Hideaki Komiyama

Instituto de Investigaciones Químicas

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Takuma Yasuda

Kyoto University

Tomokazu Iyoda

Doshisha University

Motonori Komura

National Institute of Technology, Numazu College

Seiichi Furukawa

Kyushu University

Tatsuya Oyama

Kyoto Pharmaceutical University

Takahiro Ichikawa

Tokyo University of Agriculture and Technology

Kaori Kamata

National Defense Medical College

Keiji Nagai

Osaka University

Chihaya Adachi

Kyushu University

Tatsuya Mori

Kyushu University

Cooperative Institutions

Tokyo Institute of Technology

Japan Science and Technology Agency

The University of Tokyo

Kyushu University

Osaka University

Kyoto University

Tohoku University

National Institute of Advanced Industrial Science and Technology

Nagoya University

Instituto de Investigaciones Químicas

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CCDC 1545555: Experimental Crystal Structure Determination

The Cambridge Structural Database (2017)

Tatsuya Mori Tatsuya Oyama Hideaki Komiyama Takuma Yasuda

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

10.5517/ccdc.csd.cc1nw8mf

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Citations (0)

Metal nanodot arrays fabricated via seed-mediated electroless plating with block copolymer thin film scaffolding

Nanotechnology (2015)

Hideaki Komiyama Tomokazu Iyoda Takanobu Sanji

We present an alternative approach to fabricating hexagonally arranged nanodot arrays of various metals by seed-mediated electroless plating with a cylinder-forming block copolymer thin film, PEO-b-PMA(Az), as a scaffold. Metal ions were selectively incorporated into PEO cylinders, followed by their reduction to metal and the etching of the scaffold to obtain highly ordered seed arrays of Au, Pd, and Pt. Nanodot arrays of the target metals (Au, Ag, and Ni) were selectively grown on the seed with their highly ordered arrangement by electroless plating. We studied the fabrication processes' suitability for control of the nanodot array size, as well as the plasmonic properties thereof.

Nanodot

Plating (geology)

10.1088/0957-4484/26/39/395302

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Citations (3)

Star-shaped and linear π-conjugated oligomers consisting of a tetrathienoanthracene core and multiple diketopyrrolopyrrole arms for organic solar cells

Beilstein Journal of Organic Chemistry (2016)

Hideaki Komiyama Chihaya Adachi Takuma Yasuda

Solution-processable star-shaped and linear π-conjugated oligomers consisting of an electron-donating tetrathienoanthracene (TTA) core and electron-accepting diketopyrrolopyrrole (DPP) arms, namely, TTA-DPP4 and TTA-DPP2, were designed and synthesized. Based on density functional theory calculations, the star-shaped TTA-DPP4 has a larger oscillator strength than the linear TTA-DPP2, and consequently, better photoabsorption property over a wide range of visible wavelengths. The photovoltaic properties of organic solar cells based on TTA-DPP4 and TTA-DPP2 with a fullerene derivative were evaluated by varying the thickness of the bulk heterojunction active layer. As a result of the enhanced visible absorption properties of the star-shaped π-conjugated structure, better photovoltaic performances were obtained with relatively thin active layers (40–60 nm).

Active layer

Derivative (finance)

10.3762/bjoc.12.142

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Citations (5)

High-Performance Organic Energy-Harvesting Devices and Modules for Self-Sustainable Power Generation under Ambient Indoor Lighting Environments

ACS Applied Materials & Interfaces (2019)

Ryota Arai Seiichi Furukawa Yu Hidaka Hideaki Komiyama Takuma Yasuda

Organic photovoltaics (OPVs) that perform more efficiently under artificial indoor lighting conditions than they do under sunlight are attracting growing interest as they can potentially serve as ambient energy harvesters for powering low-power electronics and portable devices for the Internet of Things. Herein, solution-processed small-molecule OPVs are demonstrated to exhibit high power conversion efficiencies exceeding 16% under white LED illumination, delivering high output power densities of up to 12.4 and 65.3 μW cm–2 at 200 and 1000 lx, respectively. Increasing the open-circuit voltage (Voc) of OPVs is a critical factor for achieving higher indoor photovoltaic performance. Toward real applications, this small-molecule OPV system is adopted to fabricate six series-connected modules with an active area of ∼10 cm2 that are capable of generating a high output power surpassing 100 μW and a high Voc of over 4.2 V even under dimly lit indoor conditions of 200 lx. These results indicate that OPVs are promising as indoor electric power sources for self-sustainable electronic devices.

10.1021/acsami.9b00018

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Citations (80)

Oligothiophene–Indandione-Linked Narrow-Band Gap Molecules: Impact of π-Conjugated Chain Length on Photovoltaic Performance

ACS Applied Materials & Interfaces (2018)

Hideaki Komiyama Takahiro To Seiichi Furukawa Yu Hidaka Woong Shin

Solution-processed organic solar cells (OSCs) based on narrow-band gap small molecules hold great promise as next-generation energy-converting devices. In this paper, we focus on a family of A-π-D-π-A-type small molecules, namely, BDT- nT-ID ( n = 1-4) oligomers, consisting of benzo[1,2- b:4,5- b']dithiophene (BDT) as the central electron-donating (D) core, 1,3-indandione (ID) as the terminal electron-accepting (A) units, and two regioregular oligo(3-hexylthiophene)s ( nT) with different numbers of thiophene rings as the π-bridging units, and elucidate their structure-property-function relationships. The effects of the length of the π-bridging nT units on the optical absorption, thermal behavior, morphology, hole mobility, and OSC performance were systematically investigated. All oligomers exhibited broad and intense visible photoabsorption in the 400-700 nm range. The photovoltaic performances of bulk heterojunction OSCs based on BDT- nT-IDs as donors and a fullerene derivative as an acceptor were studied. Among these oligomers, BDT-2T-ID, incorporating bithiophene as the π-bridging units, showed better photovoltaic performance with a maximum power conversion efficiency as high as 6.9% under AM 1.5G illumination without using solvent additives or postdeposition treatments. These favorable properties originated from the well-developed interpenetrating network morphology of BDT-2T-ID, with larger domain sizes in the photoactive layer. Even though all oligomers have the same A-D-A main backbone, structural modulation of the π-bridging nT length was found to impact their self-organization and nanostructure formation in the solid state, as well as the corresponding OSC device performance.

Acceptor

Photoactive layer

10.1021/acsami.8b01233

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Citations (23)

Internal microstructure and formation mechanism of surface protrusions in Pb-Ti-Nb-O thin films prepared by MOCVD

Advanced Materials (2001)

X. D. Liu Hiroshi Funakubo Satoshi Noda Hideaki Komiyama

Pb-Ti-Nb-O ferroelectric thin films with various Nb additions are grown on a Pt/Ti/SiO 2 /Si substrate at 400 °C by metal-organic (MO) CVD. A high density of dome-like surface protrusions is observed by scanning electron microscopy (SEM) in all the as-prepared films. Both the shape and the size of the surface defects are found to be Nb-content-dependent. The internal microstructure of the protrusions is further characterized by cross-section transmission electron microscopy (XTEM). The origins of these surface defects are discussed, based on the substrate hillock as well as the crystallization behavior of the film forming precursors during MOCVD. The development of the observed surface defects is modeled using a two-dimensional vector analysis.

Hillock

Source

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Amphiphilic liquid‐crystalline 4‐miktoarm star copolymers with a siloxane junction leading to cylindrically nanostructured templates for a siloxane‐based nanodot array

Journal of Polymer Science Part A Polymer Chemistry (2015)

Md. Asadul Hoque Hideaki Komiyama Hiroki Nishiyama Keiji Nagai Takehiro Kawauchi

ABSTRACT Well‐defined A 3 B‐, A 2 B 2 ‐, and AB 3 ‐type 4‐miktoarm star copolymers ( M n = 10,500–16,200, M w / M n = 1.16–1.18) consisting of poly(ethylene oxide) (PEO) and polymethacrylate bearing an azobenzene mesogen (PMA(Az)) as the arms and cyclotetrasiloxane as the core unit were synthesized using a combined route composed of a thiol‐ene click reaction and atom transfer radical polymerization. Microphase‐separated structures of the star copolymers in thin films with a thickness of approximately 100 nm were investigated by GISAXS and TEM. The A 3 B‐type star ‐(PEO) 3 [PMA(Az)] 1 copolymer formed a more highly ordered PEO cylinder array with perpendicular alignment in the PMA(Az) matrix than that of the corresponding linear‐type block copolymer. The center‐to‐center distance of the PEO cylinders and the cylinder diameter were 13 and 4 nm, respectively. The highly ordered star ‐(PEO) 3 [PMA(Az)] 1 thin film was directly transferred to a siloxane‐based nanodot array by oxygen reactive ion etching. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54 , 1175–1188

Siloxane

Atom-transfer radical-polymerization

Silsesquioxane

10.1002/pola.27960

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Citations (7)

Enormously Wide Range Cylinder Phase of Liquid Crystalline PEO-b-PMA(Az) Block Copolymer

Macromolecules (2014)

Hideaki Komiyama Ryohei Sakai Shingo Hadano Sadayuki Asaoka Kaori Kamata

A series of amphiphilic liquid crystalline diblock copolymers, PEOm-b-PMA(Az)n, consisting of hydrophilic poly(ethylene oxide) and hydrophobic poly(methacrylate) moieties with side chains containing liquid crystalline (LC) azobenzene moieties, produced highly ordered microphase-separated films with PEO cylinders aligned perpendicular to the smectic LC layer of azobenzene in the PMA(Az) matrix. In this paper, morphological phase diagrams of PEOm-b-PMA(Az)n diblock copolymers above and below the isotropic transition temperature of LC azobenzene (Tiso) are presented. The diagrams are based on small-angle X-ray scattering (SAXS) measurements of approximately 70 kinds of polymers with varying degrees of polymerization in each block. An asymmetric phase diagram described against the volume fraction of PEO (fPEO) was obtained at temperatures above and below Tiso. The lamellar phase appears in the fPEO window 0.52 ≤ fPEO ≤ 0.78 above and below Tiso. Besides, the wide window, 0.087 ≤ fPEO < 0.52, allows the PEO cylinder phase to form below Tiso. In particular, the PEO sphere phase, observed above Tiso, was completely eliminated through an order–order transition (OOT) to the PEO cylinder phase in the window 0.087 ≤ fPEO ≤ 0.23. Such a large expansion in the PEO-cylinder-phase window could be attributed to the main chain of LC PMA(Az) being shorter than that of the flexible PEO chain, and LC azobenzene forming a smectic layer in the microphase separated system.

Azobenzene

Small-angle X-ray scattering

Side chain

10.1021/ma402356z

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Citations (50)

Polypyrrole Nanowire Array with High Aspect Ratio Fabricated by Block-Copolymer-Templated Electropolymerization

MRS Proceedings (2011)

Hideaki Komiyama Tomokazu Iyoda Kaori Kamata

Polypyrrole

10.1557/opl.2011.507

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Citations (2)

Transition-metal-free controlled polymerization for poly(p-aryleneethynylene)s

Chemical Science (2014)

Takanobu Sanji Asahi Motoshige Hideaki Komiyama Junko Kakinuma Rie Ushikubo

A transition-metal-free controlled polymerization for the attainment of poly(p-aryleneethynylene)s is developed. The polymerization of 1-pentafluorophenyl-4-[(trimethylsilyl)ethynyl]benzene with a catalytic amount of fluoride anions proceeds in a chain-growth-like manner to afford polymers with controlled molecular weights and low polydispersity indexes. The mechanism involves a pentacoordinated fluorosilicate as a key intermediate. The anionic "living" nature of this process is applied to block copolymerization and also surface-terminated polymerization.

10.1039/c4sc02872d

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Citations (20)