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Graphene-based hybrid (ZnP-azaBDP)-graphene was synthesized, comprehensively characterized and found to manage energy transfer processes, yielding upon illumination (ZnP-azaBDP˙−)-graphene˙+ charge-separated state.

Aims/Introduction This study examined the association between body mass index (BMI) and the risk of sarcopenia in Japanese type 2 diabetes patients. Materials and Methods Patients with type 2 diabetes who visited an outpatient clinic comprised the study’s participants. Sarcopenia was defined using the definition of the Asian Working Group for Sarcopenia 2014. The area under the curve was examined for the presence of sarcopenia based on the receiver operating characteristic curve of BMI. Results Among 1,137 patients, 210 were diagnosed with low grip strength, 78 with slow gait speed, 444 with low muscle mass and 142 with sarcopenia. The optimal cut‐off point of BMI level for risk of sarcopenia was 24.4 kg/m2 (area under the curve 0.729, 95% confidence interval 0.688–0.770, sensitivity 0.587, specificity 0.789). Furthermore, the receiver operating characteristic curve of BMI for sarcopenia did not significantly differ (P = 0.09) from that of gait speed, an established marker of sarcopenia. In both the male and female groups, there was no difference between the receiver operating characteristic curves of BMI and gait speed for sarcopenia. (P = 0.23 and P = 0.40, respectively). Conclusions These results suggest that a BMI, In this cross‐sectional study, the optimal cut‐off point of body mass index level for risk of sarcopenia was approximately 24 kg/m2, and the receiver operating characteristic curve of body mass index for sarcopenia did not significantly differ from that of gait speed, an established marker of sarcopenia in Japanese type 2 diabetes patients.

The photoluminescence of lanthanide ions inside fullerenes is usually very weak due to the quenching effect of the fullerene cage. In the case of Er@C82, the near-infrared emission from the Er3+ io...

Encapsulation by hexagonal boron nitride (hBN) has been widely used to address intrinsic properties of two-dimensional (2D) materials. The hBN encapsulation, however, can alter properties of 2D materials through interlayer orbital hybridization. In this paper, we present measurements of temperature dependence of photoluminescence intensity from monolayer MoS2 encapsulated by hBN flakes. The obtained temperature dependence shows an opposite trend to that of previously observed in a monolayer MoS2 on a SiO2 substrate. This is caused by the existence of stable momentum-forbidden dark excitons in the hBN-encapsulated MoS2. Ab-initio band-structure calculations have shown that orbital hybridization between MoS2 and hBN leads to upward shift of Γ-valley of MoS2, which results in lowering of energy of the momentum-forbidden dark excitons. This work shows an important implication that the hBN-encapsulated structures used to address intrinsic properties of two-dimensional crystals can alter basic properties of encapsulated materials.

Many different phase structures have been discovered for silver iodides. The β and γ phases were found to be the most common ones at ambient conditions, while the rock-salt phase was found to be stable under pressures between 400 MPa and 11.3 GPa. Recently, the α phase was demonstrated to be stable under ambient conditions when the particle sizes were reduced to below 10 nm. However, no other phase has been reported to be stable for silver iodides under ambient conditions. Rock-salt and helix structures have been found to be stable under ambient conditions in this study. The structures have been characterized by elemental mapping, Raman scattering, and high-resolution transmission electron microscopy. The stabilities of these structures were also confirmed by molecular dynamics and density functional theory.

The successful isolation of single layers from two-dimensional (2D) van der Waals (vdW)-layered materials has opened new frontiers in condensed matter physics and materials science. Their discovery and unique properties laid the foundation for exploring 1D counterparts. However, the isolation of 1D vdW-wired materials has thus far remained a challenge, and effective techniques are demanded. Here we report the facile synthesis of isolated transition-metal monochalcogenide MoTe nanowires by using carbon nanotubes (CNTs) as molds. Individual nanowires are perfectly separated by CNTs with a minimal interaction, enabling detailed characterization of the single wires. Transmission electron microscopy revealed unusual torsional motion of MoTe nanowires inside CNTs. Confinement of 1D vdW-wired materials to the nanotest tubes might open up possibilities for exploring unprecedented properties of the nanowires and their potential applications such as electromechanical switching devices.

Atomically thin one-dimensional (1D) van der Waals wires of transition metal monochalocogenides (TMMs) have been anticipated as promising building blocks for integrated nanoelectronics. While reliable production of TMM nanowires has eluded scientists over the past few decades, we finally demonstrated a bottom-up fabrication of MoTe nanowires inside carbon nanotubes (CNTs). Still, the current synthesis method is based on vacuum annealing of reactive MoTe2, and limits access to a variety of TMMs. Here we report an expanded framework for high-yield synthesis of the 1D tellurides including WTe, an previously unknown family of TMMs. Experimental and theoretical analyses revealed that the choice of suitable metal oxides as a precursor provides a useful yield for their characterization. These TMM nanowires exhibit a significant optical absorption in the visible-light region. More important, electronic properties of CNTs can be tuned by encapsulating different TMM nanowires.

Aim This study examined the association among sarcopenia and various surrogate markers of atherosclerosis in Japanese patients with type 2 diabetes (T2D). Methods Patients with T2D who visited the outpatient clinic comprised the study's participants. Handgrip strength (Grip), usual gait speed (GS) and skeletal muscle index, in addition to glycated hemoglobin, ankle-brachial index (ABI) and intima-media thickening (IMT), were measured in 1030 patients for the diagnosis of sarcopenia. From these results were obtained three categorical data (without sarcopenia [NS], sarcopenia with two factors [Sw2], sarcopenia with three factors [Sw3]), and continuous data for atherosclerosis. Results Glycated hemoglobin was significantly high among patients in the Sw3 category, as well as among all patients with sarcopenia, compared with those in the NS group, after adjustment was made for age, gender, duration of diabetes, and medications for hypertension and dyslipidemia. ABI was significantly low among the Sw2 and Sw3 patients, as well as among all patients with sarcopenia, but mean and maximum IMT were not when compared with the NS category of patients after the adjustment described above. However, skeletal muscle index, Grip and GS were positively associated with ABI after the adjustment. Grip and GS were negatively associated with maximum IMT after the adjustment. Conclusions These results imply that measurements to diagnose sarcopenia could play an important role for early detection of preclinical atherosclerosis, specifically peripheral artery disease, among Japanese patients with T2D. Geriatr Gerontol Int ••; ••: ••-•• Geriatr Gerontol Int 2020; ••: ••-••.

Recent studies have revealed that van der Waals (vdW) heteroepitaxial growth of 2D materials on crystalline substrates, such as hexagonal boron nitride (hBN), leads to the formation of self-aligned grains, which results in defect-free stitching between the grains. However, how the weak vdW interaction causes a strong limitation on the crystal orientation of grains is still not understood yet. In this work, we have focused on investigating the microscopic mechanism of the self-alignment of MoS2 grains in vdW epitaxial growth on hBN. Using the density functional theory and the Lennard-Jones potential, we found that the interlayer energy between MoS2 and hBN strongly depends on the size and crystal orientation of MoS2. We also found that, when the size of MoS2 is several tens of nanometers, the rotational energy barrier can exceed ∼1 eV, which should suppress rotation to align the crystal orientation of MoS2 even at the growth temperature.

DySc2N@C80 is an endohedral metallofullerene showing single-molecule magnet (SMM) behavior. In this work, we encapsulated DySc2N@C80-SMMs into the internal one-dimensional nanospace of single-walled carbon nanotubes (SWCNTs). Using transmission electron microscopy, “peapod” structures were clearly observed. From magnetic field dependent measurements, DySc2N@C80 showed stepwise hysteresis characteristic of SMMs even inside the SWCNTs, and the coercivity increased from 0.5 to 4 kOe. In addition, it showed slow relaxation of the magnetization without an applied external magnetic field. This system is the first example where SMMs have been encapsulated in SWCNTs, and this system could be used in future molecular-spintronics devices.

We developed the synthesis of one-dimensional polythiophenes inside single-wall carbon nanotubes (SWCNTs). Direct vapor-phase reaction with dibromobithiophenes provided long-conjugated polythiophen...

We investigate the photophysical properties of polymer-encapsulating single-walled carbon nanotubes (SWNTs) using absorption spectroscopy, photoconductivity spectroscopy, and femtosecond pump–probe spectroscopy. In a polythiophene (PT)-encapsulating SWNT film, one or two PT layers are encapsulated within SWNTs, depending on the tube diameter. For single encapsulated PT layers, the photoconductivity action spectrum shows a large photocurrent signal corresponding to absorption bands associated with PT exciton and continuum states, indicating charge transfer between the PT and the small-diameter SWNT. Pump–probe measurements show that electron transfer to the SWNT occurs in 0.53 ps and electrons then recombine with holes remaining in the PT in 11 ps. In a coronene-polymer-encapsulating SWNT film, weak absorption bands at 1.7 and 3.4 eV are observed in addition to the SWNT spectrum. Band calculations allow these to be assigned to optical transitions between the electronic states originating from the coronene ...

Extending π-electron systems are among the most important topics in physics, chemistry and materials science because they can result in functional materials with applications in electronics and optics. Conventional processes for π-electron extension, however, can generate products exhibiting chemical instability, poor solubility or disordered structures. Herein, we report a novel strategy for the synthesis of π-conjugated polymers within the interiors of carbon nanotubes (CNTs). In this process, thiophene-based oligomers are encapsulated within CNTs as precursors and are subsequently polymerized by thermal annealing. This polymerization increases the effective conjugation length of the thiophenes, as confirmed by transmission electron microscopy and absorption peak red shifts. This work also demonstrates that these polythiophenes can serve as effective markers for individual CNTs during Raman imaging with single-wavelength laser excitation due to their strong absorbance. In addition, stable carrier injection into the encapsulated polythiophenes is found to be possible via electrochemical doping. Such doping has the potential to produce π-electron-based one-dimensional conductive wires and highly stable electrochromic devices.

A van der Waals (vdW) heterostructure composed of multivalley systems can show excitonic optical responses from interlayer excitons that originate from several valleys in the electronic structure. In this work, we studied photoluminescence (PL) from a vdW heterostructure, WS2/MoS2, deposited on hexagonal boron nitride (hBN) flakes. PL spectra from the fabricated heterostructures observed at room temperature show PL peaks at 1.3–1.7 eV, which are absent in the PL spectra of WS2 or MoS2 monolayers alone. The low-energy PL peaks we observed can be decomposed into three distinct peaks. Through detailed PL measurements and theoretical analysis, including PL imaging, time-resolved PL measurements, and calculation of dielectric function e(ω) by solving the Bethe–Salpeter equation with G0W0, we concluded that the three PL peaks originate from direct K–K interlayer excitons, indirect Q−Γ interlayer excitons, and indirect K−Γ interlayer excitons.

1,6-Bis(hydroxymethyl)diamantane spontaneously aligns inside double-walled carbon nanotubes. The encapsulated molecules form a one-dimensional network within the double-walled carbon nanotubes through hydrogen bonding that leads to a highly dense filling as compared to unfunctionalized diamantane. Improving the encapsulation yields of precursors via functionalization is crucial to prepare novel one-dimensional materials.

We investigated the energetics and electronic structure of B3 N3 -doped graphene employing density functional theory calculations with the generalized gradient approximation. Our calculations reveal that all of the B3 N3 -doped graphene structures are semiconducting, irrespective of the periodicity of the B3 N3 embedded into the graphene network. This is in contrast to graphene nanomeshes, which are either semiconductors or metals depending on the mesh arrangement. In B3 N3 -doped graphene, the effective masses for both electrons and holes are small. The band gap in the B3 N3 -doped graphene networks and the total energy of the B3 N3 -doped graphene are inversely proportional to the B3 N3 spacing. Furthermore, both properties depend on whether or not the graphene region possesses a Clar structure. In particular, the sheets with a Clar structure exhibit a wider band gap and a slightly lower total energy than those without a Clar structure.

Fullerene dyads bridged with perfluorinated linking groups have been synthesized through a modified arc‐discharge procedure. The addition of Teflon inside an arc‐discharge reactor leads to the formation of dyads, consisting of two C60 fullerenes bridged by CF2 groups. The incorporation of bridging groups containing electronegative atoms lead to different energy levels and to new features in the photoluminescence spectrum. A suppression of the singlet oxygen photosensitization indicated that the radiative decay from singlet‐to‐singlet state is favoured against the intersystem crossing singlet‐to‐triplet transition.

Endohedral metallofullerene M@C66 (M = rare earth metal) has a unique structure that violates the well known "isolated pentagon rule" in fullerene science. Although the synthesis of M@C66 has been achieved by using the arc-discharge method, the solvent extraction and purification of M@C66 remain challenges because of its radical character and extremely high reactivity. In this paper, we theoretically demonstrate the possibility of capturing this missing metallofullerene by exohedral functionalization of the C66 cage. We have found stable trifluoromethylated derivatives of Y@C66 by density functional theory calculations. Mono- or multi-trifluoromethylation of Y@C66 results in a closed-shell electronic configuration and a large bandgap of the molecule. Thus Y@C66 could be stabilized greatly through trifluoromethylation. The trifluoromethyl group prefers to be attached to the fused pentagon region to release local steric strain. We also investigated the isomerization mechanism of Y@C66(CF3)3 and found that the attached trifluoromethyl group can migrate from a carbon atom to another one through a transition state.

Modulation of the local density of states of single-wall carbon nanotubes (SWCNTs) is induced by the encapsulation of europium nanowires (EuNWs). The observation of these modulated density of states using scanning tunneling microscopy/spectroscopy combined with density functional theory calculations is reported. The electronic modulation of SWCNTs by encapsulation of EuNWs is revealed as a Fermi level shift, band gap reduction, and the emergence of localized states in the gap. The present results show that the electronic interaction between EuNWs and SWCNTs is much stronger than that previously reported for nanomaterials encapsulated in SWCNTs.

Temperature dependent Raman spectra of a Dy@C82 thin film are investigated between 80 and 300 K. The first order temperature coefficient is evaluated for both Dy–C and C–C vibrational modes which reveals the presence of thermal and anharmonic contributions to the phonon hardening at low temperatures. The Dy–C mode broadens while decreasing the temperature revealing that the electron–phonon coupling is dominant over phonon–phonon coupling at low temperatures. In addition, laser-power dependent Raman spectra of Dy@C82 and Gd@C82 have been analyzed for estimating their first order power coefficients and the thermal conductivities.

Optical responses from two-dimensional semiconductors, such as monolayer transition metal dichalcogenides (TMDs), are dominated by excitonic effects due to strong Coulomb interaction between electrons and holes. Diffusion of excitons is, therefore, one of the most important processes to understand optical responses in 2D semiconductors. In this work, we have prepared a high-quality TMD, monolayer MoSe 2 encapsulated by hBN flakes (hBN/MoSe2/hBN), and investigated intrinsic exciton diffusion at various temperatures ranging from 10 ∼ 300 K. We found that Exciton mobility in hBN/MoSe 2 /hBN monotonically increases as temperature decreases, and mobility at 10 K reaches over 104 cm2V−1s−1.

We have investigated atomic and electronic structure of grain boundaries in monolayer MoS2, where relative angles between two different grains are 0 and 60 degree. The grain boundaries with specific relative angle have been formed with chemical vapor deposition (CVD) growth on graphite and hexagonal boron nitride flakes; van der Waals interlayer interaction between MoS2 and the flakes restricts the relative angle between two different grains of MoS2. Through scanning tunneling microscopy (STM) and spectroscopy measurements, we have found that the perfectly stitched structure between two different grains of MoS2 was realized in the case of the 0 degree grain boundary. We also found that even with the perfectly stitched structure, valence band maximum (VBM) and conduction band minimum (CBM) shows significant blue shift, which probably arise from lattice strain at the boundary.

The functionalization of MoS

The bottom-up preparation and in-situ functionalization of MoS2 with poly(methacrylic acid) (PMAA), was accomplished. For the realization of the PMAA-MoS2 hybrid material a facile yet fast protocol based on the thermal decomposition of ammonium tetrathiomolybdate, as source for Mo and S, under microwave irradiation and in the presence of PMAA was employed. The PMAA-MoS2 was characterized by complementary spectroscopic, thermal and electron microscopy imaging techniques. Moreover, meaningful information about the dispersibility, the nature of the colloidal dispersion and the solution properties of the hybrid material were acquired by dynamic light scattering assays.

Fluorescent carbon dots (CDs) were synthesized by following a hydrothermal route in which butane-1,4-diamine and maleic acid were employed in a Teflon autoclave reactor. The structure and morphology of the so-formed spherically shaped CDs were confirmed by a combination of spectroscopic and imaging techniques, such as NMR, ATR-IR, DLS, XRD, and HR-TEM. Additionally, it was found that raw CDs possess numerous −NH2 functionalities located in their external periphery, responsible for their enhanced aqueous solubility as well as the excellent dissolution CDs showed in polar protic solvents. Moreover, these −NH2 units were utilized for covalently associating CDs with oxidized multiwalled carbon nanotubes (MWCNTs) yielding robust CDs–MWCNTs hybrids. Based on photoluminescence spectroscopy, electronic communications between the individual components of CDs–MWCNTs were evidenced by the quantitative quenching of the emission of CDs in the presence of MWCNTs as well as the shortening of the photoluminescence lifeti...

By utilizing graphene-sandwiched structures recently developed in this laboratory, we are able to visualize small droplets of liquids in nanometer scale. We have found that small water droplets as small as several tens of nanometers sandwiched by two single-layer graphene are frequently observed by TEM. Due to the electron beam irradiation during the TEM observation, these sandwiched droplets are frequently moving from one place to another and are subjected to create small bubbles inside. The synthesis of a large area single-domain graphene of high-quality is essential to prepare the graphene sandwiched cell which safely encapsulates the droplets in nanometer size.

Conjugated polymers can selectively wrap around single-walled carbon nanotubes (SWNTs) with specific chiral angles and diameters. Such a hybrid material containing both SWNTs and polymers is attractive for applications such as organic photovoltaic devices and photosensors. In this study, we investigate excitation energy transfer (EET) in a paper form of semiconducting SWNTs wrapped by poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO) by means of photoluminescence (PL) excitation spectroscopy and time-resolved luminescence spectroscopy. Photoluminescence excitation maps and spectra show PL peaks when the 0–0 singlet transition of PFO is excited at 2.88 eV, as well as peaks corresponding to EET between semiconducting SWNTs wrapped by PFO. The PL decay time measured for a drop-cast PFO film is 82 ps, whereas the decay time due to PFO in the PFO-wrapped SWNT sample is as short as 0.38 ps. From these results, the EET rate between PFO and SWNTs is estimated to be 2.6 × 1012 s–1. Comparison of the highest occupied molec...

The simultaneous polymer functionalization and exfoliation of graphene sheets by using mild bath sonication and heat treatment at low temperature is described. In particular, free-radical polymerization of three different vinyl monomers takes place in the presence of graphite flakes. The polymerization procedure leads to the exfoliation of graphene sheets and at the same time the growing polymer chains are attached onto the graphene lattice, which gives solubility and stability to the final graphene-based hybrid material. The polymer-functionalized graphene sheets possess fewer defects as compared with previously reported polymer-functionalized graphene. The success of the covalent functionalization and exfoliation of graphene was confirmed by using a variety of complementary spectroscopic, thermal, and microscopy techniques, including Raman, IR and UV/Vis spectroscopy, thermogravimetric analysis, and transmission electron microscopy.

Endohedral metallofullerenes have been extensively studied since the first experimental observation of La@C60 in a laser-vaporized supersonic beam in 1985. However, most of these studies have focused on metallofullerenes larger than C60 such as Ln@C82 (Ln: lanthanide). There are few examples for isolation of small-cage (C60, C70, C72, and C74) lanthanide metallofullerenes because of their extremely high chemical reactivity. Recently, we developed an in situ trifluoromethylation method for the extraction and purification of these missing metallofullerenes [1−3]. Here we report the isolation and structure determination of trifluoromethylated gadolinium metallofullerenes (Gd@C60(CF3)3, Gd@C60(CF3)5, Gd@C70(CF3)3, Gd@C74(CF3), and Gd@C74(CF3)3). Gd-metallofullerenes are promising as magnetic resonance imaging (MRI) contrast agents. The fully enclosing carbon cage completely prevents leaching of the Gd atoms, resulting in lower toxicity than commercially available metal chelate reagents such as Gd-DTPA. Trifluoromethylated Gd-metallofullerenes were synthesized by the modified arc-discharge method. PTFE rods are placed near the discharge area as CF3 source. During arc discharge, PTFE was decomposed and evaporated to produce CF3 radicals. Gd-metallofullerenes and empty fullerenes were extracted from the raw soot with o-xylene. Rapid separation of Gd-metallofullerenes from empty fullerenes was carried out by the TiCl4 Lewis acid method. High-performance liquid chromatography (HPLC) purification was conducted for isolation of trifluoromethylated Gd-metallofullerenes. Single crystals of trifluoromethylated Gd-metallofullerenes were obtained from solution. The single-crystal X-ray diffraction data for structure determination were collected at SPring-8 large synchrotron radiation facility. Figures show the molecular structures of Gd@C74(CF3) (I), Gd@C74(CF3) (II), and Gd@C74(CF3)3 derived from the X-ray crystal structure analysis. The closed-shell molecular structures are theoretically stable and have wide HOMO-LUMO energy gaps. [1] Z. Wang et al. Angew. Chem. Int. Ed. 55, 199 (2016). [2] A. Nakagawa et al. Nature. Commun. 9, 3073 (2018). [3] A. Nakagawa et al. R. Soc. Open Sci. 5, 181015 (2018). Figure 1

We show that blister-based-laser-induced forward transfer (BB-LIFT) can be used to cleanly desorb and transfer nano- and micro-scale particles between substrates without exposing the particles to the laser radiation or to any chemical treatment that could damage the intrinsic electronic and optical properties of the materials. The technique uses laser pulses to inducethe rapid formation of a blister on a thin metal layer deposited on glass via ablation at the metal/glass interface. Femtosecond laser pulses are advantageous for forming beams of molecules or small nanoparticles with well-defined velocity and narrow angular distributions. Both fs and ns laser pulses can be used to cleanly transfer larger nanoparticles including relatively fragile monolayer 2D transition metal dichalcogenide crystals and for direct transfer of nanoparticles from chemical vapour deposition (CVD) growth substrates, although the mechanisms for inducing blister formation are different.

Using density functional theory approaches, we follow the sequential addition of CF 3 functional groups to the surface of the metallic endofullerene species Gd@C 60 . The presence of gadolinium in the interior of the cage strongly influences the addition sequence. The calculations are able to successfully identify end points in the addition sequence at Gd@C 60 (CF 3 ) n , n = 3 and two isomers at n = 5, in predictive agreement with experiment. Inverting the algorithm to determine the most labile groups also identifies the correct positively charged Gd@ C 60 ( C F 3 ) 4 + isomer, as confirmed by experimental mass spectra. The importance of surface mobility, notably at later stage addition, is discussed.

A van der Waals (vdW) heterostructure composed of multivalley systems can show excitonic optical responses from interlayer excitons that originate from several valleys in the electronic structure. In this work, we studied photoluminescence (PL) from a vdW heterostructure, WS

Molecule encapsulation inside the single-walled carbon nanotube (SWCNT) core has been demonstrated to be a successful route for the modification of nanotube properties. SWCNT diameter-dependent filling results in band gap modification together with the enhancement of photoluminescence quantum yield. However, the interaction between the inner structure and the outer shell is complex. It depends on the orientation of the molecules inside, the geometry of the host nanotube and on several other mechanisms determining the resulting properties of the hybrid nanosystem. In this work we study the influence of encapsulated graphene nanoribbons on the optical properties of the host single-walled carbon nanotubes. The interplay of strain and dielectric screening caused by the internal environment of the nanotube affects its band gap. The photoluminescence of the filled nanotubes becomes enhanced when the graphene nanoribbons are polymerized inside the SWCNTs at low temperatures. We show a gradual photoluminescence quenching together with a selective signal enhancement for exact nanotube geometries, specifically (14,6) and (13,8) species. A precise adjustment of the optical properties and an enhancement of the photoluminescence quantum yield upon filling for nanotubes with specific diameters were assigned to optimal organization of the inner structures.

Fullerene dyads bridged with perfluorinated linking groups have been synthesized through a modified arc-discharge procedure. The addition of Teflon inside an arc-discharge reactor leads to the formation of dyads, consisting of two C