the sputtering method. Advantages of the new method are that ZnMgo is Cd-free and hence is effective to reduce the environmental load and the sputtering method is a dry process which is simple compared to wet processes. The conversion efficiency of the CIGS solar cell using the new buffer layer is 17.5%, which is comparable to that of CIGS solar cells using a conventional CdS buffer layer fabricated by wet processes. Interspecies hybridization after the speciation between humans and chimpanzees has been heated controversy in evolutionary biology. The estimated values varied significantly among chromosomes, the X chromosome being the smallest value, but the variation could be explained by the variation of mutation rates among chromosomes, not by the variation of divergence times.

Sosa-Vargas L.,Research Institute for Ubiquitous Energy Devices | Nekelson F.,Research Institute for Ubiquitous Energy Devices | Okuda D.,Research Institute for Ubiquitous Energy Devices | Okuda D.,Ryukoku University | And 7 more authors.
Journal of Materials Chemistry C | Year: 2015

Two new perfluoroalkylated phthalocyanine derivatives were synthesised and characterised in order to investigate the effects of the fluorophobic/fluorophilic interactions on their mesophase and electronic properties. Both compounds exhibit columnar mesomorphism and the thermal stability of the columnar phase is enhanced by over 20 °C as the number of fluorinated carbons increases, probably due to the nano-segregation between the fluorinated and hydrocarbon moieties in the chains. Also a strong tendency towards spontaneous homeotropic alignment was observed. Time of Flight (ToF) measurements were carried out to reveal the mobility characteristics and the ambipolar mobility was measured in the order of 10-1 to 10-2 cm2 V-1 s-1 for the mesophases. © 2015 The Royal Society of Chemistry.

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