ORCID Profile
0000-0001-5309-8484
Current Organisation
Queensland University of Technology (QUT)
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Publisher: American Chemical Society (ACS)
Date: 05-02-2014
DOI: 10.1021/NL4038592
Abstract: Distinct from pure graphene, N-doped graphene (GN) has been found to possess high rate capability and capacity for lithium storage. However, there has still been a lack of direct experimental evidence and fundamental understanding of the storage mechanisms at the atomic scale, which may shed a new light on the reasons of the ultrafast lithium storage property and high capacity for GN. Here we report on the atomistic insights of the GN energy storage as revealed by in situ transmission electron microscopy (TEM). The lithiation process on edges and basal planes is directly visualized, the pyrrolic N "hole" defect and the perturbed solid-electrolyte-interface configurations are observed, and charge transfer states for three N-existing forms are also investigated. In situ high-resolution TEM experiments together with theoretical calculations provide a solid evidence that enlarged edge {0002} spacings and surface hole defects result in improved surface capacitive effects and thus high rate capability and the high capacity are owing to short-distance orderings at the edges during discharging and numerous surface defects the phenomena cannot be understood previously by standard electron or X-ray diffraction analyses.
Publisher: American Chemical Society (ACS)
Date: 10-01-2022
DOI: 10.1021/ACS.NANOLETT.1C03796
Abstract: Free-standing few-layered MoSe
Publisher: American Chemical Society (ACS)
Date: 29-02-2016
DOI: 10.1021/ACS.NANOLETT.6B00057
Abstract: As the most promising anode material for sodium-ion batteries (SIBs), elemental phosphorus (P) has recently gained a lot of interest due to its extraordinary theoretical capacity of 2596 mAh/g. The main drawback of a P anode is its low conductivity and rapid structural degradation caused by the enormous volume expansion (>490%) during cycling. Here, we redesigned the anode structure by using an innovative methodology to fabricate flexible paper made of nitrogen-doped graphene and amorphous phosphorus that effectively tackles this problem. The restructured anode exhibits an ultrastable cyclic performance and excellent rate capability (809 mAh/g at 1500 mA/g). The excellent structural integrity of the novel anode was further visualized during cycling by using in situ experiments inside a high-resolution transmission electron microscope (HRTEM), and the associated sodiation/desodiation mechanism was also thoroughly investigated. Finally, density functional theory (DFT) calculations confirmed that the N-doped graphene not only contributes to an increase in capacity for sodium storage but also is beneficial in regards to improved rate performance of the anode.
Publisher: Elsevier BV
Date: 03-2018
Publisher: Springer Science and Business Media LLC
Date: 04-2015
DOI: 10.1038/AM.2015.23
Publisher: American Chemical Society (ACS)
Date: 11-07-2023
DOI: 10.1021/JACS.3C03961
Publisher: Elsevier BV
Date: 12-2019
Publisher: Elsevier BV
Date: 09-2013
Publisher: Wiley
Date: 02-03-2014
Publisher: Elsevier BV
Date: 09-2021
Publisher: Elsevier BV
Date: 06-2016
Publisher: IOP Publishing
Date: 23-03-2015
DOI: 10.1088/0957-4484/26/15/154001
Abstract: A high-precision technique was utilized to construct and characterize axial nanowire heterojunctions inside a high-resolution transmission electron microscope (HRTEM). By an in-tandem technique using an ultra-sharp tungsten probe as the nanomanipulator and an optical fiber as the optical waveguide the nanoscale CdS -Si axial nanowire junctions were fabricated, and in situ photocurrents from them were successfully measured. Compared to a single constituting nanowire, the CdS -Si axial nanowire junctions possess a photocurrent saturation effect, which protects them from damage under high voltages. Furthermore, a set of experiments reveals the clear relationship between the saturation photocurrent values and the incident light intensities. The applied technique is expected to be valuable for bottom-up nanodevice fabrications, and the regarded photocurrent saturation feature may solve the Joule heating-induced failure problem in nanowire optoelectronic devices caused by a fluctuating bias.
Publisher: Wiley
Date: 12-02-2014
Abstract: The application of nanofilm networks made of branched ZnS-ZnO nanostructures as a flexible UV photodetector is demonstrated. The fabricated devices show excellent operational characteristics: tunable spectral selectivity, widerange photoresponse, fast response speed, and excellent environmental stability.
Publisher: Wiley
Date: 02-12-2017
Abstract: A novel carbon structure, highly branched homogeneous-N-doped graphitic (BNG) tubular foam, is designed via a novel N, N-dimethylformamide (DMF)-mediated chemical vapor deposition method. More structural defects are found at the branched portions as compared with the flat tube domains providing abundant active sites and spacious reservoirs for Li
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TA03555F
Abstract: Sb 2 S 3 –rGO potassium-ion battery anode material is synthesised by the peroxide route and is evaluated in two non-aqueous electrolytes.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8TA12511B
Abstract: The role of the carbonaceous component in the excellent (de)lithiation properties of a ZnO/carbon anode material, as revealed by in situ TEM.
Publisher: AIP Publishing
Date: 13-03-2017
DOI: 10.1063/1.4978603
Abstract: The luminescence centers in cadmium sulfide (CdS) nanowires are mapped through cathodoluminescence experiments inside a high resolution transmission electron microscope. This is made possible by positioning an optical fiber within a few micrometers of the area of interest and scanning the focused electron beam while simultaneously collecting the generated photons. The results reveal the distribution of luminescence centers in this material with nanometer-precision. Furthermore, these centers are associated with various intrinsic defects in CdS, which allows mapping these defects even when their concentration is far below the level detectable by other traditional techniques.
Publisher: Elsevier BV
Date: 02-2021
Publisher: American Chemical Society (ACS)
Date: 13-07-2022
Publisher: American Chemical Society (ACS)
Date: 02-07-2014
DOI: 10.1021/NN502999G
Abstract: Silicon has a diamond-like cubic crystal lattice for which two-dimensional (2D) nanometer thickness nanosheet crystallization appears not to be trivial. However, in this issue of ACS Nano, the group led by Heon-Jin Choi demonstrates the gas-phase dendritic growth of Si nanosheets, only 1 to 13 nm thick. Moreover, such nanosheets display strong thickness-dependent photoluminescence in a visible range with red, green, and blue emission each documented.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5NR05625J
Abstract: We designed a novel pollutant capturing surface enhanced Raman spectroscopy (SERS) substrate based on boron nitride microfibers uniformly decorated with silver nanoparticles.
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7TA08431E
Abstract: 100% faradaic efficiency is achieved in electrochemical reduction of CO 2 to CO via coupling between ZIFs and CNTs.
Publisher: Wiley
Date: 19-05-2017
Abstract: Engineering of the optical, electronic, and magnetic properties of hexagonal boron nitride (h-BN) nanomaterials via oxygen doping and functionalization has been envisaged in theory. However, it is still unclear as to what extent these properties can be altered using such methodology because of the lack of significant experimental progress and systematic theoretical investigations. Therefore, here, comprehensive theoretical predictions verified by solid experimental confirmations are provided, which unambiguously answer this long-standing question. Narrowing of the optical bandgap in h-BN nanosheets (from ≈5.5 eV down to 2.1 eV) and the appearance of paramagnetism and photoluminescence (of both Stokes and anti-Stokes types) in them after oxygen doping and functionalization are discussed. These results are highly valuable for further advances in semiconducting nanoscale electronics, optoelectronics, and spintronics.
Publisher: American Chemical Society (ACS)
Date: 09-09-2016
DOI: 10.1021/ACS.NANOLETT.6B01614
Abstract: We demonstrate that high resolution transmission electron microscopy (HRTEM) paired with light illumination of a s le and its electrical probing can be utilized for the in situ study of initiated photocurrents in free-standing nanowires. Morphology, phase and crystallographic information from numerous in idual CdS nanowires is obtained simultaneously with photocurrent measurements. Our results indicate that elastically bent CdS nanowires possessing a wurtzite structure show statistically unchanged values of ON/OFF (photocurrent/dark current) ratios. Photocurrent spectroscopy reveals red shifts of several nanometers in the cutoff wavelength after nanowire bending. This results from deformation-induced lattice strain and associated changes in the nanowire band structure, as confirmed by selected area electron diffraction (SAED) analyses and density functional tight binding (DFTB) simulations. The ON/OFF ratio stabilities and photocurrent spectroscopy shift of bent CdS nanowires are important clues for future flexible electronics, optoelectronics, and photovoltaics.
Publisher: AIP Publishing
Date: 07-2019
DOI: 10.1063/1.5108849
Abstract: The thermal stability of all-inorganic halide perovskites is their key advantage over organic/hybrid halide perovskites. Here, in situ high-resolution transmission electron microscopy (HRTEM) was used to directly investigate crystallography dynamics of a CsPbBr3 perovskite at high temperature (up to 690 K). In high vacuum TEM conditions (∼10−5 Pa), CsPbBr3 nanocrystals possessed superb stability at temperatures below 690 K. By sealing the crystals in amorphous carbon, their melting and solidification processes were directly observed at temperatures of 840 K and 838 K, respectively. This study should be valuable for future perovskite-containing solar cells, lasers, light-emitting diodes, and photodetectors working at high temperatures.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6TA00768F
Abstract: Sulfurated carbon catalysts from pyrolysis of zeolitic imidazolate frameworks demonstrate oxygen reduction activity surpassing commercially available Pt/C in alkaline media.
Publisher: Wiley
Date: 22-11-2016
Abstract: A high-performance nonprecious-metal oxygen-reduction electrocatalyst is prepared via in situ growth of bimetallic zeolitic imidazolate frameworks on multiwalled carbon nanotubes (CNTs) followed by adsorption of furfuryl alcohol and pyrolysis. The networking boosts the conductivity and performance in a polymer electrolyte membrane fuel cell, yielding a maximal power density of 820 mW cm
Publisher: Elsevier BV
Date: 12-2015
Publisher: Springer Science and Business Media LLC
Date: 12-02-2020
Publisher: American Chemical Society (ACS)
Date: 21-03-2022
Publisher: American Chemical Society (ACS)
Date: 25-08-2023
Publisher: Elsevier BV
Date: 04-2015
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CC39273B
Abstract: A high-quality SnO(2) hollow-sphere nanofilm based flexible photodetector was constructed via'water-oil' interfacial assembling. The photodetector showed high sensitivity, superb stability, and was also able to bear significant external mechanical forces.
Publisher: Elsevier BV
Date: 10-2021
Publisher: American Chemical Society (ACS)
Date: 07-07-2020
Publisher: Wiley
Date: 08-07-2013
Abstract: Electrospun ZnO-SnO2 heterojunction nanofibers are demonstrated to be promising candidates for easily assembled fully transparent high-performance photodetectors.
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3NH00348E
Publisher: AIP Publishing
Date: 31-08-2015
DOI: 10.1063/1.4929812
Abstract: Photocurrent spectroscopy of in idual free-standing ZnO nanowires inside a high-resolution transmission electron microscope (TEM) is reported. By using specially designed optical in situ TEM system capable of scanning tunneling microscopy probing paired with light illumination, opto-mechano-electrical tripling phenomenon in ZnO nanowires is demonstrated. Splitting of photocurrent spectra at around 3.3 eV under in situ TEM bending of ZnO nanowires directly corresponds to nanowire deformation and appearance of expanded and compressed nanowire sides. Theoretical simulation of a bent ZnO nanowire has an excellent agreement with the experimental data. The splitting effect could be explained by a change in the valence band structure of ZnO nanowires due to a lattice strain. The strain-induced splitting provides important clues for future flexible piezo-phototronics.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0GC01081B
Abstract: An ionic liquid-based green synthesis of perovskite nanocrystals towards practical applications.
Publisher: American Chemical Society (ACS)
Date: 16-12-2016
Abstract: Construction of cellular architectures has been expected to enhance materials' mechanical tolerance and to stimulate and broaden their efficient utilizations in many potential fields. However, hitherto, there have been rather scarce developments in boron nitride (BN)-type cellular architectures because of well-known difficulties in the syntheses of BN-based structures. Herein, cellular-network multifunctional foams made of interconnective nanotubular hexagonal BN (h-BN) architectures are developed using carbothermal reduction-assisted in situ chemical vapor deposition conversion from N-doped tubular graphitic cellular foams. These ultralight, chemically inert, thermally stable, and robust-integrity (supporting about 25,000 times of their own weight) three-dimensional-BN foams exhibit a 98.5% porosity, remarkable shape recovery (even after cycling compressions with 90% deformations), excellent resistance to water intrusion, thermal diffusion stability, and high strength and stiffness. They remarkably reduce the coefficient of thermal expansion and dielectric constant of polymeric poly(methyl methacrylate) composites, greatly contribute to their thermal conductivity improvement, and effectively limit polymeric composite softening at elevated temperatures. The foams also demonstrate high-capacity adsorption-separation and removal ability for a wide range of oils and organic chemicals in oil/water systems and reliable recovery under their cycling usage as organic adsorbers. These created multifunctional foams should be valuable in many high-end practical applications.
Publisher: American Chemical Society (ACS)
Date: 21-02-2019
DOI: 10.1021/ACS.NANOLETT.9B00263
Abstract: Aluminum nitride (AlN) has a unique combination of properties, such as high chemical and thermal stability, nontoxicity, high melting point, large energy band gap, high thermal conductivity, and intensive light emission. This combination makes AlN nanowires (NWs) a prospective material for optoelectronic and field-emission nanodevices. However, there has been very limited information on mechanical properties of AlN NWs that is essential for their reliable utilization in modern technologies. Herein, we thoroughly study mechanical properties of in idual AlN NWs using direct, in situ bending and tensile tests inside a high-resolution TEM. Overall, 22 in idual NWs have been tested, and a strong dependence of their Young's moduli and ultimate tensile strengths (UTS) on their growth axis crystallographic orientation is documented. The Young's modulus of NWs grown along the [101̅1] orientation is found to be in a range 160-260 GPa, whereas for those grown along the [0002] orientation it falls within a range 350-440 GPa. In situ TEM tensile tests demonstrate the UTS values up to 8.2 GPa for the [0002]-oriented NWs, which is more than 20 times larger than that of a bulk AlN compound. Such properties make AlN nanowires a highly promising material for the reinforcing applications in metal matrix and other composites. Finally, experimental results were compared and verified under a density functional theory simulation, which shows the pronounced effect of growth axis on the AlN NW mechanical behavior. The modeling reveals that with an increasing NW width the Young's modulus tends to approach the elastic constants of a bulk material.
Publisher: Elsevier BV
Date: 09-2015
Publisher: Wiley
Date: 30-11-2019
Publisher: American Chemical Society (ACS)
Date: 29-05-2018
DOI: 10.1021/ACS.LANGMUIR.8B00401
Abstract: Metal-semiconductor hybrid nanomaterials are becoming increasingly popular for photocatalytic degradation of organic pollutants. Herein, a seed-assisted photodeposition approach is put forward for the site-specific growth of Pt on Au-ZnO particles (Pt-Au-ZnO). A similar approach was also utilized to enlarge the Au nanoparticles at epitaxial Au-ZnO particles (Au@Au-ZnO). An epitaxial connection at the Au-ZnO interface was found to be critical for the site-specific deposition of Pt or Au. Light on-off photocatalysis tests, utilizing a thiazine dye (toluidine blue) as a model organic compound, were conducted and confirmed the superior photodegradation properties of Pt-Au-ZnO hybrids compared to Au-ZnO. In contrast, Au-ZnO type hybrids were more effective toward photoreduction of toluidine blue to leuco-toluidine blue. It was deemed that photoexcited electrons of Au-ZnO (Au, ∼5 nm) possessed high reducing power owing to electron accumulation and negative shift in Fermi level/redox potential however, exciton recombination due to possible Fermi-level equilibration slowed down the complete degradation of toluidine blue. In the case of Au@Au-ZnO (Au, ∼15 nm), the photodegradation efficiency was enhanced and the photoreduction rate reduced compared to Au-ZnO. Pt-Au-ZnO hybrids showed better photodegradation and mineralization properties compared to both Au-ZnO and Au@Au-ZnO owing to a fast electron discharge (i.e. better electron-hole seperation). However, photoexcited electrons lacked the reducing power for the photoreduction of toluidine blue. The ultimate photodegradation efficiencies of Pt-Au-ZnO, Au@Au-ZnO, and Au-ZnO were 84, 66, and 39%, respectively. In the interest of effective metal-semiconductor type photocatalysts, the present study points out the importance of choosing the right metal, depending on whether a photoreduction and/or photodegradation process is desired.
Publisher: Elsevier BV
Date: 09-2020
Publisher: Springer Science and Business Media LLC
Date: 26-01-2018
DOI: 10.1038/S41467-017-02808-2
Abstract: Tin and its compounds hold promise for the development of high-capacity anode materials that could replace graphitic carbon used in current lithium-ion batteries. However, the introduced porosity in current electrode designs to buffer the volume changes of active materials during cycling does not afford high volumetric performance. Here, we show a strategy leveraging a sulfur sacrificial agent for controlled utility of void space in a tin oxide/graphene composite anode. In a typical synthesis using the capillary drying of graphene hydrogels, sulfur is employed with hard tin oxide nanoparticles inside the contraction hydrogels. The resultant graphene-caged tin oxide delivers an ultrahigh volumetric capacity of 2123 mAh cm –3 together with good cycling stability. Our results suggest not only a conversion-type composite anode that allows for good electrochemical characteristics, but also a general synthetic means to engineering the packing density of graphene nanosheets for high energy storage capabilities in small volumes.
Publisher: Wiley
Date: 30-09-2019
Abstract: In situ transmission electron microscopy (TEM) is one of the most powerful approaches for revealing physical and chemical process dynamics at atomic resolutions. The most recent developments for in situ TEM techniques are summarized in particular, how they enable visualization of various events, measure properties, and solve problems in the field of energy by revealing detailed mechanisms at the nanoscale. Related applications include rechargeable batteries such as Li-ion, Na-ion, Li-O
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4TA06303A
Abstract: A structure composed of a pseudocapacitive core (MoS 2 nanosheets) and an electrostatic double-layer capacitive porous shell (MOF-derived microporous carbons) was developed for advanced electrochemical energy storage.
Publisher: Wiley
Date: 13-09-2017
Abstract: In situ transmission electron microscopy (TEM) allows one to investigate nanostructures at high spatial resolution in response to external stimuli, such as heat, electrical current, mechanical force and light. This review exclusively focuses on the optical, optoelectronic and photocatalytic studies inside TEM. With the development of TEMs and specialized TEM holders that include in situ illumination and light collection optics, it is possible to perform optical spectroscopies and erse optoelectronic experiments inside TEM with simultaneous high resolution imaging of nanostructures. Optical TEM holders combining the capability of a scanning tunneling microscopy probe have enabled nanomaterial bending/stretching and electrical measurements in tandem with illumination. Hence, deep insights into the optoelectronic property versus true structure and its dynamics could be established at the nanometer-range precision thus evaluating the suitability of a nanostructure for advanced light driven technologies. This report highlights systems for in situ illumination of TEM s les and recent research work based on the relevant methods, including nanomaterial cathodoluminescence, photoluminescence, photocatalysis, photodeposition, photoconductivity and piezophototronics.
Publisher: American Chemical Society (ACS)
Date: 22-10-2018
DOI: 10.1021/ACS.NANOLETT.8B03398
Abstract: Research on electromechanical properties of semiconducting nanowires, including plastic behavior of Si nanowires and superb carrier mobility of Ge and Ge/Si core-shell nanowires, has attracted increasing attention. However, to date, there have been no direct experimental studies on crystallography dynamics and its relation to electrical and mechanical properties of Ge/Si core-shell nanowires. In this Letter, we in parallel investigated the crystallography changes and electrical and mechanical behaviors of Ge/Si core-shell nanowires under their deformation in a transmission electron microscope (TEM). The core-shell Ge/Si nanowires were bent and strained in tension to high limits. The nanowire Young's moduli were measured to be up to ∼191 GPa, and tensile strength was in a range of 3-8 GPa. Using high-resolution imaging, we confirmed that under large bending strains, Si shells had irregularly changed to the polycrystalline/amorphous state, whereas Ge cores kept single crystal status with the local lattice strains on the compressed side. The nanowires revealed cyclically changed electronic properties and had decent mechanical robustness. Electron diffraction patterns obtained from in situ TEM, paired with theoretical simulations, implied that nonequilibrium phases of polycrystalline/amorphous Si and β-Sn Ge appearing during the deformations may explain the regarded mechanical robustness and varying conductivities under straining. Finally, atomistic simulations of Ge/Si nanowires showed the pronounced changes in their electronic structure during bending and the appearance of a conductive channel in compressed regions which might also be responsible for the increased conductivity seen in bent nanowires.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TA04191B
Abstract: Vanadium( iii ) oxide (V 2 O 3 ) derived, carbon integrated hydrated vanadium oxide (V 5 O 12 ·0.4H 2 O) as an extrinsic pseudocapacitive material for excellent lithium storage in lithium ion battery anodes.
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4NR00963K
Abstract: CdS/ZnO branched heterostructures have been successfully synthesized by combining thermal vapour deposition and a hydrothermal method. Drastic optoelectronic performance enhancement of such heterostructures was revealed, compared to plain CdS nanobelts, as documented by comparative in situ optoelectronic studies on corresponding in idual nanostructures using an originally designed laser-compatible transmission electron microscopy (TEM) technique. Furthermore, flexible thin-film based photodetectors based on standard CdS nanobelts and newly prepared CdS/ZnO heterostructures were fabricated on PET substrates, and comparative photocurrent and photo-responsivity measurements thoroughly verified the in situ TEM results. The CdS/ZnO branched heterostructures were found to have better performance than standard CdS nanobelts for optoelectronic applications with respect to the photocurrent to dark current ratio and responsivity.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1JM14551G
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5TA08134C
Abstract: New boron nitride porous monoliths with high efficiency and excellent adsorption applications were successfully fabricated by a brand-new and template-free method.
Publisher: Wiley
Date: 14-07-2021
Abstract: The world is currently in the midst of a climate crises and many across the globe are competing to find new technologies to create clean, and effective ways of harnessing renewable energy sources. However, this energy needs to be stored and the current systems simply would not last. Zinc‐ion batteries (ZIBs) with vanadium‐containing cathodes are a recently arising technology providing a cheap, safe, and eco‐friendly alternative to the current systems. Vanadium is a material that has long been used for electrochemical systems due to its large range of stable oxidation states. Most common is the vanadium oxide (V 2 O 5 ) renowned for its open layered framework and manipulatable structure. However, this is not the only vanadium‐containing material that is proposed for use in ZIBs. The vanadium family is comprised of four main sub‐categories under which materials can be classified: vanadium oxides, vanadium phosphates, vanadates, and O 2 ‐free vanadium compounds. This report delves into the specifics of each of these sub‐families to further develop the understanding of their functionality by highlighting their structural and morphological characteristics, aptitude for modification, and the corresponding electrochemical properties. Through this investigation, the application of these materials in ZIB systems is highlighted and future development aims considered.
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7EE00329C
Abstract: The introduction of protrusions through P-doping into graphene is an effective strategy to enhance electrochemical performances in SIBs.
No related grants have been discovered for Chao Zhang.