ORCID Profile
0000-0001-9942-8637
Current Organisations
The University of Auckland
,
University of New South Wales
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Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1NR10765H
Abstract: Tailoring the density of random single-walled carbon nanotube (SWCNT) networks is of paramount importance for various applications, yet it remains a major challenge due to the insufficient catalyst activation in most growth processes. Here we report on a simple and effective method to maximise the number of active catalyst nanoparticles using catalytic chemical vapor deposition (CCVD). By modulating short pulses of acetylene into a methane-based CCVD growth process, the density of SWCNTs is dramatically increased by up to three orders of magnitude without increasing the catalyst density and degrading the nanotube quality. In the framework of a vapor-liquid-solid model, we attribute the enhanced growth to the high dissociation rate of acetylene at high temperatures at the nucleation stage, which can be effective in both supersaturating the larger catalyst nanoparticles and overcoming the nanotube nucleation energy barrier of the smaller catalyst nanoparticles. These results are highly relevant to numerous applications of random SWCNT networks in next-generation energy, sensing and biomedical devices.
Publisher: InTech
Date: 09-05-2013
DOI: 10.5772/52674
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9TC01808E
Abstract: A direct one-step nano-gold printing process from a HAuCl 4 solution precursor is demonstrated using an atmospheric-pressure plasma jet.
Publisher: Elsevier BV
Date: 2021
Publisher: Springer Science and Business Media LLC
Date: 12-08-2014
Abstract: Control over nucleation and growth of multi-walled carbon nanotubes in the nanochannels of porous alumina membranes by several combinations of posttreatments, namely exposing the membrane top surface to atmospheric plasma jet and application of standard S1813 photoresist as an additional carbon precursor, is demonstrated. The nanotubes grown after plasma treatment nucleated inside the channels and did not form fibrous mats on the surface. Thus, the nanotube growth mode can be controlled by surface treatment and application of additional precursor, and complex nanotube-based structures can be produced for various applications. A plausible mechanism of nanotube nucleation and growth in the channels is proposed, based on the estimated depth of ion flux penetration into the channels. PACS 63.22.Np Layered systems 68. Surfaces and interfaces Thin films and nanosystems (structure and non-electronic properties) 81.07.-b Nanoscale materials and structures: fabrication and characterization
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2012
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7NR09309H
Abstract: Titanium nitride is an emerging plasmonic material active in the visible and NIR region. In this work, we provide detailed analysis to correlate their optical properties with their morphology and surface composition.
Publisher: American Chemical Society (ACS)
Date: 19-02-2015
DOI: 10.1021/SC500806S
Publisher: Wiley
Date: 07-03-2014
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8TA11646F
Abstract: WO 3 /graphene composite minimizes the polysulfide dissolution problem in the lithium–sulfur (Li–S) battery systems while exhibiting an excellent battery performance.
Publisher: Springer Science and Business Media LLC
Date: 02-05-2016
Publisher: IOP Publishing
Date: 14-04-2011
DOI: 10.1088/0022-3727/44/17/174019
Abstract: The fast advances in nanotechnology have raised increasing concerns related to the safety of nanomaterials when exposed to humans, animals and the environment. However, despite several years of research, the nanomaterials safety field is still in its infancy owing to the complexities of structural and surface properties of these nanomaterials and organism-specific responses to them. Recently, plasma-based technology has been demonstrated as a versatile and effective way for nanofabrication, yet its health and environment-benign nature has not been widely recognized. Here we address the environmental and occupational health and safety effects of various zero- and one-dimensional nanomaterials and elaborate the advantages of using plasmas as a safe nanofabrication tool. These advantages include but are not limited to the production of substrate-bound nanomaterials, the isolation of humans from harmful nanomaterials, and the effective reforming of toxic and flammable gases. It is concluded that plasma nanofabrication can minimize the hazards in the workplace and represents a safe way for future nanofabrication technologies.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4RA08187K
Abstract: Vertically-aligned carbon nanotube arrays treated with inductively-coupled plasmas demonstrate selective support of biofilms of Gram-negative and Gram-positive bacteria.
Publisher: Wiley
Date: 14-05-2014
Abstract: Graphene and carbon nanotubes (CNTs) are attractive electrode materials for supercapacitors. However, challenges such as the substrate-limited growth of CNTs, nanotube bundling in liquid electrolytes, under-utilized basal planes, and stacking of graphene sheets have so far impeded their widespread application. Here we present a hybrid structure formed by the direct growth of CNTs onto vertical graphene nanosheets (VGNS). VGNS are fabricated by a green plasma-assisted method to break down and reconstruct a natural precursor into an ordered graphitic structure. The synergistic combination of CNTs and VGNS overcomes the challenges intrinsic to both materials. The resulting VGNS/CNTs hybrids show a high specific capacitance with good cycling stability. The charge storage is based mainly on the non-Faradaic mechanism. In addition, a series of optimization experiments were conducted to reveal the critical factors that are required to achieve the demonstrated high supercapacitor performance.
Publisher: Elsevier BV
Date: 03-2017
DOI: 10.1016/J.BIOS.2016.04.072
Abstract: Here, we present a rapid, low-temperature (200°C) plasma-enabled synthesis of graphene micro-islands (GMs). Morphological analyses of GMs by scanning electron microscopy (SEM) and atomic force microscopy (AFM) feature a uniform and open-networked array of aggregated graphene sheets. Structural and surface chemical characterizations by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) support the presence of thin graphitic edges and reactive oxygen functional groups. We demonstrate that these inherent properties of GMs enable its multifunctional capabilities as a bioactive interface. GMs exhibit a biocompatibility of 80% cell viability with primary fibroblast lung cells after 5 days. Further, GMs were assembled into an impedimetric genosensor, and its performance was characterized by electrochemical impedance spectroscopy (EIS). A dynamic sensing range of 1pM to 1nM is reported, and a limit of quantification (LOQ) of 2.03×10
Publisher: American Chemical Society (ACS)
Date: 17-01-2019
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8SE00022K
Abstract: This work showcases the application of crystal and facet engineering combined with techniques to provide insights into the development of materials for solar energy conversion.
Publisher: World Scientific Pub Co Pte Lt
Date: 12-2011
DOI: 10.1142/S1793604711002330
Abstract: Al -doped zinc oxide (AZO) thin films are deposited onto glass substrates using radio-frequency reactive magnetron sputtering and the improvements in their physical properties by post-synthesis thermal treatment are reported. X-ray diffraction spectra show that the structure of films can be controlled by adjusting the annealing temperatures, with the best crystallinity obtained at 400°C under a nitrogen atmosphere. These films exhibit improved quality and better optical transmittance as indicated by the UV-Vis spectra. Furthermore, the sheet resistivity is found to decrease from 1.87 × 10 -3 to 5.63 × 10 -4 Ω⋅cm and the carrier mobility increases from 6.47 to 13.43 cm 2 ⋅ V -1 ⋅ s -1 at the optimal annealing temperature. Our results demonstrate a simple yet effective way in controlling the structural, optical and electrical properties of AZO thin films, which is important for solar cell applications.
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CC00282A
Abstract: An atmospheric microplasma jet produces three-dimensional (3D) microfluidic channels on dense arrays of vertically aligned carbon nanotubes, which confines Au nanodot aqueous solution. The resulting hybrid 3D nanostructure is exploited as an effective microscopic area-selective sensing platform based on surface-enhanced Raman scattering.
Publisher: Springer Science and Business Media LLC
Date: 10-2014
DOI: 10.1038/AM.2014.100
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CC00282A
Abstract: An atmospheric microplasma jet produces three-dimensional (3D) microfluidic channels on dense arrays of vertically aligned carbon nanotubes, which confines Au nanodot aqueous solution. The resulting hybrid 3D nanostructure is exploited as an effective microscopic area-selective sensing platform based on surface-enhanced Raman scattering.
Publisher: Elsevier BV
Date: 12-2013
Publisher: American Physical Society (APS)
Date: 10-06-2022
Publisher: American Scientific Publishers
Date: 12-2015
Abstract: Mankind faces several global challenges such as chronic and acute hunger, global poverty, energy deficiency and environment conservation. Common biotechnologies based on batch, fluidbed and other similar processes are now extensively used for the production of a wide range of products such as antibiotics, biofuels, cultured and fermented food products. Unfortunately, these processes suffer from low efficiency, high energy demand, low controllability and rapid biocatalyst degradation by microbiological attack, and thus still are not capable of seriously addressing the global hunger and energy deficiency challenges. Moreover, sustainable future technologies require minimizing the environmental impact of toxic by-products by implementing the "life produces organic matter, organic matter sustains life" principle. Nanostructure-based biotechnology is one of the most promising approaches that can help to solve these challenges. In this work we briefly review the unique features of the carbon-based nanostructured platforms, with some attention paid to other nanomaterials. We discuss the main building blocks and processes to design and fabricate novel platforms, with a focus on dense arrays of the vertically-aligned nanostructures, mainly carbon nanotubes and graphene. Advantages and disadvantages of these systems are considered.
Publisher: Wiley
Date: 12-11-2019
Publisher: Wiley
Date: 23-07-2023
Abstract: Orthopedic implants provide patients with an opportunity to regain functionality lost from illness, disease, or injury. Recent advancements in additive manufacturing (AM) techniques have allowed for the increased customization of Ti‐6Al‐4V ELI (extra low interstitials) implants to complement natural variations in the human anatomy. Yet, the low bioactivity of Ti‐6Al‐4 V ELI and possible adverse effects from the leeching of aluminum and vanadium complicate the post‐operation recovery process. In this work, Ti‐6Al‐4 V ELI s les are printed using the electron beam melt technique in two directions and coated with diamond‐like carbon (DLC) to examine whether their biological properties can be improved. By conducting in vitro studies with Saos‐2 osteosarcoma cells, the effects of morphology and surface chemistry are correlated to the bioactivities of the coated and uncoated s les. The outcome of the study suggested that DLC coating is a viable method for controlling the surface bioactivity of a material. It indicates that a carbon coating, along with an appropriate topography, has the potential to promote the proliferation and maturity of bone cells and hence enhance the performance of additively manufactured products in next‐generation biomedical applications.
Publisher: AIP Publishing
Date: 10-06-2013
DOI: 10.1063/1.4811165
Abstract: Palladium is sputtered on multi-walled carbon nanotube forests to form carbon-metal core-shell nanowire arrays. These hybrid nanostructures exhibited resistive responses when exposed to hydrogen with an excellent baseline recovery at room temperature. The magnitude of the response is shown to be tuneable by an applied voltage. Unlike the charge-transfer mechanism commonly attributed to Pd nanoparticle-decorated carbon nanotubes, this demonstrates that the hydrogen response mechanism of the multi-walled carbon nanotube-Pd core-shell nanostructure is due to the increase in electron scattering induced by physisorption of hydrogen. These hybrid core-shell nanostructures are promising for gas detection in hydrogen storage applications.
Publisher: Elsevier BV
Date: 09-2015
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4GC02135E
Abstract: Vertical graphene nanosheets (VGS) transformed from honeycomb are used for high-performance supercapacitors and selective detection of amyloid-beta (Aβ) species.
Publisher: Elsevier BV
Date: 04-2020
Publisher: AIP Publishing
Date: 11-2011
DOI: 10.1063/1.3657842
Abstract: A simple and effective method of controlling the growth of vertically aligned carbon nanotube arrays in a low-temperature plasma is presented. Ni catalyst was pretreated by plasma immersion ion implantation prior to the nanotube growth by plasma-enhanced chemical vapor deposition. Both the size distribution and the areal density of the catalyst nanoparticles decrease due to the ion-surface interactions. Consequently, the resulting size distribution of the vertically aligned carbon nanotubes is reduced to 50 ∼ 100 nm and the areal density is lowered (by a factor of ten) to 108 cm−2, which is significantly different from the very-high-density carbon nanotube forests commonly produced by thermal chemical vapor deposition. The efficiency of this pretreatment is compared with the existing techniques such as neutral gas annealing and plasma etching. These results are highly relevant to the development of the next-generation nanoelectronic and optoelectronic devices that require effective control of the density of nanotube arrays.
No related grants have been discovered for Samuel Yick.