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One 18-metal Eu(III) nanoring (size: 1.0 × 2.7 × 2.7 nm) was constructed as a rapid ratiometric fluorescent probe for the detection of dipicolinic acid with high sensitivity and selectivity, by using two types of polydentate organic ligands.

Direct π-extension by the Scholl reaction for solution-based growth of armchair edges in curved macrocyclic hydrocarbon nanostructures is a great challenge. To date, several attempts at direct π-extension of small highly strained macrocycles have failed. Herein, we report a fixed two-bond approach for direct functionalization of small strained macrocyclic nanorings. The reaction occurs selectively to produce large π-extended molecular crowns with high yields. The design of these precursors features two peripheral C–C bonds that are readily incorporated into the extended aromatic moiety to overcome strain-induced side reactions, such as 1,2-phenyl shift. The crown-shaped macrocycle 10 showed a significant redshift (∼100 nm for absorption) compared with its precursor. This synthesis strategy could pave the way towards the π-extension of strained conjugated macrocycles and their potential applications in electron-transport devices.

We report a novel strategy for the synthesis of Pt@Au nanorings possessing near-field focusing capabilities at the center through which single-particle surface enhanced Raman scattering could be readily observed. We utilized Pt@Au nanorings as a light-absorber; the absorbed light could be focused at the center with the aid of a Au nanoporous structure. We synthesized the Au nanolens structure through a Galvanic exchange process between Au ions and Ag block at the inner domain of the Pt@Au nanoring. For this step, Ag was selectively pre-deposited at the inner domain of the Pt@Au nanorings through electrochemical potential-tuned growth control and different surface energies with regard to the inner and outer boundaries of the nanoring. Then, the central nanoporous architecture was fabricated through the Galvanic exchange of sacrificial Ag with Au ions leading to the resulting Au nanoring with a Au nanoporous structure at the center. We monitored the shape-transformation by observing their corresponding localized surface plasmon resonance (LSPR) profiles. By varying the rim thickness of the starting Pt@Au nanorings, the inner diameter of the nanolens was accordingly tuned to maximize near-field focusing, which enabled us to obtain the reproducible and light-polarization independent measurements of single-particle SERS. Through theoretical simulation, the near-field electromagnetic field focusing capability was visualized and confirmed through single-particle SERS measurement showing an enhancement factor of 1.9 × 108 to 1.0 × 109., We synthesized a Au nanolens with electromagnetic near-field focusing capability by integrating a Au nanoporous structure at the center of the Pt@Au nanoring via synthetic steps of eccentric growth of Ag and nanoscale Galvanic exchange reaction.

An 18-metal lanthanide nanoring [Yb18(L1)8(HL2)2(OAc)20(MeOH)8(EtOH)6(H2O)4] (1), which shows a ratiometric fluorescent response to DPA, was constructed through the strategy of using two types of polydentate organic ligands. The addition of DPA increases the visible ligand-centered emission, but decreases the NIR lanthanide luminescence of 1. The limit of luminescent detection of 1 for DPA is 1.5 μM. The high fluorescence sensitivity of 1 to DPA is not affected by the existence of interferents such as aromatic carboxylates and ions.

The melamine·barbiturate H-bonded rosette motif is of comparable dimensions and symmetry to the cavity of a butadiyne-linked 6-porphyrin nanoring. Functionalisation of each of the barbiturate components and the pyrimidine components of a H-bonded rosette with a pyridine ligand leads to a self-assembled hexapyridine ligand, which binds cooperatively to the zinc porphyrin nanoring. UV-vis-NIR and 1H NMR experiments show that the 7-component assembly forms at concentrations at which neither the H-bonding interactions nor the zinc porphyrin–pyridine interactions are formed in the absence of one of the three components. The mean effective molarities of these rosette complexes are around 200 mM in chloroform at 298 K., Mixing barbiturates and pyrimidines equipped with pyridine ligands to leads to self-assembly of a hexadentate rosette ligand, which is complementary to a hexameric zinc porphyrin macrocycle.

Present herein is the first example of aluminium nanoring assembly by fatty acids. And the auxiliary alcohol sites can be modified either by monohydric alcohols (AlOC-33 to AlOC-35) or diols (AlOC-36 to AlOC-38). The monohydric alcohol modified ten-membered aluminium (Al10) rings are coplanar, while the diol modified ones possess a saddle-shaped configuration. Interestingly, the diol modified Al10 ring (AlOC-36) can convert into a coplanar ring (AlOC-33-B). AlOC-33-B possesses a similar molecular structure but a different supramolecular structure with AlOC-33. The structural transformation is confirmed to be a thermodynamically spontaneous process through density-functional theory (DFT) calculations.

Large-scale application of sustainable energy devices urgently requires cost-effective electrocatalysts to overcome the sluggish kinetics related to the oxygen evolution reaction (OER) under acidic conditions. Here, we first report the highly efficient electrocatalytic characteristics of α-Fe2O3 nanorings (NRs), which exhibits prominent OER electrocatalytic activity with lower overpotential of 1.43 V at 10 mA cm−2 and great stability in 1 M HCl, surpassing the start-of-the art Ir/C electrocatalyst. The significantly optimized OER activity of the α-Fe2O3 NRs mainly attributes to the synergistic effect of the excellent electrical conductivity and a large effective active surface because of their unique nanoring structure, disordered surface, and the dynamic stability of α-Fe2O3 NRs in acidic conditions.

Geometry design based plasmon hybridization represents an efficient means for pursuing desired spectral response and near-field enhancement in hybrid structures. Here, we propose to merge individual metal nanostructures into a superstructure to simultaneously realize plasmon mode inheritance and hybridization and electric near-field nanofocusing. As a model demonstration, we combine a metal nanoring supporting two localized surface plasmon resonances (LSPRs) and a metal nanocone sustaining one LSPR and one propagating surface plasmon polaritons (SPPs) mode into a hollow nanocone superstructure, and show numerically that such superstructure exhibits multiple plasmon resonance bands in the visible and near-infrared range and efficient nanofocusing of electric near-fields to the nanocone open apex. We further fabricate the designed superstructure with an ion-track membrane template method that allows for flexible control over relevant structural parameters by varying track etching time. Dark-field scattering measurements on single hollow nanocones confirm the presence of multiple plasmon resonances; surface-enhanced Raman spectroscopy further corroborates that the nanofocusing of electric fields plays a critical role in signal enhancement. We believe that such multi-resonant plasmonic superstructures with efficient near-field nanofocusing capability can find great potential in fundamental nonlinear optics and hot-carrier science studies and practical applications in surface-enhanced spectroscopies and broadband solar light harvesting.

Strong light–matter interaction at room temperature is significant for quantum optics, especially for exploring advanced nano-optical devices. We report herein a light–matter interaction in the strong coupling regime between plasmons confined within a single isolated bimetallic nanoring or nanocuboid and molecular excitons of J-aggregates under ambient conditions. We show that a bimetallic Au@Ag nanoring possesses larger enhanced electric field distribution than a Au@Ag nanocuboid, which enables bimetallic nanorings to couple with more excitons efficiently and overcome the large dissipation of the hybrid system. A large vacuum Rabi splitting of 200 meV was observed in this Au@Ag nanoring/J-aggregate hybrid. Finite-difference time-domain (FDTD) simulation and theoretical calculation show that there are ∼196 excitons in each Au@Ag nanoring/J-aggregate hybrid contributing to the coupling with a coupling constant of ∼111.3 meV, which is much higher than that of a single Au@Ag nanocuboid. Our work demonstrates that strong coupling can be realized via the enlargement of the overlap volume between excitons and plasmons, which can maximize the number of excitons contributing to coupling, giving rise to giant vacuum Rabi splitting. Our result provides additional flexibility to the experimental realization of novel plexcitonic architectures to attain strong coupling in an easily integrated and ultracompact platform.

Morphology evolution of calcite nanoparticles was investigated in detail during crystal growth induced by containing their aqueous slurry at a temperature of 95 °C. Formation of a single-crystalline nanoring that has a single cavity was confirmed soon after the slurry temperature was elevated to 95 °C. No templates were employed during the crystal growth process.

Using the linear combination of atomic orbitals real-time-propagation rt-TDDFT technique (LCAO-rt-TDDFT) and transition contribution maps, we study the optical and plasmonic features of a metal nanoring (made up of sodium atoms) with respect to the modulation in the ring thickness from a sharp edge (one-atom-thick) to a flat edge (four-atoms-thick). The birth of the localized surface plasmon resonance was accessed by many factors including the number of contributing electron-hole transitions, the relative strengths of these contributions, and the nature of the induced charge density oscillation. We reveal that the occurrence of a large number of contributing electron-hole transitions to an absorption peak cannot be treated as an indicator of plasmonicity. Nonetheless, plasmonicity can be accessed from the transition contribution map (occurrence of many spots with strong contributions and distributed on a large domain of energy) and from the profile of the induced charge density. Our results are useful for designing ultra-small plasmonic devices based on metal nanorings as building blocks.

The physical properties of conjugated cycloparaphenylene-based materials highly depend on their sizes, geometries, and functional groups. Herein we reported a facile strategy to synthesize novel multifunctionalized octamethoxy-[8]cycloparaphenylene (OMe-[8]CPP). Remarkably, an unusual hypsochromic shift in the emission spectrum was observed compared to its unfunctionalized nanoring. In addition, the photoinduced electron transfer process between OMe-[8]CPP and a naphthalene diimide electron acceptor is studied for the first time. OMe-[8]CPP will provide a suitable platform for subsequent synthesis manipulations to construct interesting and unprecedented functional nanocarbon structures.

The optical performance of two dimensional (2D) metallic nanoring arrays is inevitably affected by their substrate. This problem can be solved by using three dimensional (3D) nanorings, whose height is larger. However, most reported 3D-metallic nanoring arrays were prepared through focused ion beam lithography, which is high cost and low efficiency. Herein, we provided a new approach to fabricate highly ordered 3D-silver nanoring arrays (3D-AgNRAs) over a large area through multistep colloidal lithography combined with metal deposition. The specific structure of the 3D-AgNRAs could be facilely tuned by modulating the etching conditions. After gradual optimization of the 3D-AgNRAs’ structural parameters with respect to their optical and sensing performance, the optimized 3D-AgNRAs’ structural features were finally settled to be 1 μm period, 200 nm nanoring height, 300 nm silver layer thickness, 830 nm outer diameter, and 428 nm inner diameter. The optimized 3D-AgNRAs achieved high refractometric sensitivity of 1105.8 nm per RIU and relative sensitivity of 50.2% per RIU. Ultimately, the optimized 3D-AgNRAs were employed as an immunoassay substrate to prove their label-free biosensing potential in the future.

Inspiration from nature has driven the development and applications of greener inorganic nanomaterials prepared using biotemplates in the field of nanoscience. In this study, we report the superiority of using a biosynthesized silver nanoring material for CO formation in CO2 saturated KHCO3. Compared to bulk silver and free silver nanoparticles prepared by pure chemical reduction, this silver nanoring (assembled on tobacco mosaic virus coat protein) exhibits significantly enhanced activity and selectivity for the conversion of CO2 to CO. The highest CO faradaic efficiency reaches 95.0% at an overpotential of 910 mV. Additionally, the CO partial current density is 2.7-fold higher than that of the free silver nanoparticles. We believe that the improved catalytic performance is related to the structuring ligand effect of the protein. The numerous functional groups on the protein may tune the reaction activity by influencing the binding energies of the intermediate species from CO2 reduction or hydrogen evolution.

A short metallofullere-peapod of Y2@C79N⊂[4]CHBC was constructed. The strong confinement effect from the large π-extended [4]CHBC nanoring induces molecular orientation of the wrapped Y2@C79N, which can be sensed by a Y2@C79N spin probe. The low susceptibility of the spin phase memory time (Tm) for the Y2@C79N spin was also found in a confined space.

Nanostructured transition metal oxide anodes have attracted considerable attention for high-performance lithium-ion batteries (LIBs). However, their low rate capability and rapid capacity decline resulting from their low electronic conductivities and inevitable substantial volumetric changes prevent them from being commercialized as anodes for LIBs. Herein, we design a high-performance anode for LIBs consisting of a yolk–shell structured Fe2O3@C nanoring (NR) composite that comprises a NR-like Fe2O3 core entirely protected by a fine porous carbon (C) shell to overcome such obstacles. This advantageous yolk–shell structural design can buffer the significant volume variations of Fe2O3 cores without damaging the microstructure of the electrode. Thanks to the unique structural features, the as-built electrode shows a remarkable electrochemical performance, namely, a large specific capacity of 846 mA h g−1 after 100 cycles at 0.2 A g−1, a superior rate performance of 688 mA h g−1 at 4 A g−1, and a remarkable cycling life (300 cycles, 945 mA h g−1 at 4.0 A g−1). Hence, this electrode is much better than a pure Fe2O3 NR electrode.

Remote modulation of nanoscale biochemical processes in a living system using magnetic stimulation is appealing but is restricted by the lack of a highly efficient nanomediator which can deliver timely and effective response to biological molecules under an external magnetic field. Herein, we report the development of a novel nanocatalyst based on a ferrimagnetic vortex-domain nanoring (FVIO)-enzyme hybrid that enables real-time modulation of enzymatic catalysis under an alternating magnetic field (AMF). The role of the FVIO is to provide localized heating immediately upon exposure to an AMF, which efficiently and selectively promotes the activity of conjugated enzymes on the surface. The reaction rate of the as-fabricated FVIO-β-Gal hybrid was shown to be boosted up to 180% of its initial value by localized heat generated under an AMF of 550 Oe in less than 2 s and without heating up the bulk solution. Moreover, the degree of activity acceleration was shown to be tunable by increasing the strength of the AMF. The concept of remote magnetic stimulation of enzymatic reactions has been further applied to other enzymes (e.g. FVIO-KPC and FVIO-GOx), demonstrating the general applicability of this strategy. Since almost all metabolic processes in cells rely on enzymatic catalysis to sustain life, the FVIO-enzyme system developed in this work provides a valuable nanoplatform for spatiotemporally manipulating biochemical reactions, which might pave the way for future remote manipulation of living organisms.

Correction for ‘Biomass-derived interconnected carbon nanoring electrochemical capacitors with high performance in both strongly acidic and alkaline electrolytes’ by Xianjun Wei et al., J. Mater. Chem. A, 2017, 5, 181–188.

Cyclicparaphenylenediazenes (CPPDs) have drawn great attention due to their potential applications in molecular electronics and solar energy. However, to date, there have been no detailed structure and thermochemistry investigations on CPPDs. Herein, we used an integrated computational approach aimed at providing reliable structural and thermochemical information on novel CPPDs based photoswitchable molecular rings. The approach involves hybrid density functional theory calculation at the B3LYP/6-31+G(d,p) level coupled with homodesmotic reaction approach to calculate strain energies (SE) and standard enthalpies of formation of all cis and all trans isomers of [n]CPPDs (n = 2 to 8). The results show that strain energies and per-unit monomer of all cis-[n]CPPDs (n = 4 to 8) increase with increasing the numbers of Ph–NN linkages. However, an opposite trend was observed for all trans-[n]CPPDs (n = 4 to 8). The results were also compared with carbon nanoring structures i.e., cyclicparaphenyleneacetylenes (CPPAs) and cycloparaphenylenes (CPPs). The calculated highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO) energy gaps are in the range of 1.98 eV to 2.36 eV, indicating potential material for the construction of solar cells. The reported structures, SE, , and electronic properties of CPPDs can be also helpful to synthesize these novel materials.

A large-scale, uniform array of particle-in-aperture (PIA) hybrid architectures for highly reproducible surface-enhanced Raman spectroscopy (SERS) is rationally designed and prepared via electrostatic self-assembly of Au nanospheres and vertical deposition of Ag. By controlling the thickness of the Ag coating, polarization-independent ring-shaped hot spots with tunable width can be created around individual nanospheres, offering far higher Raman enhancements than a bare Au nanosphere array and a flat Ag film do. Three PIA substrates with different Ag thicknesses and an identical nanosphere diameter of 58 nm were investigated. Consequently, it is found that a 28 nm Ag coating enables the wavelength matching between the plasmonic coupling band and the laser line, leading to an enhancement factor of up to 4.5 × 106. Meanwhile, remarkable reproducibility of SERS signals is realized by ruling out the impact of anomalous hot spots. To this end, three guidelines are meticulously followed, i.e. using monodisperse Au nanospheres, distributing nanoring cavities evenly onto the substrate, and decoupling adjacent nanoparticles by isolating them far away from each other. This work offers a reliable strategy to fabricate high-performance SERS substrates in a simple, cost-effective and scalable manner, paving the way for practical sensing applications, such as quantitative SERS measurements.

We propose a novel and facile method to fabricate epitaxial ferroelectric BiFeO3 (BFO) nanorings using anodized alumina (AAO) template-assisted PLD and ion-beam etching. The morphology and dimensions of these nanorings are revealed by atomic force microscopy (AFM) and confirmed by transmission electron microscopy (TEM). The typical dimensions of the BFO nanorings are 12 nm inner diameter with 30 nm wall thickness and heights of around 10 nm. The X-ray diffraction (XRD), reciprocal space mapping (RSM) and TEM data demonstrate the epitaxial structure of these nanorings. Moreover, the ferroelectric properties are investigated by piezoresponse force microscopy (PFM), showing the polarization reversal behaviors of the isolated BFO nanorings, which have great potential applications for high-density non-volatile memory devices. In addition, this novel method could also be extended to other material systems (such as BaTiO3, ZnO and Au). Furthermore, the fabrication of high quality nanoring structures may open a pathway to explore related emerging physical phenomena (e.g., ferroelectric vortices).

International audience; A carbon nanotube-cobaloxime nanohybrid was prepared through supramolecular assembly of tailored polymerizable amphiphiles, leading to the coordination of cobalt on pyridine-coated nanotubes. This material was used as a catalyst for hydrogen evolution in fully aqueous media. This study provides a definitive asset regarding the stability of the pyridine-cobalt axial bond under H2 evolution turnover conditions.

Molecular dynamics simulations demonstrate that the cut defect can induce and guide the self-assembly of an isolated graphene nanoring (GNR) to form multi-layered funnel morphology. The vdW force is the driving force; the tangent component drives the self-assembly of GNR and the normal component adjusts and maintains the vertical distance between graphene layers, which is two times of the vdW radius. Moreover, the offset π-π stacking aids the adjacent layers to achieve the lowest energy of AB stacking. With different diameters of the annular GNRs, the final configurations experience multilayered cone, funnel and tube-shaped structures. It also illustrates the influence of temperature in the funnel-forming process. The wide gap with two edges beyond the cutoff distance of vdW force can utilize fullerenes to help and induce the assembly of the GNR. Cutting defect fissure would be a new way to induce the self-assembly of isolated graphene to design and fabricate new carbon nanostructures without impurities.

We report the dependence of gold nanoring (Au NR)-enhanced singlet oxygen (1O2) generation on localized surface plasmon resonance (LSPR) wavelength and separation distance between Au NR and photosensitizers. Using Au NR of tunable LSPR and poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) bilayers via layer-by-layer (LbL) assembly on Au NR as molecular spacers, we found that 1O2 generation from Al(III) phthalocyanine chloride tetrasulfonic acid (AlPcS4) conjugated on the Au NR can be optimized through proper combination of LSPR and the separation distance. More importantly, 1O2 enhancement follows a different correlation with the separation distance compared to that of AlPcS4 fluorescence enhancement. Our experimental findings are consistent with the prediction by boundary element method (BEM) calculations. Our study paves the way to the design of LSPR-enhanced 1O2 generation for improved efficacy of photodynamic therapy of cancers.

In this paper, we designed a 2D distance and rotation angle plasmon ruler based on Fano resonance of a trimer nanostructure, which consists of a concentric square nanoring–disk and an outside nanorod (CSRDR). The Fano dip energy and depth are fairly sensitive to the nanometer-scale displacements and rotations, when the nanodisk moves in all direction and rotates around its center. When the symmetry of the nanoring is broken, we can identify the moving and rotating direction of the nanodisk more accurately. We use the CSRDR nanostructure which supports a narrow line-width as a 2D plasmon ruler, which can enhance the sensitivity of a plasmon ruler significantly.

The molecular carbon nanoring, cycloparaphenylene (CPP), is fascinating as a new class of carbonaceous porous solids with the uniform structure of an all-benzene surface., The molecular carbon nanoring, cycloparaphenylene (CPP), is fascinating as a new class of carbonaceous porous solids with the uniform structure of an all-benzene surface. We explored the feasibility of [12]CPP as a carbon-based porous material and uncovered its unique adsorption properties due to its shape and highly nonpolar surface. Unlike other porous carbon solids, [12]CPP shows stepwise adsorption behaviors sensitive to the functionalities of the guest molecules. In situ powder X-ray diffraction and infrared spectra provided insights into how [12]CPP accommodates the guest molecules with structural deformation retaining its structural periodicity during the whole adsorption process, which exemplifies that this molecular nanoring represents an unprecedented carbon-based soft porous solid.

This work was financially supported by the National Nature Science Foundation of China (No: 51302280, 51574286), Natural Science Foundation in Qinghai province (No: 2014-ZJ- 936Q). CAS "Light of West China" Program and Youth Innovation Promotion Association (2016377), CAS. α-Fe2O3 nanoparticle with different morphologies, such as hollow spheres, nanotubes with limited {0001} plane exposed, nanoplates and nanorings with the {0001} plane predominantly exposed, have been synthesised by using NaH2PO4 and urea in a facile hydrothermal method. The mechanism of the morphology evolution from hollow sphere to nanoring has been investigated. It is proposed that the polymerisation of Fe3+/H2PO4− plays an important role in the formation of these morphologies. The adsorption of Cr (VI) from aqueous solution onto these α-Fe2O3 nanoparticles showed that the α-Fe2O3 with nanoring morphology has the highest removal efficiency, and the adsorption capacity reached to 16.9 mg/g. These results indicate that the adsorption mechanism of Cr (VI) onto hematite nanoparticles is a chemisorption process through doubly and triply coordinated hydroxyl groups on the outer surface of α-Fe2O3. Postprint

A hybrid nanostructure of Au–Ag nanorings prepared by decorating the surface of N-doped graphene (NG) was utilized as an electrocatalyst to construct a novel electrochemical sensor. Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were used to characterize the as-prepared composites. The Au–Ag nanorings/NG modified electrode exhibited a much better electrochemical response of rutin than that of Au/NG, Ag/NG and NG due to the synergetic catalytic effect between the Au–Ag nanorings and NG. Under optimal conditions, the electrochemical sensor of the Au–Ag nanorings/NG exhibited a wide linear range from 0.05 μM to 241.2 μM (S/N = 3) with a low detection limit of 0.01 μM. In addition, the proposed sensor also displayed good anti-interference ability and long-term stability, which had promising applications in bioassay analysis.

Herein we report the synthesis of a novel hexabenzocoronene-containing cycloparaphenylene carbon nanoring, cyclo[12]-paraphenylene[2]-2,11-hexabenzocoronenylene, by metal-mediated cross-coupling reactions. The nanoring was accomplished by rationally designed palladium-catalyzed coupling of diborylhexabenzocoronene and L-shaped cyclohexane units, followed by nickel-mediated C-Br/C-Br coupling and the aromatization of cyclohexane moieties. The structure was confirmed by NMR and HR-MS. Especially, the cycloparaphenylene structure is firstly observed by STM. The photophysical properties were studied using UV-Vis spectroscopy, photoluminescence (PL) spectroscopy, and theoretical calculations.

We fabricated a variety of reduced graphene oxide (RGO) nanoring arrays using Au@Pt nanoplates as a pattern mask. RGO nanoflakes were assembled into a 2-dimensional assembly at the water-oil interface, and then various shapes of Au@Pt nanoplates were utilized as a pattern mask in order to convert the RGO into circular, triangular, and hexagonal RGO nanorings.

We present a novel strategy capable of dynamically configuring the plasmon-induced transparency (PIT) effect with a polarization-dependent controllability based on a nanoring dimer array. The controllable coupling strength between the superradiant and subradiant modes is due to the polarization-dependent field distributions. It is shown that this dynamically controlled PIT is realized with a modulation depth as high as 95%, and a linear dependence of the coupling strength on polarization angle is deduced using a coupled-oscillator model. We believe that our results will inspire further exciting achievements that utilize various polarization states of the electromagnetic wave and pave a way towards applications using PIT with dynamic controllability such as slow light, optical nonlinearities and chemical/bio-sensing.

Self assembled binary nickel germanide nanorings are formed by annealing of a Ni/Ge/Si (100) film. Nickel germanide phase formation is confirmed by an X-ray diffraction (XRD) and X-ray photo electron spectroscopy (XPS) study. Rutherford backscattering spectrometry (RBS) measurement has been used to analyse germanide compositions and film thickness of the different annealed samples. Composition of the binary germanide phases from RBS simulation, agrees well with the XRD data. Atomic force microscopy (AFM) topography has been used to study nanoring evolution. Scanning electron microscopy (SEM) structures agree well with the AFM results. Nanoring formation mechanisms have also been explained with schematic structures. Nanostructures and lattice spacing of germanides have been studied from transmission electron microscopy (TEM) micrographs and selected area diffraction pattern (SAED) pattern.

Azobenzenes in particular have been proved to have a robust photo-response, in which their configuration can transform between the trans- and cis-form upon UV-visible irradiation. Accordingly, azobenzene-containing molecules are frequently applied in the design of the guests, involving so-called host-guest chemistry. In this paper, a novel photo-responsive nanoring host molecule ([4]AB) has been designed by introducing four azobenzene groups onto the ring, and interactions between the designed nanoring host and fullerenes C60 and C70 guests were investigated at both the M06-L/MIDI! as well as M06-2X/6-31G(d) level of theory. By analyzing the geometric characteristics and host-guest binding energies, it is revealed that the designed [4]AB with diameter ca. 13.4 Å is an ideal host molecule for the encapsulation of guests C60 and C70 fullerene. Meanwhile, inferred from UV-vis-NIR spectroscopy, the guest C60 and C70 could be facilely released from the cavity of the [4]AB via configuration transformation between trans- and cis-form of the host under 474 and 506 nm photo-irradiation, respectively. Frontier orbital features, weak interaction regions, infrared spectroscopy and (1)H NMR spectra have also been theoretically simulated. The present work would provide a new strategy for facile reversible encapsulation and release of fullerene guest by a novel nanoring host.

We have developed a novel hydrothermal method to fabricate Fe3O4 ring-like nanostructures via oriented attachment of Fe3O4 nanoparticles through intermediate platelets with incorporation of inorganic salts. The obtained samples were characterized by X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selective-area electron diffraction (SAED), high-resolution TEM (HRTEM) and vibrating-sample magnetometer (VSM). A reasonable mechanism based on the self-assembly of magnetic Fe3O4 nanoparticles on graphene nanosheets using inorganic ions as crystal growth modifiers is proposed. The intrinsic dipole–dipole interactions between the individual magnetic Fe3O4 nanoparticles act as the driving force for nanoring formation. Saturation moment of the superparamagnetic Fe3O4 nanorings is much higher than that of the corresponding disassembled nanoparticles. The enhancement of saturation moment is due to the oriented ring-like assembly with synergistic magnetism. This study could provide an additional tool for fabricating other nanostructures via oriented attachment.

Large-scale ordered arrays with dense hot spots are highly desirable substrates for practical applications such as surface-enhanced Raman scattering (SERS). In the past decade, most work has focused on using lateral gaps between two metal structures. However, the strength and density of the generated hot spots are limited to a 2D arrangement of nanostructures. In this work, we present a novel quasi-3D nanoring cavity structure, which contains a nanoring and a nanopillar in a nanohole. The fabrication is based on nanosphere lithography incorporated with dry etching and gold coating. Gold nanostructures with one layer (nanohole), 2 layers (nanohole + nanodisc), and 3 layers (nanohole + nanoring + nanopillar) were successfully fabricated and compared. The SERS performance of the three-layered nanostructures is about two orders of magnitude higher than the others. Finite-difference time-domain (FDTD) simulations show that incorporating nanopillars and nanorings into a nanohole array not only significantly increases the density of the hot spots but also achieves stronger electromagnetic field enhancements compared to a nanohole array. The simple fabrication of multilayered quasi-3D nanostructures provides a large-area and highly efficient SERS substrates for biological and chemical applications.

A new method based on the use of a core–shell nanoring amino-functionalized magnetic molecularly imprinted polymer (CS-NR-MMIP) as an adsorbent for matrix solid phase dispersion extraction (MSPD) has been developed for the highly selective and sensitive determination of ultratrace levels of BPA (Bisphenol A) by ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS). The adsorption and desorption conditions including the pH value, shaking time, and sample volume were investigated. The results showed that the adsorption property of the CS-NR-MMIP was highly pH dependent. Under the optimal experimental conditions, the enhancement factor of the CS-NR-MMIP MSPD procedure was 250, the limit of quantitation was 1 ng L−1, the linear range was between 1 ng L−1 and 200 ng L−1 and the correlation coefficient was 0.9992. The results showed that the developed method was faster, easier and more selective for extracting and enriching ultratrace BPA (nanogram per liter level) from water samples than the commercial C18 powder.

In this paper, we demonstrate a facile modified colloidal lithography (CL) method for the fabrication of morphology-controlled elliptical nanoring arrays (ERAs), which combines template-guided dewetting of polymer film and oxygen reactive ion etching. The elliptical templates were fabricated via a modified micromolding method using colloidal nanosphere arrays as the original templates, which were used to guide the dewetting of the polymer film to form ERAs. The height, aspect ratio and size of the resulting arrays could be controlled exactly. Moreover, through etching the underlying functional materials or mixing functional materials into the polymer film, elliptical ring arrays of different functional materials could also be fabricated, such as gold ERAs, silicon ERAs, ferromagnetic Fe–Ni composite ERAs, Fe3O4 ERAs and fluorescent ERAs. A potential application of the as-prepared functional ERAs is to provide a model for the fundamental research of anisotropic properties of the asymmetric patterned surface arrays and the fabrication of anisotropic surface pattern based devices for potential applications of shape-dependent optical and magnetic devices.

The first synthesis of a pyrene-containing carbon nanoring, cyclo[12]paraphenylene[2]-2,7-pyrenylene ([12,2]CPPyr), is described. Through a sequence of stepwise macrocyclization using Pd and Ni catalysts followed by aromatization of L-shaped cyclohexane units afforded a [12,2]CPPyr in five steps from commercially available compounds. The UV-vis absorption and fluorescence spectra as well as TD-DFT calculations clarified the unique photophysical and electronic properties of the [12,2]CPPyr.

Au nanoring@Ag core-shell nanostructures with controllable morphologies and tunable symmetries are synthesized via the seed-mediated growth of Ag onto a sole seed: a circular Au nanoring (AuNR). The 2D isotropic AuNR is prepared firstly by chemical etching, then by galvanic replacement with HAuCl4. By delicately altering the regrowth procedure and mixing the capping agents, different Ag triangular nanoplates with embedded AuNRs in different sizes and shapes can be obtained. Furthermore, by using a single capping agent, the growth of Ag on the AuNR can be preferentially confined to a lateral or vertical mode, to form eccentric nanoplates or nanocubes in both sequence sets at room temperature. Such nanostructures with precisely controllable shape evolution not only displayed unique optical properties, but also revealed the feasibility of breaking the original dimensions, and especially symmetry, at the nanoscale using seed-mediated growth. This paves the way for future applications including catalysis, diagnosis, plasmonics, and biological and chemical sensing.

We have studied the photoluminescence (PL) properties of [n]cycloparaphenylenes ([n]CPPs), which have simple string structures consisting of varying numbers of benzene rings, using steady-state and time-resolved PL spectroscopy. The PL lifetime decreased dramatically as the number of benzene rings increased, and increased with an increase in temperature. These results reveal that the exciton spreads beyond the benzene rings and that the temperature dependence of the PL lifetime is determined by thermal distribution of the excitons.

A novel core–shell nanoring amino-functionalized magnetic molecularly imprinted polymer (CS-NR-Mag-MIP) was synthesized by ultrasound-assisted suspension polymerization. CS-NR-Mag-MIP nanoparticles showed higher adsorption capacity, more specific selectivity, and faster binding ability than core–shell nanosphere amino-functionalized magnetic molecularly imprinted polymer (CS-NS-Mag-MIP) nanoparticles prepared by conventional mechanical agitation (CMA). The results indicate that CS-NR-Mag-MIP nanoparticles have promising potential for BPA enrichment and removal during water treatment operations.

A new gelator 1 that included m-methyl red was synthesized and fully characterized. It was found that the organogel of 1 was stable in DMSO even if the organogel was stimulated by acid or light. The organogel was thoroughly characterized using various microscopic techniques including field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), UV-vis and Fourier transform infrared (FTIR) spectra. The organogel exhibited tunable structures and optical properties under different stimulation. The regular nanoring structure was turned into microspheres after the organogel in DMSO was stimulated at 254 nm light or acid. At the same time, the color of molecule 1 in gel state and solution state was all changed after stimulation by light or acid. The hydrogen bonding and π-π stacking were found to be the main driving forces for gel formation. This dual-responsive gel held promise for soft materials application in upscale smart responsive materials.

This paper reports a novel and efficient strategy for fabricating sub-100 nm metal ring arrays using a simple printing process. Vertically aligned carbon nanotubes that are supported by hexagonally ordered channels of alumina matrices are used as a stamp to print nanoscale ring patterns, which is a very unique stamping platform that has never been reported. Using this strategy, uniform nanoring patterns of various metals can be directly printed onto a wide range of substrate surfaces under ambient conditions. Significantly, the size and interval of the printed nanorings can be systematically tuned by controlling the ring-shaped tip dimensions of the pristine stamps. An advanced example of these printable nanoscale metal ring arrays is explicitly embodied in this work by investigation of the plasmon resonances of metal nanorings with different sizes and intervals.

We have successfully developed a facile two-step anodization combined layer-by-layer (LBL) self-assembly route for rapid fabrication of well-defined metal-TiO(2) nanoring/nanotube combined nanostructures, i.e. M/T-NRNT (M = Au, Ag, Pt). These hierarchically self-assembled hybrid systems are demonstrated to exhibit versatile photocatalytic and catalytic reduction capabilities.

In this paper, we show that by varying the voltages during two-step anodization the morphology of the hierarchical top-layer/bottom-tube TiO2 (TiO2 NTs) can be finely tuned between nanoring/nanotube, nanopore/nanotube, and nanohole–nanocave/nanotube morphologies. This allows us to optimize the photoelectrochemical (PEC) water splitting performance on the hierarchical TiO2 NTs. The optimized photocurrent density and photoconversion efficiency in this study, occurring on the nanopore/nanotube TiO2 NTs, were 1.59 mA cm−2 at 1.23 V vs. RHE and 0.84% respectively, which are the highest values ever reported on pristine TiO2 materials under illumination of AM 1.5G. Our findings contribute to further improvement of the energy conversion efficiency of TiO2-based devices.

We presented, for the first time, the evidence of loop-by-loop self-coiling of a nanobelt to form single-crystal Na2Ti6O13 nanorings with diameters of several micrometres. The winding nanobelts, with thickness of about 15 nm and widths of 100–500 nm, grow along their [010] crystallographic directions, and coherently match at ±(200) crystallographic planes. The driving force of such a coherent match is suggested to be the minimization of local electrostatic energy introduced by the cations and anions. We also discussed the dependence of the nanoring's yield on the thickness of the nanobelts, which affects the elastic deformation energy and misfit energy of the rings.

Here we highlight the recent advances in synthesizing some novel nanostructures where polar surfaces and the associated electrostatic interactions appear to play critical roles. Some examples, including ZnO nanospring and nanoring, AlN nanonecklace, and CrSi2 nanoweb, are discussed.

Tailed-Fe(2)O(3) ring arrays are fabricated by solution-dipping on a colloidal monolayer template. The influence of synthesis parameters on the quality of nanostructures has been investigated. The ring size can be controlled by changing the precursor concentration and varying the annealing time of the polystyrene sphere colloidal monolayer. In addition, the edge of the rings is sensitive to the surface tension of precursor solution, and high quality ordered ring arrays can be obtained by tuning the surface tension. This strategy allows the fabrication of specific metal oxides ring arrays with high quality and uniform morphology.

A silicon-containing diblock copolymer, poly(styrene)-b-poly(dimethylsiloxane) (PS-PDMS), with PDMS cylinders in a PS matrix has been synthesized through sequential anionic polymerization. PS-PDMS thin film was prepared by spin coating on silicon wafer. Perpendicular PDMS cylinders in the PS-PDMS thin film can be obtained by solvent annealing. The PS-PDMS thin film was employed as template for the formation of core-shell cylinder thin films through surface reconstruction. By taking advantage of the silicon-containing character, silicon oxy carbide nanopattern can be fabricated due to the crosslinking of PDMS blocks and the degradation of PS blocks through one-step oxygen plasma treatment. As a result, the formation of silicon oxy carbide nanoring arrays can be achieved. This method provides a convenient way to create silicon oxy carbide nanoring arrays from diblock copolymers.

We report a novel and versatile approach for fabricating ordered nanoring arrays of metals, metal oxides, and other inorganic materials with diameter of sub-50 nm by loading the salt precursors in P4VP cores of PS-b-P4VP thin film and exposing these to methanol vapor which results in the P4VP blocks shrinking to form nanorings.