Chunru Wang

Synthesis of CuO/graphene nanocomposite as a high-performance anode material for lithium-ion batteries

An optimized nanostructure design for electrode materials for high-performance lithium-ion batteries was realized by introducing three-dimensional (3D) graphene networks into transition metal oxide nanomicrostructures. A CuO/graphene composite was selected as a typical example of the optimized design. Self-assembled CuO and CuO/graphene urchin-like structures have been successfully synthesized by a simple solution method and investigated with SEM, TEM, XRD, and electrochemical measurements. The CuO/graphene nanocomposite exhibits a remarkably enhanced cycling performance and rate performance compared with pure CuO urchin-like structure when being used as anode materials in lithium-ion batteries. During all the 100 discharge-charge cycles under a current density of 65 mA g−1, the CuO/graphene electrode can stably deliver a reversible capacity of ca. 600 mA h g−1. At a high current density of 6400 mA g−1, the specific charge capacity of the CuO/graphene nanocomposite is still as high as 150 mA h g−1, which is three times larger than that of graphene (48 mA h g−1), while that of CuO is nearly null under the same current density. The enhancement of the electrochemical performance could be attributed to the 3D electrically conductive networks of graphene as well as the unique nanomicrostructure of the CuO/graphene nanocomposite in which the CuO nanomicroflowers are enwrapped by a thin layer of graphene as an elastic buffer.

Fully Conjugated Tri(perylene bisimides): An Approach to the Construction of n-Type Graphene Nanoribbons

We present an experimental study encompassing synthesis and characterization of fully conjugated tri(perylene bisimides) (triPBIs), having 19 six-membered carbon rings in the core and six imide groups at the edges. Two structural isomers of triPBIs resulting from the two probable coupling positions were successfully separated by HPLC. To assist the identification of the two structural isomers, quantum-chemical calculations of electronic structure, NMR, and optical spectra were carried out. Calculations predict stable helical and nonhelical configurations for both triPBIs isomers and allow the assignment of triPBIs 6 unequivocally to the most bathochromically shifted absorption spectrum. Increasing the number of PBI units in oligo-PBIs leads to an expansion of the pi system, in turn associated with a reduction of the transport and optical band gaps, and a remarkable increase in electron affinities, which make oligo-PBIs promising n-type functional components in optoelectronic devices.

Site‐Selective Fabrication of Two‐Dimensional Fullerene Arrays by Using a Supramolecular Template at the Liquid‐Solid Interface

have been successfully used to direct theformation of ordered fullerene arrays. In this way theinterfullerene distance and symmetry of the arrangementaresolelydeterminedbythemoleculartemplateandcanbechanged by adjusting its structure. More importantly, inter-actions between fullerenes can also be modified with thisstrategy.Wehavedesignedandsynthesizedatetraacidicazoben-zene molecule NN4A (Figure1a) that exclusively formsKagomopennetworkswithtwotypesofcavitiesthathavedifferent size and symmetry at the liquid–solid interface.These cavities are capable of accommodating fullerenemolecules as guest species. Herein, we examine the siteselectivityofthenetworksfordifferentfullerenes,afeaturewhichhasnotbeenobservedforothersystemsatliquid–solidinterfaces.Azobenzenederivativesaretypicalphotochromiccompoundsthathaveawiderangeofpotentialapplications,including for optical switching, holographic storage, lightharvesting, long-term energy storage, and nonlinear opticalmaterials.

Study of the Inhibitory Effect of Water-Soluble Fullerenes on Plant Growth at the Cellular Level

The effect of water-soluble fullerene C(70)(C(COOH)(2))(4-8) on plant growth was investigated, using the transgenic seedling lines expressing fluorescent makers. The retarded roots with shortened length and loss of root gravitropism were observed for seedlings grown in the fullerene-containing medium. Fluorescence imaging revealed the abnormalities of root tips in hormone distribution, cell division, microtubule organization, and mitochondrial activity. The study of the inhibitory effects at the cellular level provides new information on the phytotoxicity mechanism of fullerene.

Conjugation of a Water-Soluble Gadolinium Endohedral Fulleride with an Antibody as a Magnetic Resonance Imaging Contrast Agent

Water-soluble gadofullerides exhibited high efficiency as magnetic resonance imaging (MRI) contrast agents. In this paper, we report the conjugation of the newly synthesized gadofulleride, Gd@C82O6(OH) 16(-)(NHCH2CH2COOH)8, with the antibody of green fluorescence protein (anti-GFP), as a model for tumor targeted imaging agents based on endohedral metallofullerenes. In this model system, the activity of the anti-GFP conjugate can be conveniently detected by green fluorescence protein (GFP), leading to in vitro experiments more direct and facile than those of tumor antibodies. Objective-type total internal reflection fluorescence microscopy revealed that each gadofulleride aggregate conjugated on average five anti-GFPs, and the activity of anti-GFPs was preserved after conjugation. In addition, the gadofulleride/antibody conjugate exhibited higher water proton relaxivity (12.0 mM (-1) s (-1)) than the parent gadofulleride aggregate (8.1 mM (-1) s (-1)) in phosphate buffered saline at 0.35 T, as also confirmed by T1-weighted images of phantoms. These observations clearly indicate that the synthesized gadofulleride/antibody conjugate not only has targeting potential, but also exhibits higher efficiency as an MRI contrast agent.

Template-free solution growth of highly regular, crystal orientation-ordered C60 nanorod bundles

Crystal orientation-ordered C60 nanorod bundles have been assembled, where each C60 nanorod maintains its individual shape and identity with unpolymerized bucky balls and all of the nanorods are vertically aligned with a high density. The key to this lies in the assembly of the C60 nanorod bundles from the nanoscopic to microscopic and macroscopic scale. The novel structure of C60 nanorod bundles leads to a high photoresponse, which is promising for applications in optical devices.

Effects of fullerene derivatives on bioluminescence and application for protease detection

The effects of two C(60) derivatives: C(60)[C(COOH)(2)](3) and C(60)(NH(2))(x)(OH)(y), have been investigated on the bioluminescence of humanized Gaussia luciferase (hGluc) for the first time. Utilizing the dual properties of carboxyl C(60) with luminescence quenching and free radicals scavenging, a novel BRET system was constructed for protease detection with high sensitivity.

Strongly enhanced current-carrying performance in MgB2 tape conductors by C60 doping

By utilizing C60 as a viable alternative dopant, we demonstrate a simple and industrially scalable route that yields a 10∼15-fold improvement in the in-high-field current densities of MgB2 tape conductors. For example, a Jc value higher than 4×104u2002A/cm2 (4.2 K, 10 T), which exceeds that for NbTi superconductor, can be realized on the C60 doped MgB2 tapes. It is worth noting that this value is even higher than that fabricated using strict high energy ball milling technique under Ar atmosphere. At 20 K, Hirr was ∼10u2002T for C60 doped MgB2 tapes. A large amount of nanometer-sized precipitates and grain boundaries were found in MgB2 matrix. The special physical and chemical characteristics of C60, in addition to its C containing intrinsic essence, are a key point in enhancing the superconducting performance of MgB2 tapes.

The effects of annealing on the structures and electrical conductivities of fullerene-derived nanowires

We have succeeded in fusing C60 clusters into one-dimensional nanowires by electrophoretic deposition using porous anodic aluminium oxide (AAO) membranes as templates. The C60 clusters are introduced through a dc electric field and polymerized in the channels. Here we present the results on the effects of annealing on the structures and electrical conductivities of the fullerene-derived nanowires. By changing the annealing temperature we found that the grain sizes became large at 523 K and 673 K while damaged to amorphous carbon resulted at 823 K, as determined by Fourier transform infrared (FTIR) absorption spectroscopy, X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM). The measurements of their electrical conductivities show their semiconducting behavior with resistance varied by more than two orders of magnitude after annealing.

Indan-C60: from a crystalline molecule to photovoltaic application

Crystalline Indan-C60 and its photovoltaic application were studied. Microsheets and aloe-like micro-nano superstructures can be assembled from Indan-C60. Indan-PC61BM derived from Indan-C60 was further investigated as an acceptor for OPV devices, which shows a higher Voc, FF, and PCE than those obtained using PC61BM.