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6. Near-infrared photoluminescence from molecular crystals containing tellurium

Author

Sun, Hong-Tao, Sakka, Yoshio, Shirahata, Naoto, Fujii, Minoru, and Yonezawa, Tetsu

Subjects
Condensed Matter - Materials Science
Abstract

We report the observation of near-infrared photoluminescence from Te4(Ga2Cl7)2 and Te4(Al2Cl7)2 molecular crystals containing Te42+ polycations. The experimental and theoretical results clearly revealed that Te42+ polycation is one smart near-infrared emitter with characteristic emission peaks at 1252 and 1258 nm for Te4(Ga2Cl7)2 and Te4(Al2Cl7)2 crystals, respectively, resulting from the intrinsic electronic transitions of Te42+. Furthermore, it was also found that the emissions strongly depend on the excitation wavelengths for both Te4(Ga2Cl7)2 and Te4(Al2Cl7)2 samples, most possibly owing to the co-existence of other Te-related optically active centers. This research not only enriches the species of luminescent charged p-block element polyhedra and deepens the understanding of Te-related photophysical behaviors, but also may stimulate efforts for designing novel material systems using such active centers. It is also greatly expected that these sub-nanometer optically active species could exist in other systems such as glasses, polymers, and bulk optical crystals, and the stabilization of these centers in widely used hosts will pave the way for their practical applications.

Published
2012
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7. Photoluminescence from Bi5(GaCl4)3 molecular crystal

Author

Sun, Hong-Tao, Xu, Beibei, Yonezawa, Tetsu, Sakka, Yoshio, Shirahata, Naoto, Fujii, Minoru, Qiu, Jianrong, and Gao, Hong

Subjects
Condensed Matter - Materials Science
Abstract

Bi5(GaCl4)3 sample has been synthesized through the oxidation of Bi metal by gallium chloride (GaCl3) salt. Powder X-ray diffraction as well as micro-Raman scattering results revealed that, in addition to crystalline Bi5(GaCl4)3 in the product, amorphous phase containing [GaCl4]- and [Ga2Cl7]- units also exist. The thorough comparison of steady-state and time-resolved photoluminescent behaviors between Bi5(GaCl4)3 product and Bi5(AlCl4)3 crystal leads us to conclude that Bi53+ is the dominant emitter in the product, which gives rise to the ultrabroad emission ranging from 1 to 2.7 micrometer. Detailed quantum chemistry calculation helps us assign the observed excitations to some electronic transitions of Bi53+ polycation, especially at shorter wavelengths. It is believed that our work shown here not only is helpful to solve the confusions on the luminescent origin of bismuth in other material systems, but also serves to develop novel broadband tunable laser materials.

Published
2012
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8. Ultra-broad near-infrared photoluminescence from crystalline (K-crypt)2Bi2 containing [Bi2]2- dimers

Author

Sun, Hong-Tao, Yonezawa, Tetsu, Gillett-Kunnath, Miriam M., Sakka, Yoshio, Shirahata, Naoto, Gui, Sa Chu Rong, Fujii, Minoru, and Sevov, Slavi C.

Subjects
Condensed Matter - Materials Science
Abstract

For the first time, we report that a single crystal of (K-crypt)2Bi2 containing [Bi2]2+ displays ultra-broad near-infrared photoluminescence (PL) peaking at around 1190 nm and having a full width at the half maximum of 212 nm, stemming from the inherent electronic transitions of [Bi2]2+.The results not only add to the number of charged Bi species with luminescence, but also deepen the understanding of Bi-related near-infrared emission behavior and lead to the reconsideration of the fundamentally important issue of Bi-related PL mechanisms in some material systems such as bulk glasses, fibers, and conventional optical crystals.

Published
2012
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9. Experimental and Theoretical Studies of Photoluminescence from Bi82+ and Bi53+ stabilized by [AlCl4]- in Molecular Crystals

Author

Sun, Hong-Tao, Sakka, Yoshio, Shirahata, Naoto, Gao, Hong, and Yonezawa, Tetsu

Subjects
Condensed Matter - Materials Science
Abstract

The photophysical properties of Bi82+ and Bi53+ polycations stabilized by [AlCl4]- have been studied experimentally and theoretically. The obtained product was thoroughly evaluated by powder X-ray diffraction and photoluminescence spectroscopy, making it clear that both Bi82+ and Bi53+ contribute to the observed broad near-infrared emission. Furthermore, it was revealed that Bi82+ polycation mainly results in the emission peaking at ca. 1180 nm, while Bi53+ the longer-wavelength emission. The following quantum chemistry calculation on Bi82+ polycation helps us attribute some observed excitation bands in the visible spectral range to specific electronic transitions of bismuth polycations. It is believed that systematical investigation of structural and luminescent properties as well as detailed quantum chemistry calculation of molecular crystals containing such kinds of bismuth units allows us to obtain a clearer picture on bismuth-related photophysical behaviors, which not only serve to solve the confusions on the luminescence origin of bismuth in other material systems such as bulk glasses, glass fibers and conventional crystals, but also is helpful to develop novel applicable broadband tunable laser mediums.

Published
2012
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10. Hybrid hydrogels containing vertically aligned carbon nanotubes with anisotropic electrical conductivity for muscle myofiber fabrication.

Author

Ahadian, Samad, Ramón-Azcón, Javier, Estili, Mehdi, Liang, Xiaobin, Ostrovidov, Serge, Shiku, Hitoshi, Ramalingam, Murugan, Nakajima, Ken, Sakka, Yoshio, Bae, Hojae, Matsue, Tomokazu, and Khademhosseini, Ali

Subjects
Myoblasts, Animals, Mice, Nanotubes, Carbon, Muscle Proteins, Gelatin, Hydrogels, Electrophoresis, Cell Culture Techniques, Tissue Engineering, Electric Stimulation, Cell Differentiation, Cell Survival, Gene Expression, Electric Conductivity, Anisotropy, Tissue Scaffolds, Muscle Fibers, Skeletal, Nanotubes, Carbon, Muscle Fibers, Skeletal
Abstract

Biological scaffolds with tunable electrical and mechanical properties are of great interest in many different fields, such as regenerative medicine, biorobotics, and biosensing. In this study, dielectrophoresis (DEP) was used to vertically align carbon nanotubes (CNTs) within methacrylated gelatin (GelMA) hydrogels in a robust, simple, and rapid manner. GelMA-aligned CNT hydrogels showed anisotropic electrical conductivity and superior mechanical properties compared with pristine GelMA hydrogels and GelMA hydrogels containing randomly distributed CNTs. Skeletal muscle cells grown on vertically aligned CNTs in GelMA hydrogels yielded a higher number of functional myofibers than cells that were cultured on hydrogels with randomly distributed CNTs and horizontally aligned CNTs, as confirmed by the expression of myogenic genes and proteins. In addition, the myogenic gene and protein expression increased more profoundly after applying electrical stimulation along the direction of the aligned CNTs due to the anisotropic conductivity of the hybrid GelMA-vertically aligned CNT hydrogels. We believe that platform could attract great attention in other biomedical applications, such as biosensing, bioelectronics, and creating functional biomedical devices.

Published
2014

13. Ti2AlN配向体の摩耗特性

Author

SAKKA, Yoshio, primary, MUSHA, Shotaro, additional, MORITA, Kouji, additional, KASAHARA, Akira, additional, TOSA, Masahiro, additional, and SUZUKI, Tohru S., additional

Published
2023
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19. Dense lanthanum silicate oxyapatite ceramics obtained by uniaxial pressing and slip casting

Author

Toja Ramiro Moreira, Rendtorffa Nicolás M., Agliettia Esteban F., Uchikoshi Tetsuo, Sakka Yoshio, and Suáreza Gustavo

Subjects
apatite-type lanthanum silicates, uniaxial pressing, slip casting, sintering, microstructure, Chemical technology, TP1-1185
Abstract

Lanthanum silicate oxyapatite (LSO) is a promising ion conductive ceramic material, which has higher oxygen ion conductivity at intermediate temperatures (600-800°C) compared to yttria-stabilized zirconia. Its mechanical properties, though important for any of its applications, have been scarcely reported. In this study, we compare apparent densification, open porosity and Vickers hardness of samples conformed by uniaxial pressing and slip casting and fired up to 1600°C. Colloidal processing was optimized for slip casting in order to get high green densities. At sintering temperatures higher than 1400ºC, both processing routes yielded comparable densities, although uniaxially pressed samples show slightly better mechanical properties, evidencing that slip cast ones already underwent a grain growth process.

Published
2018
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36. List of Contributors

Author

Abe, Hiroya, primary, Adschiri, Tadafumi, additional, Aida, Tsutomu, additional, Akatsu, Takashi, additional, Akedo, Jun, additional, Ando, Masanori, additional, Ando, Yoshinori, additional, Anzai, Hiroyuki, additional, Aoki, Nobuaki, additional, Awano, Masanobu, additional, Azushima, Akira, additional, Baba, Tetsuya, additional, Chen, Weiwu, additional, Ehara, Kensei, additional, Emi, Hitoshi, additional, Fudouzi, Hiroshi, additional, Fuji, Masayoshi, additional, Fujii, Hidetoshi, additional, Fukui, Hiroshi, additional, Fukui, Takehisa, additional, Fukumori, Yoshinobu, additional, Goda, Hideki, additional, Gotoh, Kuniaki, additional, Hakuta, Yukiya, additional, Hara, Kaori, additional, Hayashi, Akitoshi, additional, Hayashi, Kazuyuki, additional, Higashitani, Ko, additional, Hirao, Kazuyuki, additional, Hojo, Daisuke, additional, Hosokawa, Kouhei, additional, Hosokawa, Masuo, additional, Hotta, Yuji, additional, Ichikawa, Hideki, additional, Ida, Takashi, additional, Ihara, Manabu, additional, Iijima, Motoyuki, additional, Imai, Yusuke, additional, Inagaki, Shinji, additional, Inoue, Mitsuteru, additional, Iritani, Eiji, additional, Iriyama, Yasutoshi, additional, Ishida, Naoyuki, additional, Ishii, Toshihiro, additional, Isu, Norifumi, additional, Iwata, Mikimasa, additional, Jinnai, Hiroshi, additional, Jiu, Jinting, additional, Kaga, Norihiko, additional, Kajikawa, Kotaro, additional, Kakui, Toshio, additional, Kamiya, Hidehiro, additional, Kaneko, Kenji, additional, Kanie, Kiyoshi, additional, Kano, Junya, additional, Kasai, Hitoshi, additional, Kasuga, Tomoko, additional, Katamoto, Tsutomu, additional, Katsura, Shinji, additional, Kawahara, Masayoshi, additional, Kawashima, Yoshiaki, additional, Kinemuchi, Yoshiaki, additional, Kirihara, Soshu, additional, Koshimizu, Masanori, additional, Kondo, Akihiko, additional, Kondo, Akira, additional, Kondou, Katsuyoshi, additional, Kozawa, Takahiro, additional, Kurihara, Kazue, additional, Kuroda, Shun'ichi, additional, Kurumada, Ken-ichi, additional, Kuwahara, Hiroaki, additional, Li, Chunliang, additional, Makino, Hisao, additional, Maruo, Shoji, additional, Masuda, Hiroaki, additional, Masuda, Yoshitake, additional, Matsuda, Motohide, additional, Matsusaka, Shuji, additional, Matsuyama, Tatsushi, additional, Mezaki, Reiji, additional, Mikayama, Takeshi, additional, Miyahara, Minoru, additional, Miyajima, Kiyotomi, additional, Miyamoto, Yoshinari, additional, Miyayama, Masaru, additional, Miyazaki, Hideki T., additional, Mori, Hidetoshi, additional, Morimoto, Tsutomu, additional, Morita, Kenta, additional, Munakata, Hirokazu, additional, Muto, Hiroyuki, additional, Munir, Muhammad M., additional, Muramatsu, Atsushi, additional, Murase, Norio, additional, Myojo, Toshihiko, additional, Naito, Makio, additional, Nakajima, Noriyuki, additional, Nakamoto, Masami, additional, Nakamura, Masaharu, additional, Nakamura, Keitaro, additional, Nakanishi, Hachiro, additional, Namiki, Norikazu, additional, Nishimura, Yuya, additional, Noda, Naoki, additional, Nogi, Kiyoshi, additional, Noguchi, Yuji, additional, Noma, Junichi, additional, Nomura, Toshiyuki, additional, Ogi, Takashi, additional, Ogino, Chiaki, additional, Ohara, Satoshi, additional, Ohtomo, Akira, additional, Oikawa, Hidetoshi, additional, Okamoto, Tomoichiro, additional, Okubo, Tatsuya, additional, Okuyama, Kikuo, additional, Osada, Minoru, additional, Otani, Yoshio, additional, Otsubo, Yasufumi, additional, Otsuki, Masashi, additional, Saito, Fumio, additional, Sakaguchi, Shuji, additional, Sakka, Yoshio, additional, Sasabe, Shuji, additional, Sasai, Aiko, additional, Sasaki, Takayoshi, additional, Sasaki, Takafumi, additional, Satoh, Norifusa, additional, Senda, Tetsuya, additional, Seong, Gimyeong, additional, Setsuhara, Yuichi, additional, Shikano, Haruhide, additional, Shimada, Manabu, additional, Suda, Akihiko, additional, Suganuma, Katsuaki, additional, Suzuki, Hisao, additional, Suzuki, Michitaka, additional, Suzuki, Takahiro, additional, Takada, Takahiro, additional, Takahashi, Chisato, additional, Takai, Chika, additional, Takami, Seiichi, additional, Takase, Hirofumi, additional, Takebayashi, Kenji, additional, Takeuchi, Hirofumi, additional, Tatami, Junichi, additional, Tatsumisago, Masahiro, additional, Toda, Kenji, additional, Togashi, Takanari, additional, Tojo, Tetsuro, additional, Tomai, Takaaki, additional, Tsujimoto, Hiroyuki, additional, Tsukada, Takao, additional, Tsukada, Yusuke, additional, Uchikoshi, Tetsuo, additional, Uematsu, Keizo, additional, Ueshima, Minoru, additional, Umetsu, Mitsuo, additional, Usuki, Arimitsu, additional, Wakai, Fumihiro, additional, Wei, Xing, additional, Yamaguchi, Akimasa, additional, Yamaguchi, Yukio, additional, Yamamoto, Hiromitsu, additional, Yamamoto, Kenji, additional, Yamamoto, Kimihisa, additional, Yamamoto, Atsushi, additional, Yashima, Masatomo, additional, Yoko, Akira, additional, Yokoi, Atsushi, additional, Yokoyama, Toyokazu, additional, Yonezawa, Susumu, additional, Yonezawa, Tetsu, additional, and Zhang, Qiwu, additional

Published
2018
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44. Fabrication of Textured Porous Ti3SiC2 by Slip Casting under High Magnetic Field and Microstructural Evolution through High Temperature Deformation

Author

Hashimoto, Nana, Ikeda, Ken-ichi, Miura, Seiji, Morita, Koji, Suzuki, Tohru S., and Sakka, Yoshio

Subjects
high magnetic field, porous material, Ti3SiC2, texture, kink deformation
Abstract

To clarify the effect of constraint conditions on the kink formation, fabrication process of the texture and porosity controlled Ti3SiC2 polycrystals was investigated and microstructural evolution during high temperature deformation was examined in it under high temperature uniaxial compression tests at 1200 degrees C. Dense textured Ti3SiC2 sintered body was fabricated by slip casting in the high magnetic field of 12 T and following pressureless sintering at 1400 degrees C for 1 h. The porosity of the textured Ti3SiC2 was controlled by dispersing polymethyl methacrylate (PMMA) particles into the textured Ti3SiC2 as a spacer media. The highly textured Ti3SiC2 polycrystals with porosity of 8.4 vol% and 16.7 vol%, respectively, were successfully fabricated by the slip casting in the high magnetic field. After the high temperature uniaxial compression perpendicular to the c-axis of the textured structure, both the porous and dense Ti3SiC2 showed kink formation, which is a common deformation mode for anisotropic layered materials. However, the average rotation angles of the kink boundaries were higher in the porous specimen than in the dense specimen. Since the crystal rotation is necessary for the kink formation, kink bands would be preferably developed in the porous area due to its weaker constraint than in the dense area. It can be concluded from the microstructural analysis that the constrain factor caused by the neighbor grains affects the crystalline rotation, resulting in the kink boundary formation with different rotation angles.

Published
2022

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