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Zhao Y.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Chen G.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Du Y.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Xu J.,CAS Hefei Key Laboratory of Materials for Energy Conversion | And 4 more authors.
Nanoscale | Year: 2014

We detail a facile method for enhancing the Raman signals of as-grown graphene on Cu foils by depositing gold nanoislands (Au Nis) onto the surface of graphene. It is found that an enhancement of up to 49 fold in the graphene Raman signal has been achieved by depositing a 4 nm thick Au film. The enhancement is considered to be related to the coupling between graphene and the plasmon modes of Au Nis, as confirmed by the finite element simulations. The plasmonic effect of the Au/graphene/Cu hybrid platform leads to a strong absorption at the resonant wavelength whose position shifts from visible light (640 nm) to near-infrared (1085 nm) when the thickness of Au films is increased from 2 nm to 18 nm. Finally, we demonstrate that hybrid substrates are reliable surface-enhanced Raman scattering (SERS) systems, showing an enhancement factor of ∼106 for dye molecules Rhodamine B and Rhodamine 6G with uniform and stable response and a detection limit of as low as 0.1 nM for Sudan III and Sudan IV. This journal is © The Royal Society of Chemistry.


PubMed | Florida State University, Nano Science and Technology Center, Tianjin University of Technology, Changzhou University and 2 more.
Type: Journal Article | Journal: Advanced materials (Deerfield Beach, Fla.) | Year: 2016

Hair-like-diameter superelastic conducting fibers, comprising a buckled carbon nanotube sheath on a rubber core, are fabricated, characterized, and deployed as weavable wires, biosensors, supercapacitors, and strain sensors. These downsized sheath-core fibers provide the demonstrated basis for glucose sensors, supercapacitors, and electrical interconnects whose performance is undegraded by giant strain, as well as ultrafast strain sensors that exploit strain-dependent capacitance changes.


Zhu C.,Nanjing Southeast University | Min H.,Nanjing Southeast University | Xu F.,Nanjing Southeast University | Xu F.,Brookhaven National Laboratory | And 5 more authors.
RSC Advances | Year: 2015

Utilizing inexpensive, high-efficiency counter electrodes (CEs) to replace the traditional platinum counterparts in dye-sensitized solar cells (DSSCs) is worthwhile. In this paper, we detail how we synchronously prepared composite CEs of CoS nanosheet arrays and reduced graphene oxide (rGO) layers for the first time via a low temperature, ultrafast one-step electrochemical strategy. With this approach, the whole fabrication process of the composite CEs was only a small percentage of the average time (∼15 hours) using other methods. The DSSC assembled with the rGO-CoS composite CE achieved an enhanced power conversion efficiency (PCE) of 8.34%, which is dramatically higher than 6.27% of pure CoS CE-based DSSC and even exceeds 7.50% of Pt CE-based DSSC. The outstanding PCE breakthrough is undoubtedly attributed to the enhancement in electrocatalytic ability of the rGO-CoS composite CE due to the incorporation of highly conducting rGO layers and the GO layers-induced growth of CoS nanosheet arrays with higher density and larger surface area. Therefore, lower charge-transfer resistance and higher exchange current density can be achieved as corroborated by the electrochemical impedance spectra (EIS) and Tafel polarization curves (TPCs). Further experiments also proved that the electrochemical strategy exhibited its universality of fabricating other graphene-enhanced chalcogenide functional composite films. © The Royal Society of Chemistry 2015.


Zhou X.,Leiden Institute of Chemistry | Zhou X.,China Pharmaceutical University | Laroche F.,Leiden University | Laroche F.,University of Aarhus | And 11 more authors.
Nano Research | Year: 2012

Efficient DNA delivery is essential for introducing new genes into living cells. However, effective virus-based systems carry risks and efficient synthetic systems that are non-toxic remain to be discovered. The bottle-neck in synthetic systems is cytotoxicity, caused by the high concentration of DNA-condensing compounds required for efficient uptake of DNA. Here we report a polyethyleneimine (PEI) grafted ultra-small graphene oxide (PEI-g-USGO) for transfection. By removing the free PEI and ensuring a high PEI density on small sized graphene, we obtained very high transfection efficiencies combined with very low cytotoxicity. Plasmid DNA could be transfected into mammalian cell lines with up to 95% efficiency and 90% viability. Transfection in zebrafish embryos was 90%, with high viability, compared to efficiencies of 30% or lower for established transfection technologies. This result suggests a novel approach to the design of synthetic gene delivery vehicles for research and therapy. © 2012 Tsinghua University Press and Springer-Verlag Berlin Heidelberg.


Zhao Y.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Li X.,Hefei University of Technology | Du Y.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Chen G.,CAS Hefei Key Laboratory of Materials for Energy Conversion | And 4 more authors.
Nanoscale | Year: 2014

The interactions between visible light and sub-nanometer gaps were investigated by sandwiching graphene between two layers of vertically stacked Au nanoparticles. The optical properties of such a hybrid film have been effectively tuned by embedding a monolayer graphene, enabling a suppressed transmission of ∼16% accompanied by a red-shift of the resonant wavelength. Finite element simulations have shown that the strong coupling between two layers of plasmonic Au nanoparticles leads to an electric field enhancement of up to 88 times in graphene defined vertical gaps, in contrast to that of 14 times in the horizontal gaps between Au nanoparticles formed in the fabrication process. In addition, the size of gaps and thus the field enhancement can be readily tuned by the number of graphene layers sandwiched between Au nanoparticles. When being used as surface-enhanced Raman scattering (SERS) substrates, the Au nanoparticle/graphene/Au nanoparticle structures have demonstrated high Raman enhancement factors of up to 1.6 × 108for RhB and 2.5 × 108for R6G, and a detection limit of as low as 0.1 nM for Sudan III and methylene blue molecules. This journal is © the Partner Organisations 2014.


Tang Q.,Dalian National Laboratory for Clean Energy | Tang Q.,University of Chinese Academy of Sciences | Tang Q.,Jiangnan Graphene Research Institute | Jiang L.,Dalian National Laboratory for Clean Energy | And 4 more authors.
ACS Catalysis | Year: 2014

In this article, manganese oxide nanorods with different crystalline structures, i.e., b-MnO2, α-Mn2O3, and a composite of Mn3O4 and α-Mn2O 3, were successfully synthesized via controlling the heat-treatment procedure starting from a manganese oxide composite, containing γ-MnOOH and Mn(OH)4. The oxygen reduction reaction (ORR) polarization curves measured by a rotating disk electrode (RDE) setup show that those MnO x catalysts with higher Mn valent states, i.e., γ-MnOOH and Mn(OH)4 composite and b-MnO2, exhibit better catalytic activity toward the ORR than those with lower Mn valences. Furthermore, we testify that the surface Mn valence of MnOx could be tuned by applying proper potential cycling to the MnOx electrode and thus leads to different activities, i.e., the MnOx surface is rich in Mn(II) after treatment at relatively negative potentials, resulting in degradation in ORR activity, while it is rich in Mn(IV) after treatment at positive potentials, resulting in improvement in activity. Compared with the heat-treatment approach, the electrochemical approach is more facile and energy-saving to tune the surface metal valence and thus ORR activity. © 2013 American Chemical Society.


Du Y.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Zhao Y.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Qu Y.,Graphene Technologies | Qu Y.,Jiangnan Graphene Research Institute | And 4 more authors.
Journal of Materials Chemistry C | Year: 2014

By simply coating graphene films on Au nanoparticles, the optical properties of the hybrid films are investigated. It is found that the coverage of a monolayer graphene film leads to a decreased transmittance of up to 15.8% in the visible range, much higher than the 2.3% transmittance loss for intrinsic graphene. At the same time, the plasmonic resonance of the hybrid films experiences a red-shift in resonance frequency and a broadening in the transmission dip. By means of finite element simulations, these observations are attributed to strong light-matter interaction at the interface between graphene and Au nanoparticles, as indicated by the increased absorption cross section and higher electric field intensity. The electron transfer between graphene and Au nanoparticles is confirmed by high resolution X-ray photoelectron spectroscopy studies. Furthermore, the enhanced electromagnetic hot spots at the interface between graphene and Au nanoparticles make such graphene-Au nanoparticle hybrid films cost-effective and high-performance surface-enhanced Raman scattering substrates for detecting organic molecules such as rhodamine-6G, for which an enhancement factor of ∼107 is achieved. © 2014 the Partner Organisations.


Wei X.,West Anhui University | Chen M.,Jiangnan Graphene Research Institute
Journal of the Chilean Chemical Society | Year: 2015

Herein we obtain CdSe-TiO2 composite, graphene-CdSe composite and graphene-TiO2 composite by using a facile hydrothermal method. The as-prepared composites are characterized by Brunauer emmett Teller (BET) surface area measurement, X-ray diffraction (XRD), scanning electron microscopy (SEM) with an energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), UV-vis diffuse refectance spectra (DRS). According to the decomposition results of methylene blue (MB) solution in dark, it can be observed that the graphene-CdSe composites show a very interesting character, self-decomposition effect of MB in dark.


Qin Y.,Changzhou University | Kong Y.,Changzhou University | Xu Y.,Changzhou University | Chu F.,Jiangnan Graphene Research Institute | And 2 more authors.
Journal of Materials Chemistry | Year: 2012

Highly loaded and ultrafine Pd nanoparticles were supported on graphene oxide (PdNPs-GO) via an in situ, simple and clean strategy on the basis of the direct redox reaction between Pd(OAc)2 and GO. A highly sensitive biosensor was developed for the detection of glucose based on the electrode modified with PdNPs-electrochemically reduced GO (PdNPs-ERGO). The glucose biosensor shows a wide linear range, low detection limit, good reproducibility and acceptable stability, providing a biocompatible platform for biosensing and biocatalysis. © The Royal Society of Chemistry 2012.


Dong G.,Leiden University | Dong G.,JiangNan Graphene Research Institute | Frenken J.W.M.,Leiden University
ACS Nano | Year: 2013

In situ scanning tunneling microscopy observations of graphene formation on Rh(111) show that the moiré pattern between the lattices of the overlayer and substrate has a decisive influence on the growth. The process is modulated in the large unit cells of the moiré pattern. We distinguish two steps: the addition of a unit cell that introduces one or more new kinks and the addition of further unit cells that merely advance the position of an existing kink. Kink creation is the rate-limiting step, with kink creation at small-angle, concave corners in the graphene overlayer exhibiting the lower barrier. © 2013 American Chemical Society.

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