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Surface modification using zwitterionic 2-methacryloyloxyethylphosphorylcholine (MPC) polymers is one of the most reasonable ways to prepare medical devices that can suppress undesired biological reactions such as blood coagulation. Usable MPC polymers are hydrophilic and water soluble, and their surface modification strategy involves exploiting the copolymer structures by adding physical or chemical bonding moieties. In this study, we developed copolymers composed of MPC, hydrophobic anchoring moiety, and chemical cross-linking unit to clarify the role of hydrophobic interactions in achieving biocompatible and long-term stable coatings. The four kinds of MPC copolymers with cross-linking units, such as 3-methacryloxypropyl trimethoxysilane (MPTMSi), and four different hydrophobic anchoring moieties, such as 3-(methacryloyloxy)propyltris(trimethylsiloxy)silane (MPTSSi) named as PMMMSi, n -butyl methacrylate (BMA) as PMBSi, 2-ethylhexyl methacrylate (EHMA) as PMESi, and lauryl methacrylate as PMLSi, were synthesized and coated on polydimethylsiloxane, polypropylene (PP), and polymethyl pentene. These copolymers were uniformly coated on the substrate materials PP and poly(methyl pentene) (PMP), to achieve hydrophilic and electrically neutral coatings. The results of the antibiofouling test showed that PMBSi repelled the adsorption of fluorescence-labeled bovine serum albumin the most, whereas PMLSi repelled it the least. Notably, all four copolymers suppressed platelet adhesion similarly. The variations in protein adsorption quantities among the four copolymer coatings were attributed to their distinct swelling behaviors in aqueous environments. Further investigations, including 3D scanning force microscopy and neutron reflectivity measurements, revealed that the PMLSi coating exhibited a higher water intake under aqueous conditions in comparison to the other coatings. Consequently, all copolymer coatings effectively prevented the invasion of platelets but the proteins penetrated the PMLSi network. Subsequently, the dynamic stability required to induce shear stress was evaluated using a circulation system. The results demonstrated that the PMMMSi and PMLSi coatings on PMP and PP exhibited exceptional platelet repellency and maintained high stability during circulation. This study highlights the potential of hydrophobic moieties to improve hemocompatibility and stability, offering potential applications in medical devices.

Synthetic challenges toward anomalous structures and electronic states often involve handling problems such as insolubility in common organic solvents and oxidative degradation under aerobic conditions. We designed benzo-annulated aza[ n ]helicenes, which benefit from both the suppressed elevation of highest occupied molecular orbital (HOMO) energies and high solubility due to hydrogen bonding with solvent molecules to overcome these challenges. This strategy enabled the synthesis of six new aza[ n ]helicenes ( [ n ]AH s) of different lengths ( n = 9-19) from acyclic precursors via one-pot intramolecular oxidative fusion reactions. The structures of all of the synthesized aza[ n ]helicenes were determined by X-ray diffraction (XRD) analysis, and their electrochemical potentials were measured by cyclic voltammetry. Among the synthesized aza[ n ]helicenes, [17]AH and [19]AH are the first heterohelicenes with a triple-layered helix. The noncovalent interaction (NCI) plots confirm the existence of an effective π-π interaction between the layers. The absorption and fluorescence spectra red-shifted as the helical lengths increased, without any distinct saturation points. The optical resolutions of N -butylated [9]AH , [11]AH , [13]AH , and [15]AH were accomplished, and their circular dichroism (CD) and circularly polarized luminescence (CPL) were measured. Thus, the structural, (chir)optical, and electrochemical properties of the aza[ n ]helicenes were comprehensively analyzed.

We developed a substrate that enables highly sensitive and spatially uniform surface-enhanced Raman scattering (SERS). This substrate comprises densely packed gold nanoparticles (d-AuNPs)/titanium dioxide/Au film (d-ATA). The d-ATA substrate demonstrates modal ultrastrong coupling between localized surface plasmon resonances (LSPRs) of AuNPs and Fabry-Pérot nanocavities. d-ATA exhibits a significant enhancement of the near-field intensity, resulting in a 78-fold increase in the SERS signal for crystal violet (CV) compared to that of d-AuNP/TiO 2 substrates. Importantly, high sensitivity and a spatially uniform signal intensity can be obtained without precise control of the shape and arrangement of the nanoscale AuNPs, enabling quantitative SERS measurements. Additionally, SERS measurements of rhodamine 6G (R6G) on this substrate under ultralow adsorption conditions (0.6 R6G molecules/AuNP) show a spatial variation in the signal intensity within 3%. These findings suggest that the SERS signal under modal ultrastrong coupling originates from multiple plasmonic particles with quantum coherence.

Fullerenes are among the most commonly used electron-transporting materials (ETMs) in inverted perovskite solar cells (IPSCs). Although versatile functionalized fullerene derivatives have shown excellent performance in IPSCs, pristine [60]fullerene (C 60 ) is still the most widely used in devices mainly because of its uniform morphology by thermal deposition. However, thermally evaporable fullerene derivatives have not yet been achieved. Herein, we developed a series of evaporable fullerene derivatives, referred to as fullerene indanones (FIDOs), affording IPSCs with high power conversion efficiency (PCE) and long-term storage stability. The FIDOs were designed with a unique architecture in which the fullerene moiety and a benzene ring moiety are linked via a five-membered carbon ring in benzene ring plane. This molecular arrangement affords exceptional thermal stability, allowing the FIDOs to withstand harsh thermal deposition conditions. Moreover, by manipulating the steric bulk of the functional groups, we could control the state of the organic film from crystalline to amorphous. Subsequently, we used FIDOs as an electron transport layer (ETL) in IPSCs. Thanks to the suitable energy level and dual-passivation effect of FIDOs compared with a reference ETL using C 60 , the device using FIDOs achieved an open-circuit voltage of 1.16 V and a fill factor of 0.77. As a result, the PCE reached 22.11%, which is superior to 20.45% of the best-performing reference device. Most importantly, the FIDO-based IPSC devices exhibited exceptional stability in comparison to the reference device due to the stability of the amorphous ETL films.

Size segregation of nanoparticles with different sizes into highly ordered, unique nanostructures is important for their practical applications. Herein, we demonstrate spontaneous self-assembly of the binary mixtures of small and large gold nanoparticles (GNPs; 5/15, 5/20, or 10/20 in diameter) in the presence of a tetra(ethylene glycol)-terminated octafluoro-4,4'-biphenol ligand, namely, TeOFBL, resulting in a size-segregated assembly. The outer single layer of large GNPs forming a gold nanoparticle vesicle (GNV) encapsulated the inner vesicle-like assembly composed of small GNPs, which is referred to as bilayer-like GNV and similar to the molecular bilayer structure of a liposome. The size segregation was driven by the solvophobic feature of the TeOFBLs on the surface of GNPs. A time-course study indicated that size segregation occurred instantaneously during the mixing stage of the self-organization process. The size-segregated precursors quickly fused with each other through the inner-inner and outer-outer layer fashion to form the bilayer-like GNV. This study provides a new approach to creating biomimetic bilayer capsules with different physical properties for potential applications such as surface-enhanced Raman scattering and drug delivery.

Thearubigins (TRs) are chemically ill-defined black tea pigments composed of numerous catechin oxidation products. TRs contain oligomeric components; however, the oligomerization mechanisms are poorly understood. The comparison of the 13 C nuclear magnetic resonance (NMR) spectra of TRs with different molecular sizes suggested the participation of A-ring methine carbons in the oligomerization. Crushing fresh tea leaves with phloroglucinol, a mimic of the catechin A-rings, yielded the phloroglucinol adducts of the B-ring quinones of pyrogallol-type catechins and dehydrotheasinensins, indicating that intermolecular oxidative couplings between pyrogallol-type B-rings and A-rings are involved in the oligomerization. This is supported by the comparison of the 13 C NMR spectra of the oligomers generated from the dehydrotheasinensins and epicatechin. Furthermore, the presence of the quinones or related structures in the catechin oligomers is shown by condensation with 1,2-phenylenediamine. The pyrogallol-type catechins account for approximately 70% of tea catechins; therefore, the B-A ring couplings of the pyrogallol-type catechins are important in the catechin oligomerization involved in TR production.

Thermal transistors have potential as thermal management devices because they can electrically control the thermal conductivity (κ) of the active layer. Recently, we realized solid-state electrochemical thermal transistors by utilizing the electrochemical redox reaction of SrCoO y (2 ≤ y ≤ 3). However, the guiding principle to improve the on/off κ ratio has yet to be clarified because the κ modulation mechanism is unclear. This study systematically modulates κ of SrCo 1- x Fe x O y (0 ≤ x ≤ 1, 2 ≤ y ≤ 3) solid solutions used as the active layers in solid-state electrochemical thermal transistors. When y = 3, the lattice κ of SrCo 1- x Fe x O y is ∼2.8 W m -1 K -1 and insensitive to x . When x = 0 and y = 3, κ increases to ∼3.8 W m -1 K -1 due to the contribution of the electron κ. When y = 2, κ slightly depends on the ordered atomic arrangement. Materials that are high electrical conductors with highly ordered lattices when the transistor is on but are electrical insulators with disordered lattices when the transistor is off should be well-suited for the active layers of solid-state electrochemical thermal transistors.

Detection of metabolic activity enables us to reveal the inherent metabolic state of cells and elucidate mechanisms underlying cellular homeostasis and growth. However, a fluorescence approach for the study of metabolic pathways is still largely unexplored. Herein, we have developed a new chemical probe for the fluorescence-based detection of fatty acid β-oxidation (FAO), a key process in lipid catabolism, in cells and tissues. This probe serves as a substrate of FAO and forms a reactive quinone methide (QM) as a result of metabolic reactions. The liberated QM is covalently captured by intracellular proteins, and subsequent bio-orthogonal ligation with a fluorophore enables fluorescence analysis. This reaction-based sensing allowed us to detect FAO activity in cells at a desired emission wavelength using diverse analytical techniques including fluorescence imaging, in-gel fluorescence activity-based protein profiling (ABPP), and fluorescence-activated cell sorting (FACS). The probe was able to detect changes in FAO activity induced by chemical modulators in cultured cells. The probe was further employed for fluorescence imaging of FAO in mouse liver tissues and revealed the metabolic heterogeneity of FAO activity in hepatocytes by the combination of FACS and gene expression analysis, highlighting the utility of our probe as a chemical tool for fatty acid metabolism research.

A cathode material, graphene-like graphite, was developed for all-solid-state-type fluoride-ion shuttle batteries (FSBs). Fluoride ions were electrochemically introduced/extracted into/from it, and covalent C-F bonds were formed upon electrochemical oxidation. The introduction of fluoride ions into it occurred at a lower voltage than that into graphite. While the layered structure of graphite was completely destroyed during charging, that of graphene-like graphite was still maintained to some extent. The discharge voltage was higher than 1 V versus Pb/PbF 2 , which was higher than that of most of the previously reported cathode materials. The first discharge capacity (161 mAh g -1 ) was larger than that of graphite (140 mAh g -1 ), and the Coulombic efficiency and cyclability were much higher. This work demonstrates that graphene-like graphite prepared by thermal reduction of graphene oxide at 300 °C, GLG300, is a promising material for positive electrodes of FSBs.

A novel perovskite fluoride, Li x CoF 3 , which has an exceptionally low tolerance factor (0.81), has been synthesized via low-temperature lithium intercalation into a distorted ReO 3 -type fluoride CoF 3 using organolithium reagents. Interestingly, this reaction is completed within 15 min at room temperature. Synchrotron X-ray diffractometry and optical second harmonic generation at room temperature have revealed that this compound shows a high-temperature LiNbO 3 -type structure (space group: R 3̅ c ) involving Li-Co antisite defects and A -site splitting along the c direction. A -site splitting is consistent with the prediction based on hybrid Hartree-Fock density functional theory calculations. Co- L 2,3 edge X-ray absorption spectroscopy, as well as bond valence sum analysis, has verified the divalent oxidation state of Co ions in the lithiated phase, suggesting that its composition is close to LiCoF 3 ( x ≈ 1). This compound exhibits a paramagnetic-to-antiferromagnetic transition at 36 K on cooling, accompanied by weak ferromagnetic ordering. The synthetic route based on low-temperature lithiation of metal fluorides host paves the way for obtaining a new LiNbO 3 -type fluoride family.

A conjugated donor-acceptor antiaromatic porphyrin, composed of an antiaromatic thieno-fused porphyrin structure and a diketopyrrolopyrrole mioety, was synthesized and applied in a perovskite solar cell for the first time. Enhanced light absorption in the device by the antiaromatic porphyrin resulted in a significantly increased power conversion efficiency of 19.3%.

Underwater adhesive materials are in high demand in various fields, and fish species with sucker disks have attracted attention due to their superior performance and interesting structures. The clingfish, in particular, is widely known for using hierarchical sucker disk structures to demonstrate rapid and strong adhesion to rocky surfaces under strong currents. We examined the combination of nanofilaments and mucus in the clingfish sucker disk. Nanofilaments reinforce mucus adhesion force by reducing the compliance without affecting the contact area. We prepared structures from hard polymers and soft polydimethylsiloxane (PDMS) that mimicked clingfish sucker nanofilaments and mucus, with these biomimetic structures showing significant adhesion force underwater. Furthermore, the hardness and length of the nanofilaments and Young's modulus and thickness of the mucus-mimicking PDMS layer had critical effects on the adhesion force. According to the results, clingfish nanofilaments act as hard bracing for the soft mucus, and the structural combination of the conflicting characteristics of hardness and softness, thus achieved, is crucial for strong adhesion.

Efficient uptake of small to large guests, with a large difference in relative size, is quite rare for synthetic host compounds. Herein we designed and prepared a micellar capsule, composed of bent amphiphiles bearing two adamantyl groups, as a new host with a well-defined nanostructure. Unlike previous covalent, coordination, and hydrogen-bonding hosts, the adamantane-based capsule displays unusual uptake abilities toward spherical molecules with small (∼0.6 nm in diameter; e.g., adamantane) to medium size (∼1 nm; e.g., fullerene) as well as large size (∼3 nm; i.e., metal-organic polyhedra (MOP)), where the size differences are up to 5-fold, in water. Moreover, the resultant MOP-uptaking capsule incorporates medium-sized molecules (e.g., perylene and eosin Y) into the polyhedral cavity to generate ternary core-shell structures.

Vulcanized rubber is widely used in a wide range of applications because of its flexibility, durability, sealing properties, and high degree of friction. However, this high degree of friction can also become an issue, as it leads to the wearing and breakage of parts. In this report, we investigated the effects of the vulcanized rubber microstructures on friction force by using simple, anisotropic microstructures. The line and space master microstructures were prepared from a photoresist, and the structures were transferred to PDMS, PSt, and then Ni. After surface modification of the Ni microstructures by TEOS, the vulcanized rubber microstructures were fabricated by a simple hot press process with the TEOS-coated Ni microstructure molds. The structural parameters of the vulcanized rubber line and space microstructures were found to be successfully varied by elongation, and the structural deformations were also investigated by FEM simulations. Measurements of the frictional force of the vulcanized rubber microstructures revealed the friction coefficient was reduced by the surface microstructures and was affected by the directions of the contact because of the microstructure anisotropy. The reason for of these results can be explained by the changes in the contact area and hysteresis friction. These results suggest that the friction coefficients of vulcanized rubbers can be reduced by the simple surface microstructures that are applicable to a wide range of fields.

Wettability control of porous materials is significant in lateral flow immunoassay, microfluidic systems, microdroplet manipulation, and so on. In this report, formation of metal oxide layers on self-organized polymer honeycomb films to control surface wettability by simple sol-gel coating and UV-O 3 treatment was demonstrated. By the combination of bottom-up and top-down processes, silica thin layers can be formed by retaining their original three-dimensional honeycomb structures. Furthermore, photopatterning of metal oxides on honeycomb films can be achieved by UV irradiation through photomasks. Site-selective wettability control of honeycomb films was realized by patterning silica layers on the surface of the film.

Kinetic parameters for the [5,6]- to [6,6]-[Li + @PCBM]TFSI - transformation were determined experimentally, revealing a ca. 700-fold faster reaction rate at 423 K than empty PCBM and a 57.4 kJ mol -1 lower activation energy. The encapsulated Li + can be considered as solvation-free Li + , forming a 1:1 complex with the substrate.

The development of a strategy for the assembly of nanoscale building blocks, in particular, anisotropic nanoparticles, into desired structures is important for the construction of functional materials and devices. However, control over the orientation of rod-shaped nanoparticles on a substrate for integration into solid-state devices remains challenging. Here, we report a strategy for the fabrication of finely aligned gold nanorod (GNR) arrays using polymer (DNA) brushes as a nanoscale template. The gold nanorods modified with cationic surface ligands were electrostatically adsorbed onto the DNA brush substrates under various conditions. The orientational behavior of the GNRs was examined by spectral analyses and transmission electron microtomography (TEMT). As a result, we found several important factors, such as moderate interaction between GNRs and polymers and polymer densities on the substrate, related to the vertical alignment of GNRs on the substrates. We also developed a purification method to remove the undesired adsorption of GNRs onto the arrays. Finally, we have succeeded in the fabrication of extensive vertical GNR arrays of high quality via the easy bottom-up process.

The volatiles isolated by solvent extraction and solvent-assisted flavor evaporation (SAFE) from roasted barley tea, prepared from either hulled barley or naked barley, were subjected to a comparative aroma extract dilution analysis, which resulted in 27 odor-active compounds with flavor dilution factors (FD factors) of 64-1024. An additional 5 odorants were detected by static headspace analysis. Quantitation of these 32 compounds revealed 22 and 23 odorants in the naked barley tea and in the hulled barley tea, respectively, that exceeded their odor-threshold values. On the basis of these data, the aromas of both barley tea variants were successfully reconstituted with reference compounds. The calculation of odor-activity values (OAVs = concentration/odor-threshold value) and omission tests suggested 2-methoxyphenol (OAVs 69 and 160) and trans -isoeugenol (OAVs 1.4 and 31) as key compounds responsible for the stronger smoky note in the hulled barley tea. Further important odorants in the naked and hulled barley teas included 2-acetylpyrazine (OAVs 23 and 16), 2-acetyl-1-pyrroline (OAVs 19 and 16), and 3-methylbutanal (OAVs 12 and 15).

Deaminative functionalization of aliphatic primary amines has great synthetic utility. Herein, we describe a Ni-catalyzed reductive deaminative cross-electrophile coupling reaction between Katritzky salts and aromatic amides. This work provides examples of the synthesis of various ketones from alkylpyridinium salts, including both primary and secondary alkylamines. Given its mild reaction conditions and high functional group tolerance, this cross-coupling strategy is expected to be useful for late-stage functionalization of complex compounds.

A high-yielding protocol to construct six-membered carbon rings on fullerene is presented. This methodology with in situ fullerene-cation-mediated intramolecular cyclization provides high selectivity and efficient access to six-membered tetrahydronaphthaleno[60]fullerenes with a remarkable functional group tolerance and excellent yields. Furthermore, high solubilities of tetrahydronaphthaleno[60]fullerenes are reported.

High efficiency perovskite solar cells have underpinned the rapid growth of the field. However, their low device stability limits further advancement. Hygroscopic lithium bis(trifluoromethanesulfonyl)imide (Li + TFSI - ) and metal electrode are the main causes of the device instability. In this work, the redox reaction between lithium-ion endohedral fullerenes and 2,2',7,7'-tetrakis( N , N -di- p -methoxyphenylamine)-9,9'-spirobi-fluorene (spiro-MeOTAD) was controlled to optimize the amount of oxidized spiro-MeOTAD and antioxidizing neutral endohedral fullerenes. Application of this mixture to metal-free carbon nanotube (CNT)-laminated perovskite solar cells resulted in 17.2% efficiency with a stability time of more than 1100 h under severe conditions (temperature = 60 °C, humidity = 70%). Such high performance is attributed to the uninhibited charge flow, no metal-ion migration, and the enhanced antioxidizing activity of the devices.

Benzothieno[60]fullerenes were synthesized using fullerenyl cations as key intermediates. The reaction proceeded through a nucleophilic attack of the sulfur atom as a weak nucleophile to the fullerenyl cation electrophile. A monoarylated fullerene, (2-methylthiophenyl)hydro[60]fullerene, C 60 ArH (Ar = C 6 H 4 -SMe-2 and so on; four derivatives) was subjected to deprotonation with KO tBu to form a fullerenyl anion ArC 60 - , followed by oxidation using I 2 to generate a fullerenyl cation ArC 60 + , leading to intramolecular demethylative cyclization via fullerene cation-S interaction to the product. Electrochemical and computational studies revealed slightly narrower band gap of this compound than usual fullerene derivatives because of the relatively high-lying HOMO of the fused thieno moiety.

Single-walled carbon nanotubes (CNTs) has been considered as a promising material for a top electrode of perovskite solar cells owing to its hydrophobic nature, earth-abundance, and mechanical robustness. However, its poor conductivity, a shallow work function, and nonreflective nature have limited further enhancement in power conversion efficiency (PCE) of top CNT electrode-based perovskite solar cells. Here, we introduced a simple and scalable method to address these issues by utilizing an ex-situ vapor-assisted doping method. Trifluoromethanesulfonic acid (TFMS) vapor doping of the free-standing CNT sheet enabled tuning of conductivity and work function of the CNT electrode without damaging underneath layers. The sheet resistance of the CNT sheet was decreased by 21.3% with an increase in work function from 4.75 to 4.96 eV upon doping of TFMS. In addition, recently developed 2D perovskite-protected Cs-containing formamidium lead iodide (FACsPbI 3 ) technology was employed to maximize the absorption. Because of the lowered resistance, better energy alignment, and improved absorption, the CNT electrode-based PSCs produced a PCE of 17.6% with a J SC of 24.21 mA/cm 2 , V OC of 1.005 V, and FF of 0.72. Furthermore, the resulting TFMS-doped CNT-PSCs demonstrated higher thermal and operational stability than bare CNT and metal electrode-based devices.

Acetetracenylene-1,2-dione reacted with 3-ethylrhodanine in the presence of piperidine and Hantzsch ester via a Knoevenagel condensation-reduction sequence to give a tetracene-rhodanine adduct. This reduced Knoevenagel product exhibited magenta luminescence with a fluorescence quantum yield of φ = 0.34 and fluorescence lifetime of τ = 13.2 ns in toluene. Electrochemical studies and charge carrier transport measurements revealed ambipolar properties with hole and electron mobilities of 5.1 × 10 -7 and 1.6 × 10 -4 cm 2 /(V s), respectively.

Fullerenes have attracted considerable interest as an electron-transporting layer in perovskite solar cells. Fullerene-based perovskite solar cells produce no hysteresis and do not require high-temperature annealing. However, high power conversion efficiency has been only achieved when the fullerene layer is thermally evaporated, which is an expensive process. In this work, the limitations of a solution-processed fullerene layer have been identified as high crystallinity and the presence of remnant solvents, in contrast to a thermally deposited C 60 film, which has low crystallinity and no remaining solvents. As a solution to these problems, a mixed C 60 and C 70 solution-processed film, which exhibits low crystallinity, is proposed as an electron-transporting layer. The mixed-fullerene-based devices produce power conversion efficiencies as high as that of the thermally evaporated C 60 -based device (16.7%) owing to improved fill factor and open-circuit voltage. In addition, by vacuum-drying the mixed fullerene film, the power conversion efficiency of the solution-processed perovskite solar cells is further improved to 18.0%. This improvement originates from the enhanced transmittance and charge transport by removing the solvent effect. This simple and low-cost method can be easily used in any type of solar cells with fullerene as the electron-transporting layer.

The self-assembly of gold nanoparticles (GNPs) into a defined structure, particularly hollow capsule structures, provides great potential for applications in materials science and medicine. However, the complexity of the parameters for the preparation of those structures through self-assembly has limited access to critical mechanistic questions. With this in mind, we have studied GNP vesicle (GNV) formation through self-assembly by the surface modification of GNPs with low-molecular-weight ligands. Here, we successfully prepared GNVs composed of GNPs with a diameter of 30 nm by surface modification with carboxylic acid-terminated fluorinated oligo(ethylene glycol) ligands (CFLs). As the carboxylic acid has two states (protonated and deprotonated), the balance of the attraction and repulsion between GNPs covered with CFLs is tunable. Sodium carboxylate-terminated fluorinated oligo(ethylene glycol) ligands (SCFLs) provided smaller GNVs than did CFLs at 0.8 × 10 11 NPs/mL. Time-course study revealed that CFL-covered GNPs quickly form small aggregates and gradually grow to larger GNVs (ca. 200 nm), but no gradual growth was observed for SCFL-covered GNPs. This result indicated that the electrostatic repulsion inhibits fusion of the small GNVs. The size of the GNVs formed with the aid of CFLs was independent of the initial GNP concentration, but the extinction spectra were concentration-dependent. Electron microscopy imaging and simulations supported the defect formation in the assemblies. These results provided new insights into the vesicle formation mechanism.

C 2 v -Symmetric octaalkoxyfullerenes, C 60 (OR) 8 (R = CH 3 , C 2 H 5 , CH 2 CF 3 ), were synthesized by reacting octabromofullerene with the corresponding alcohols in the presence of AgBF 4 . The reactions occurred with no change in the addition pattern, and the compounds were unambiguously characterized by NMR spectroscopy and X-ray structure analysis. Electrochemical measurements revealed not only that these derivatives have stable redox properties but also that their LUMO levels can be tuned over a very wide range.

Aryl[60]fullerenyl cations (ArC 60 + ), which were generated by heating aryl[60]fullerenyl dimers (ArC 60 -C 60 Ar) to generate aryl[60]fullerenyl radicals (ArC 60 • ) followed by oxidation using Cu(II) salts (Cu(BF 4 ) 2 (aq)), were reacted with various functionalized aryl boronic acids to produce functionalized 1,4-diaryl[60]fullerenes. This protocol tolerated various functional groups, such as OH, NH 2 , COCH 3 , and Cl substituents, with yields reaching 93%. C 60 Ar 1 Ar 2 (Ar 2 = p-NH 2 C 6 H 4 ) was used as a dopant in a photoactive CH 3 NH 3 PbI 3 layer of a perovskite solar cell.

A diphenylanthracene dimethylamine derivative (9-{3,5-di( N, N-dimethylaminoethoxy)phenyl}-10-phenyl-anthracene, DPAMA) was synthesized by the Suzuki-Miyaura cross-coupling reaction. Its ammonium salt, 9-{3,5-di(trimethylammonium ethoxy)phenyl}-10-phenyl-anthracene dichloride (DPAMA-Cl), was also synthesized as a reference material. DPAMA was characterized by UV-vis and fluorescence spectroscopy, cyclic voltammetry, photoelectron yield spectroscopy, and X-ray photoelectron spectroscopy to evaluate the work function-modifying ability of DPAMA on indium tin oxide (ITO) and ZnO. The work functions of ITO and ZnO changed from 4.4 and 4.0 eV (pristine) to 3.8 and 3.9 eV, respectively. Using this surface modification effect of DPAMA, inverted organic light-emitting diodes were fabricated with device structures of ITO/DPAMA/Alq 3 /NPD/MoO 3 /Al (Alq 3 = tris(8-hydroxyquinolinato)aluminum; NPD = N, N'-di-[(1-naphthyl)- N, N'-diphenyl]-1,1'-(biphenyl)-4,4'-diamine) and ITO/ZnO/DPAMA/Alq 3 /NPD/MoO 3 /Al. Both devices showed good performance at the range of current density, 1-300 mA/cm 2 . The best inverted organic light-emitting diodes device showed luminance of 7720 cd/m 2 , current efficiency of 4.51 cd/A, and external quantum efficiency of 1.45%. Also, poly(3-hexylthiophene):mixed phenyl-C 61 and C 71 butyric acid methyl ester-based organic solar cells using DPAMA and DPAMA-Cl as electron-transporting materials showed power conversion efficiencies of 3.3 and 3.4%, respectively.

The reaction of [Li + @C 60 ]TFSI - (TFSI = bis(trifluoromethanesulfonyl)imide) with 9-diazofluorene directly produced a [6,6]-adduct of lithium-ion-containing fluoreno[60]fullerene, [6,6]-[Li + @C 60 (fluoreno)]TFSI - , which was crystallographically characterized. Cyclic voltammetry of the compound showed a reversible one-electron reduction wave at -0.51 V (vs Fc/Fc + ) and an irreversible reduction wave for the second electron. The latter was attributed to opening of the three-membered ring due to strong stabilization of the resulting sp 3 -carbanion by the encapsulated Li + and formation of a 14π-electron aromatic fluorenyl anion.

Transparent carbon electrodes, carbon nanotubes, and graphene were used as the bottom electrode in flexible inverted perovskite solar cells. Their photovoltaic performance and mechanical resilience were compared and analyzed using various techniques. Whereas a conventional inverted perovskite solar cells using indium tin oxide showed a power conversion efficiency of 17.8%, the carbon nanotube- and graphene-based cells showed efficiencies of 12.8% and 14.2%, respectively. An established MoO 3 doping was used for  carbon electrode-based devices. The difference in the photovoltaic performance between the carbon nanotube- and graphene-based cells was due to the difference in morphology and transmittance. Raman spectroscopy, and cyclic flexural testing revealed that the graphene-based cells were more susceptible to strain than the carbon nanotube-based cells, though the difference was marginal. Overall, despite higher performance, the transfer step for graphene has lower reproducibility. Thus, the development of better graphene transfer methods would help maximize the current capacity of graphene-based cells.

C 60 o-quinodimethane bisadducts [C 60 (QM) 2 ] are promising electron acceptors for bulk heterojuction (BHJ) organic solar cells (OSCs). However, previous production of C 60 (QM) 2 often resulted in excessive regioisomers, which were difficult to purify and might consequently obscure the structure-performance study of the organofullerene acceptors. Herein, the electrosynthesis of C 60 (QM) 2 is reported. The reaction exhibits a strong regiocontrol with generation of fewer regioisomers. Pure regioisomers of cis-2, trans-3, and e C 60 (QM) 2 are obtained, and the structures are solved with single-crystal X-ray diffraction. Interestingly, the cis-2 and trans-3 regioisomers exhibit better photovoltaic performance than the e regioisomer in the OSCs based on poly(3-hexylthiophene) (P3HT), which can be correlated with their structural difference.

Organic functionalization of lithium-ion-containing [60]fullerene, Li + @C 60 , was performed by using diphenyl(diazo)methane as a stable, readily available diazo compound to obtain lithium-ion-containing [5,6]- and [6,6]-diphenylmethano[60]fullerenes, Li + @C 61 Ph 2 . The bis(trifluoromethanesulfonyl)imide (TFSI) salts of [5,6]- and [6,6]-Li + @C 61 Ph 2 were successfully separated by using a cation exchange column with eluent containing LiTFSI. Improved separation protocol and high crystallinity of ionic components in less polar solvents enabled separate crystallization of each isomer. Both [5,6]-open and [6,6]-closed structures of Li + @C 61 Ph 2 were determined by synchrotron radiation X-ray crystallography. Elucidating the [5,6]-open methano[60]fullerene (fulleroid) structure will contribute to materials research on fulleroids.

Control over the orientation of metal nanorods is important for both fundamental and applied research. We show that gold nanorods (GNRs) can be aligned in a single direction by adsorbing positively charged GNRs onto a double-strand DNA-grafted substrate through electrostatic interaction. The ordered structure can be optimized by controlling the density of the positive charges on the surface of the GNRs. We found, in agreement with the results of theoretical simulation, that the resultant structure exhibits plasmonic properties that are dependent on the GNR orientation relative to the direction of an oscillating electric field. Our approach provides new insights into the polymer-assisted self-assembly of rod-shaped nanoparticles utilizing electrostatic interactions., Competing Interests: The authors declare no competing financial interest.

In nature, there exist many functional water-controlling surfaces, such as the water-repellent surface of lotus leaves, the superhydrophobic water-adhesive surface of rose petals, the water-harvesting surface of a beetle's back, and the water-transporting surface of the legs of Ligia exotica. These natural surfaces suggest that surface chemistry and hierarchical structures are essential for controlling the water behavior. We have reported the preparation of superhydrophobic and antireflection silicon nanospike-array structures using self-organized honeycomb-patterned films as three-dimensional dry-etching masks. Moreover, the surface wettability of the silicon nanospike-array structures can be easily transformed from superhydrophobic to superhydrophilic by changes in the surface chemistry. In this report, we show the preparation of water-controlling surfaces, such as water-harvesting and water-transporting surfaces, by the wettability patterning of silicon nanostructured surfaces. We prepared honeycomb-patterned films for dry-etching masks made from polystyrene and an amphiphilic polymer by casting a chloroform solution. After the fixation of the top layer of the honeycomb-patterned films on a single-crystal silicon substrate, reactive ion etching was performed. The as-prepared silicon nanospike-array structure showed superhydrophobicity, and the water contact angles were over 170°. After UV-O 3 treatment with photomasks, only the UV-irradiated surfaces showed superhydrophilicity, suggesting that we can obtain superhydrophobic- and superhydrophilic-patterned surfaces for which the patterns are the same as those of the photomasks. On the basis of these wettability-patterned surfaces, we demonstrated water harvesting by superhydrophilic dot-patterned surfaces and water transportation against gravity by superhydrophilic triangular-patterned surfaces. In particular, we investigated uphill water transport through the motion of droplets on tilting slopes based on the equation of motion. These results suggested that we can obtain superior microfluidic devices suitable for various applications through the use of optional wettability patterns.

The synthesis, crystal structures, photoluminescence, and magnetic properties of the melilite-type oxysulfide Sr 2 MnGe 2 S 6 O were investigated. This compound crystallizes in the melilite structure with space group P4̅2 1 m, in which two kinds of anions, S 2- and O 2- , occupy different crystallographic sites in an ordered manner. The temperature dependence of the magnetic susceptibility of Sr 2 MnGe 2 S 6 O shows a broad peak due to a two-dimensional magnetic interaction between Mn ions in the ab plane. The specific heat data show that this compound has an antiferromagnetic transition temperature (T N = 15.5 K) that is much higher than that of the oxide analogue Sr 2 MnGe 2 O 7 (T N = 4.4 K). DFT calculations showed that the magnetic interaction is enhanced by covalency in the Mn-S bonding.

Gold nanoparticles (GNPs) show promise as both drug and imaging carriers with applications in both diagnosis and therapy. For the safe and effective use of such gold nanomaterials in the biomedical field, it is crucial to understand how the size and shape of the nanomaterials affect their biological features, such as in vitro cellular uptake speed and accumulation as well as cytotoxicity. Herein, we focus on triangular gold nanoparticles (TNPs) of four different sizes (side length 46, 55, 72, and 94 nm; thickness 30 nm) and compare the cellular internalization efficiency with those of spherical nanoparticles (SNPs) of various diameters (22, 39, and 66 nm). Both surfaces were coated with anionic thiol ligands. Inductively coupled plasma-emission spectrometry (ICP-ES) data demonstrated that TNPs with longer sides showed higher levels of uptake into RAW264.7 and HeLa cells. On the other hand, in the case of SNPs, those with smaller diameters showed higher levels of uptake in both cells. Our results support the notion of a reverse size dependence of TNPs and SNPs in terms of cellular uptake. For HeLa cells, in particular, 20-fold more efficient internalization was observed for TNPs with longer sides (72 nm side length) compared to SNPs (66 nm) with a similar surface area. These results highlight the importance of the shape of nanomaterials on their interactions with cells and provide a useful guideline for the use of TNPs.

The extraordinary optical properties of coupled plasmonic nanostructures make these materials potentially useful in many applications; thus, they have received enormous attention in basic and applied research. Coupled plasmon modes have been characterized predominantly using far-field spectroscopy. In near-field spectroscopy, the spectral response of local field enhancement in coupled plasmonic nanostructures remains largely unexplored, especially experimentally. Here, we investigate the coupled gold dolmen nanostructures in the near field using photoemission electron microscopy, with wavelength-tunable femtosecond laser pulses as an excitation source. The spatial evolution of near-field mapping of an individual dolmen structure with the excitation wavelength was successfully obtained. In the near field, we spatially resolved an anti-bonding mode and a bonding mode as the result of plasmon hybridization. Additionally, the quadrupole plasmon mode that could be involved in the formation of a Fano resonance was also revealed by spatially resolved near-field spectra, but it only contributed little to the total near-field enhancement. On the basis of these findings, we obtained a better understanding of the near-field properties of coupled plasmonic nanostructures, where the plasmon hybridization and the plasmonic Fano resonance were mixed.

In this work, by casting water-soluble ammonium anthracene on metal oxides, the organic surface modifier re-engineered the interface of the metal oxide to improve charge transport. The energy level of ammonium anthracene increased the work function of indium tin oxide (ITO), functioning as a hole-blocker (electron-transporter). Solar cells in which ITO was treated by the ammonium anthracene produced an average power conversion efficiency (PCE) of 5.8% without ZnO, the electron-transporting layer. When the ammonium anthracene was applied to ZnO, an average PCE of 8.1% was achieved, which is higher than the average PCE of 7.5% for nontreated ZnO-based devices.

Size-controlled metal nanoparticles (NPs) were spontaneously formed when the amphiphilic diblock copolymers consisting of poly(vinyl catechol) and polystyrene (PVCa-b-PSt) were used as reductants and templates for NPs. In the present study, the proton conductivity of well-aligned lamellae structured PVCa-b-PSt films with Ag NPs was evaluated. We found that the proton conductivity of PVCa-b-PSt film was increased 10-fold by the addition of Ag NPs into the proton conduction channels filled with catechol moieties. In addition, the effect of humidity and the origin of proton conductivity enhancement was investigated.

Dipole and quadrupole modes are the two lowest orders of localized surface plasmon resonance (LSPR) eigenmodes in metallic nanoparticles. Of these two modes, the quadrupole mode is forbidden for symmetric metallic nanoparticles excited by linearly polarized light at normal incidence. Here, we demonstrate excitation of the quadrupole mode in symmetrical gold (Au) nanoblocks shined with s-polarized light at oblique incidence. In particular, we probe the near-field LSPR in Au nanoblocks using photoemission electron microscopy (PEEM) and find that at oblique incidence, the dipole and quadrupole modes can be selectively excited, in terms of near-field enhancement, by manipulating the light polarization state. More importantly, by time-resolved PEEM measurements, we experimentally demonstrate that the quadrupole mode in symmetrical Au nanoblocks has longer dephasing time than that of the dipole mode.

We demonstrate that binary mixtures of small and large gold nanoparticles (GNPs) (5/15, 5/30, 10/30, and 15/30 nm in diameter) in the presence of a glucose-terminated fluorinated oligo(ethylene glycol) ligand can spontaneously form size-segregated assemblies. The outermost layer of the assembly is composed of a single layer of small-sized GNPs, while the larger-sized GNPs are located in the interior, forming what is referred to as a yolk/shell assembly. Time course study reveals that small and large GNPs aggregate together, and these kinetically trapped aggregations were transformed into a size-segregated structure by repeating fusions. A yolk/shell structure was directly visualized in solution by X-ray laser diffraction imaging, indicating that the structure was truly formed in solution, but not through a drying process.

Despite tremendous progress in optoelectronic devices using lead perovskite (CH3NH3(+)PbI3(-)), there has been a paucity of mechanistic information on how photoactive micron-sized crystals of lead perovskite grow from a mixture of a layered crystal of lead(II) iodide and methylammonium iodide mediated by a polar solvent, DMSO or DMF. We report here that the whole process of the lead perovskite synthesis consists of a series of equilibria driven by reversible solvent participation involving a polymeric strip of plumbate(II) oligomer as a key intermediate. A significant finding includes quick decomposition of perovskite crystal upon exposure to DMSO or DMF at room temperature, where the solvent molecules act as a base to remove acidic ammonium iodide from the perovskite crystal. This observation accounts for the difficulty in controlling perovskite solar cell fabrication. Overall, the polar solvent is indispensible first to degrade a 2-D sheet of crystals of lead(II) iodide into 1-D fibrous intermediates and then to promote Oswald ripening of perovskite crystals. The detailed chemical information provided here will help to rationalize the photovoltaic device studies that have so far remained empirical and to open a new venue to a developing field of microscale lead perovskite devices, as illustrated by fabrication of photovoltaic devices and photodetectors.

In this work, we fabricated indium-free perovskite solar cells (SCs) using direct- and dry-transferred aerosol single-walled carbon nanotubes (SWNTs). We investigated diverse methodologies to solve SWNTs' hydrophobicity and doping issues in SC devices. These include changing wettability of poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (, Pedot: PSS), MoO3 thermal doping, and HNO3(aq) doping with various dilutions from 15 to 70 v/v% to minimize its instability and toxic nature. We discovered that isopropanol (IPA) modified, Pedot: PSS works better than surfactant modified, Pedot: PSS as an electron-blocking layer on SWNTs in perovskite SCs due to superior wettability, whereas MoO3 is not compatible owing to energy level mismatching. Diluted HNO3 (35 v/v%)-doped SWNT-based device produced the highest PCE of 6.32% among SWNT-based perovskite SCs, which is 70% of an indium tin oxide (ITO)-based device (9.05%). Its flexible application showed a PCE of 5.38% on polyethylene terephthalate (PET) substrate.

Organic solar cells have been regarded as a promising electrical energy source. Transparent and conductive carbon nanotube film offers an alternative to commonly used ITO in photovoltaics with superior flexibility. This communication reports carbon nanotube-based indium-free organic solar cells and their flexible application. Direct and dry deposited carbon nanotube film doped with MoO(x) functions as an electron-blocking transparent electrode, and its performance is enhanced further by overcoating with, Pedot: PSS. The single-walled carbon nanotube organic solar cell in this work shows a power conversion efficiency of 6.04%. This value is 83% of the leading ITO-based device performance (7.48%). Flexible application shows 3.91% efficiency and is capable of withstanding a severe cyclic flex test.

A solid solution of a 75:25 mixture of tetrabenzoporphyrin (BP) and dichloroacenaphtho[q]tribenzo[b,g,l]porphyrin (CABP) forms when they are generated in a matrix of (dimethyl(o-anisyl)silylmethyl)(dimethylphenylsilylmethyl)[60]fullerene. This solid solution provides structural and optoelectronic properties entirely different from those of either pristine compounds or a mixture at other blending ratios. The use of this BP:CABP solid solution for organic solar cell (OSC) devices resulted in a power conversion efficiency (PCE) value higher by 16 and 300% than the PCE values obtained for the devices using the single donor BP and CABP, respectively, in a planar heterojunction architecture. This increase originates largely from the increase in short circuit current density, and hence by enhanced charge carrier separation at the donor/acceptor interface, which was probably caused by suitable energy level for the solid solution state, where electronic coupling between the two porphyrins occurred. The results suggest that physical and chemical modulation in solid solution is beneficial as an operationally simple method to enhance OSC performance.

The stereochemistry of the C-glycosidic ellagitannins, vescalagin and castalagin, has been reinvestigated using computational methods. DFT calculations of their (1)H and (13)C NMR spectra, as well as TDDFT calculations of the ECD spectra of their des-hexahydroxydiphenoyl analogues, revealed that the structure of the triphenoyl moiety of vescalagin and castalagin should be revised.

In order to realize significant benefits from the assembly of solid-state materials from molecular cluster superatomic building blocks, several criteria must be met. Reproducible syntheses must reliably produce macroscopic amounts of pure material; the cluster-assembled solids must show properties that are more than simply averages of those of the constituent subunits; and rational changes to the chemical structures of the subunits must result in predictable changes in the collective properties of the solid. In this report we show that we can meet these requirements. Using a combination of magnetometry and muon spin relaxation measurements, we demonstrate that crystallographically defined superatomic solids assembled from molecular nickel telluride clusters and fullerenes undergo a ferromagnetic phase transition at low temperatures. Moreover, we show that when we modify the constituent superatoms, the cooperative magnetic properties change in predictable ways.