研究者詳細 - 小山　剛史

Excitation Energy Transfer by Electron Exchange via Two-Step Electron Transfer between a Single-Walled Carbon Nanotube and Encapsulated Magnesium Porphyrin 査読有り

Koyama Takeshi*, Junpei Sugiura, Tomonari Koishi, Ryosuke Ohashi, Koji Asaka, Takeshi Saito, Yanlin Gao, Susumu Okada, Hideo Kishida

JOURNAL OF PHYSICAL CHEMISTRY C 124 巻 ( 35 ) 頁： 19406 - 19412 2020年9月

Isolation of Single-Wired Transition-Metal Monochalcogenides by Carbon Nanotubes 査読有り

Masataka Nagata, Shivani Shukla, Yusuke Nakanishi, Zheng Liu, Yung-Chang Lin, Takuma Shiga, Yuto Nakamura, Takeshi Koyama, Hideo Kishida, Tsukasa Inoue, Naoyuki Kanda, Shun Ohno, Yuki Sakagawa, Kazu Suenaga, Hisanori Shinohara

NANO LETTERS 19 巻 ( 8 ) 頁： 4845 - 4851 2019年8月

Acceleration of Photocarrier Relaxation in Graphene Achieved by Epitaxial Growth: Ultrafast Photoluminescence Decay of Monolayer Graphene on SiC 査読有り

Imaeda, H; Koyama, T; Kishida, H; Kawahara, K; Ago, H; Sakakibara, R; Norimatsu, W; Terasawa, T; Bao, JF; Kusunoki, M

JOURNAL OF PHYSICAL CHEMISTRY C 122 巻 ( 33 ) 頁： 19273 - 19279 2018年8月

Energetics and electronic structures of perylene confined in carbon nanotubes 査読有り

Nagasawa, Y; Koyama, T; Okada, S

ROYAL SOCIETY OPEN SCIENCE 5 巻 ( 6 ) 頁： 180359-1 - 180359-9 2018年6月

Different Molecular Arrangement of Perylene in Metallic and Semiconducting Carbon Nanotubes: Impact of van der Waals Interaction 査読有り

Koyama, T; Fujiki, K; Nagasawa, Y; Okada, S; Asaka, K; Saito, Y; Kishida, H

JOURNAL OF PHYSICAL CHEMISTRY C 122 巻 ( 10 ) 頁： 5805 - 5812 2018年3月

Facile Synthetic Route to Atomically Thin Conductive Wires from Single-Species Molecules in One-Dimensionally Confined Space: Doped Conjugated Polymers inside Single-Walled Carbon Nanotubes 査読有り

Sasaki, M; Koyama, T; Kishida, H; Asaka, K; Saito, Y; Yoshida, Y; Saito, G

JOURNAL OF PHYSICAL CHEMISTRY LETTERS 8 巻 ( 8 ) 頁： 1702 - 1706 2017年4月

Hydrogen-surfactant-mediated epitaxy of Ge_1-xSn_x layer and its effects on crystalline quality and photoluminescence property 査読有り

Osamu Nakatsuka*, Shunsuke Fujinami, Takanori Asano, Takeshi Koyama, Masashi Kurosawa, Mitsuo Sakashita, Hideo Kishida, and Shigeaki Zaima

Japanese Journal of Applied Physics 56 巻 ( 1S ) 頁： 01AB05-1 - 01AB05-6 2017年1月

Hydrogen-surfactant-mediated epitaxy of Ge1-xSnx layer and its effects on crystalline quality and photoluminescence property

Nakatsuka, O; Fujinami, S; Asano, T; Koyama, T; Kurosawa, M; Sakashita, M; Kishida, H; Zaima, S

JAPANESE JOURNAL OF APPLIED PHYSICS 56 巻 ( 1 ) 2017年1月

Two-Step Excitation Triggered by One-Photon Absorption on Linear Dispersion in Monolayer Graphene 査読有り

Takeshi Koyama*, Kenta Mizutani, Hiroki Ago, and Hideo Kishida

The Journal of Physical Chemistry C 120 巻 ( 20 ) 頁： 11225 - 11229 2016年5月

Near-Infrared Photoluminescence Properties of Endohedral Mono- and Dithulium Metallofullerenes 査読有り

Zhiyong Wang, Noriko Izumi, Yusuke Nakanishi, Takeshi Koyama, Toshiki Sugai, Masayoshi Tange, Toshiya Okazaki, and Hisanori Shinohara*

ACS Nano 10 巻 ( 4 ) 頁： 4282 - 4287 2016年4月

Ultrafast Energy Transfer from Fluorene Polymers to Single-Walled Carbon Nanotubes in Wrapped Carbon Nanotube Bundles 査読有り

Arao Nakamura*, Takeshi Koyama, Yasumitsu Miyata, and Hisanori Shinohara

The Journal of Physical Chemistry C 120 巻 ( 8 ) 頁： 4647 - 4652 2016年3月

Ultrafast excitation energy transfer from encapsulated quaterrylene to single-walled carbon nanotube 査読有り

Takeshi Koyama*, Takuya Tsunekawa, Takeshi Saito, Koji Asaka, Yahachi Saito, Hideo Kishida, and Arao Nakamura

Journal of Luminescence 169 巻 ( B ) 頁： 645 - 648 2016年1月

Photoluminescence of poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) in the visible region 査読有り

Takeshi Koyama*, Taiki Matsuno, Yasunori Yokoyama, and Hideo Kishida

Journal of Materials Chemistry C 3 巻 ( 32 ) 頁： 8307 - 8310 2015年8月

Synthesis and Photophysics of Quaterrylene Molecules in Single-Walled Carbon Nanotubes: Excitation Energy Transfer between a Nanoscale Cylinder and Encapsulated Molecules 査読有り

Takeshi Koyama*, Takuya Tsunekawa, Takeshi Saito, Koji Asaka, Yahachi Saito, Hideo Kishida, and Arao Nakamura

The Journal of Physical Chemistry C 118 巻 ( 37 ) 頁： 21671-21681 2014年9月

Microscopic Mobility of Polarons in Chemically Doped Polythiophenes Measured by Employing Photoluminescence Spectroscopy 査読有り

Takeshi Koyama*, Arao Nakamura, and Hideo Kishida

ACS Photonics 1 巻 ( 8 ) 頁： 655-661 2014年8月

Trion dynamics in hole-doped single-walled carbon nanotubes 査読有り

Arao Nakamura*, Satoru Shimizu, Takeshi Koyama, Yasumitsu Miyata, and Hisanori Shinohara

AIP Conference Proceedings 1566 巻頁： 163-164 2013年12月

Dynamics of photoexcited carriers in monolayer epitaxial graphene probed by photoluminescence in the near-infrared region 査読有り

Takeshi Koyama*, Yoshito Ito, Kazuma Yoshida, Hiroki Ago, and Arao Nakamura

AIP Conference Proceedings 1566 巻頁： 167-168 2013年12月

Transient Absorption Kinetics Associated with Higher Exciton States in Semiconducting Single-Walled Carbon Nanotubes: Relaxation of Excitons and Phonons 査読有り

Takeshi Koyama*, Shohei Yoshimitsu, Yasumitsu Miyata, Hisanori Shinohara, Hideo Kishida, and Arao Nakamura

The Journal of Physical Chemistry C 117 巻 ( 39 ) 頁： 20289-20299 2013年10月

Ultrafast formation and decay dynamics of trions in p-doped single-walled carbon nanotubes 査読有り

Takeshi Koyama*, Satoru Shimizu, Yasumitsu Miyata, Hisanori Shinohara, and Arao Nakamura

Physical Review B 87 巻 ( 16 ) 頁： 165430/1-6 2013年4月

Near-Infrared Photoluminescence in the Femtosecond Time Region in Monolayer Graphene on SiO₂ 査読有り

Takeshi Koyama*, Yoshito Ito, Kazuma Yoshida, Masaharu Tsuji, Hiroki Ago, Hideo Kishida, and Arao Nakamura

ACS Nano 7 巻 ( 3 ) 頁： 2335-2343 2013年3月

Photophysics in Single-Walled Carbon Nanotubes with (6,4) Chirality at High Excitation Densities: Bimolecular Auger Recombination and Phase-Space Filling of Excitons 査読有り

Takeshi Koyama*, Yasumitsu Miyata, Hideo Kishida, Hisanori Shinohara, and Arao Nakamura

The Journal of Physical Chemistry C 117 巻 ( 4 ) 頁： 1974-1981 2013年1月

Ultrafast energy transfer of one-dimensional excitons between carbon nanotubes: a femtosecond time-resolved luminescence study 招待有り査読有り

Takeshi Koyama*, Yasumitsu Miyata, Koji Asaka, Hisanori Shinohara, Yahachi Saito, and Arao Nakamura

Physical Chemistry Chemical Physics 14 巻 ( 3 ) 頁： 1070-1084 2012年1月

Ultrafast luminescence kinetics of metallic single-walled carbon nanotubes: Possible evidence for excitonic luminescence 査読有り

Takeshi Koyama*, Satoru Shimizu, Takeshi Saito, Yasumitsu Miyata, Hisanori Shinohara, and Arao Nakamura

Physical Review B 85 巻 ( 4 ) 頁： 045428/1-7 2012年1月

Exciton Energy Transfer between Single-Walled Carbon Nanotubes in Femtosecond Regime 査読有り

Takeshi Koyama*, Koji Asaka, Naoki Hikosaka, Hideo Kishida, Yahachi Saito, and Arao Nakamura

AIP Conference Proceedings 1399 巻頁： 759-760 2011年12月

Enhancement of Third-Order Optical Nonlinearities in Carbon Nanotubes by Encapsulated Fullerenes 査読有り

D. Hosooka, T. Koyama, H. Kishida, K. Asaka, Y. Saito, T. Saito, and A. Nakamura*

AIP Conference Proceedings 1399 巻頁： 831-832 2011年12月

Ultrafast Exciton Energy Transfer between Nanoscale Coaxial Cylinders: Intertube Transfer and Luminescence Quenching in Double-Walled Carbon Nanotubes 査読有り

Takeshi Koyama*, Yuki Asada, Naoki Hikosaka, Yasumitsu Miyata, Hisanori Shinohara, and Arao Nakamura

ACS Nano 5 巻 ( 7 ) 頁： 5881-5887 2011年7月

Dynamics of nuclear wave packets at the F center in alkali halides 査読有り

Takeshi Koyama* and Tohru Suemoto

Reports on Progress in Physics 74 巻 ( 7 ) 頁： 076502/1-22 2011年7月

Femtosecond luminescence decay due to exciton energy transfer in single-walled carbon nanotube bundles 査読有り

Takeshi Koyama*, Koji Asaka, Naoki Hikosaka, Hideo Kishida, Yahachi Saito, and Arao Nakamura

Journal of Luminescence 131 巻 ( 3 ) 頁： 494-497 2011年3月

Ultrafast Exciton Energy Transfer in Bundles of Single-Walled Carbon Nanotubes 査読有り

Takeshi Koyama*, Koji Asaka, Naoki Hikosaka, Hideo Kishida, Yahachi Saito, and Arao Nakamura

The Journal of Physical Chemistry Letters 2 巻 ( 3 ) 頁： 127-132 2011年2月

Bright Luminescence and Exciton Energy Transfer in Polymer-Wrapped Single-Walled Carbon Nanotube Bundles 査読有り

Takeshi Koyama*, Yasumitsu Miyata, Yuki Asada, Hisanori Shinohara, Hiromichi Kataura, and Arao Nakamura

The Journal of Physical Chemistry Letters 1 巻頁： 3243-3248 2010年11月

Observation of nuclear wave packets in the excited state of the F center in alkali halides 査読有り

Takeshi Koyama*, Makoto Nakajima, and Tohru Suemoto

Journal of Luminescence 129 巻 ( 12 ) 頁： 1435-1440 2009年12月

Femtosecond Depolarization of Hot Luminescence from the F Center in KCl 査読有り

Takeshi Koyama*, Makoto Nakajima, Tohru Suemoto

Journal of the Physical Society of Japan 78 巻 ( 7 ) 頁： 075002/1-2 2009年7月

Second 2s-2p level crossing at the F center in KCl evidenced by frequency up-conversion spectroscopy 査読有り

Takeshi Koyama*, Makoto Nakajima, and Tohru Suemoto

Physical Review B 79 巻 ( 19 ) 頁： 193103/1-4 2009年5月

Dynamics of nuclear wave packet in the excited state of KCl F centers 査読有り

Takeshi Koyama*, Makoto Nakajima, and Tohru Suemoto

Physica Status Solidi (c) 6 巻 ( 1 ) 頁： 108-111 2009年1月

Observation of nuclear wave packet oscillations at the F center in KCl and RbCl 査読有り

Takeshi Koyama*, Makoto Nakajima, and Tohru Suemoto

Physical Review B 78 巻 ( 15 ) 頁： 155126/1-5 2008年10月

Nuclear wave-packet dynamics on nearly degenerate two adiabatic potential energy surfaces in the excited state of KI F centers 査読有り