岡山大学保健環境センター公開講演会（2007年）の報告 透過型電子顕微鏡を用いた新規ナノ炭素材料の観察

本稿は平成19年6月7日に行われた岡山大学保健環境センター公開講演会(岡山大学保健環境センター主催)での講演「“ナノ”インパクト，ナノ材料の拓く未来と環境リスク評価」の内容を岡山大学保健環境センター (講演時，現在は岡山大学大学院環境学研究科) 高口 豊がまとめたものである

Effect of Fullerene Encapsulation on Radial Vibrational Breathing-Mode Frequencies of Single-Wall Carbon Nanotubes

We investigate the effects of C60 fullerene encapsulation on the radial breathing mode (RBM) of semiconducting single-wall carbon nanotubes (SWCNTs) under tunable laser excitations. The changes in the RBM frequencies after C60 insertions show characteristic behavior; higher frequency shifts are observed in the case of smaller diameter tubes (dt~1.32 nm). The observed frequency shifts are satisfactorily explained by the diameter-dependent interaction between the encapsulated C60 and the host SWCNTs

Electronically modified single wall carbon nanohorns with iodine adsorption

Tailoring electronic properties of single wall carbon nanohorn (SWCNH) is expected to develop the application potential in various fields. SWCNH is efficiently modified with iodine molecules by liquid phase adsorption. The adsorption isotherm of iodine on SWCNH was Langmuirian with the saturated adsorption amount of 185 +/- 10 mg g (1) (coverage 0.18), indicating a specific interaction between SWCNH and iodine. The DC electrical conductivity of SWCNH film prepared by dip-coating method increased with the iodine adsorption amount almost by a factor 10.ArticleCHEMICAL PHYSICS LETTERS. 501(4-6):485-490 (2011)journal articl

Multiwalled carbon nanotubes grown in hydrogen atmosphere : An x-ray diffraction study

X-ray diffraction study of multiwalled carbon nanotube (MWNT) grown by arc discharge in hydrogen atmosphere is presented. It is found that the thermal-expansion coefficient along the radial direction of MWNT is widely distributed in a range from 1.6×10-5 K-1 to 2.6×10-5 K-1, indicating the existence of both of Russian doll MWNT and highly defective MWNT. Russian doll MWNT is suggested to have the outer diameter less than ∼100  Å . Thicker MWNT's are typically highly defective, and may have the jelly roll (scroll) or defective polygonal structure consisting of flat graphite domains

Radiolabeling, whole-body single photon emission computed tomography/computed tomography imaging, and pharmacokinetics of carbon nanohorns in mice.

In this work, we report that the biodistribution and excretion of carbon nanohorns (CNHs) in mice are dependent on their size and functionalization. Small-sized CNHs (30-50 nm; S-CNHs) and large-sized CNHs (80-100 nm; L-CNHs) were chemically functionalized and radiolabeled with [(111)In]-diethylenetriaminepentaacetic acid and intravenously injected into mice. Their tissue distribution profiles at different time points were determined by single photon emission computed tomography/computed tomography. The results showed that the S-CNHs circulated longer in blood, while the L-CNHs accumulated faster in major organs like the liver and spleen. Small amounts of S-CNHs- and L-CNHs were excreted in urine within the first few hours postinjection, followed by excretion of smaller quantities within the next 48 hours in both urine and feces. The kinetics of excretion for S-CNHs were more rapid than for L-CNHs. Both S-CNH and L-CNH material accumulated mainly in the liver and spleen; however, S-CNH accumulation in the spleen was more prominent than in the liver.journal article20162016 07 22importe

30 inch Roll-Based Production of High-Quality Graphene Films for Flexible Transparent Electrodes

We report that 30-inch scale multiple roll-to-roll transfer and wet chemical doping considerably enhance the electrical properties of the graphene films grown on roll-type Cu substrates by chemical vapor deposition. The resulting graphene films shows a sheet resistance as low as ~30 Ohm/sq at ~90 % transparency which is superior to commercial transparent electrodes such as indium tin oxides (ITO). The monolayer of graphene shows sheet resistances as low as ~125 Ohm/sq with 97.4% optical transmittance and half-integer quantum Hall effect, indicating the high-quality of these graphene films. As a practical application, we also fabricated a touch screen panel device based on the graphene transparent electrodes, showing extraordinary mechanical and electrical performances

Electronically modified single wall carbon nanohorns with iodine adsorption

Tailoring electronic properties of single wall carbon nanohorn (SWCNH) is expected to develop the application potential in various fields. SWCNH is efficiently modified with iodine molecules by liquid phase adsorption. The adsorption isotherm of iodine on SWCNH was Langmuirian with the saturated adsorption amount of 185 +/- 10 mg g (1) (coverage 0.18), indicating a specific interaction between SWCNH and iodine. The DC electrical conductivity of SWCNH film prepared by dip-coating method increased with the iodine adsorption amount almost by a factor 10.ArticleCHEMICAL PHYSICS LETTERS. 501(4-6):485-490 (2011)journal articl

Nucleation of WS2\bf WS_2 Fullerenes at Room Temperature

Inorganic nested fullerene-like particles of layered compound WS$_2$ were observed by high resolution transmission electron microscopy. It is shown, for the first time, that these structures can be nucleated inside the amorphous matrix at room temperature. At this condition the nucleation process may take 3-4 years