Publications
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Journal articles
Earp, A.A., Franklin, J.B. & Smith, G.B.2011, 'Absorption tails and extinction in luminescent solar concentrators', Solar Energy Materials And Solar Cells, vol. 95, no. 4, pp. 1157-1162.
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Non-ultraviolet (UV) photoexposure of luminescent solar concentrators (LSC's) can produce photoproducts that cause additional extinction at wavelengths somewhat longer than the main dye absorption peak. This photo-induced 'tails' extinction is deleterious to luminous output in collectors of useful lengths. An experimental method that enables the subdivision of tails extinction in an LSC into absorbed and scattered components is described. The relevant theory is outlined, and experimental results are presented for a polymethyl methacrylate (PMMA) LSC containing Lumogen F083 dye. For this sample, tails absorption increased significantly with outdoor exposure, while tails scattering remained constant. Further measurements indicate that LSC luminous output is around five times more sensitive to tails absorption than to fluorescence quenching. This work also indicates that merely checking for dye quenching, as is often done, can be a misleading indicator of long-term LSC output.
Roest, R., Latella, B., Heness, G.L. & Ben-Nissan, B.2011, 'Adhesion of sol-gel derived hydroxyapatite nanocoatings on anodised pure titanium and titanium (Ti6Al4V) alloy substrates', Surface & Coatings Technology, vol. 205, no. 11, pp. 3520-3529.
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The mechanical properties and adhesion behaviour of sol-gel derived hydroxyapatite (HA) nanocoatings on commercially pure (cp) titanium (Ti) and Ti6Al4V alloy have been determined and related to anodising treatment. The surface roughness, wetting and coating characteristics were examined using profilometry, contact angle, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Nano-indentation was used to determine the Young's modulus and hardness of the coatings, while microtensile tests were used to introduce controlled strains in the coatings through the cp Ti and TiAl6V4 alloy substrates, from which the strength, fracture toughness and adhesion behaviour could be ascertained based on multiple cracking and delamination events. The toughness of the HA coatings is found to be slightly lower to that of equivalent bulk pure HA ceramics. The substrate and the anodized layer thickness have the most influence on the interfacial adhesion of HA, with nanocoatings on Ti6Al4V exhibiting superior interfacial bonding in comparison to cp Ti.
Jiang, L., Fan, G., Li, Z., Chen, Z., Zhang, D., Kai, X., Humphries, S.R., Heness, G.L. & Yeung, W.Y.2011, 'An approach to the uniform dispersion of a high volume fraction of carbon nanotubes in aluminum powder', Carbon, vol. 49, no. 6, pp. 1965-1971.
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A slurry based process was developed to achieve the uniform dispersion of a high volume fraction of carbon nanotubes (CNTs) in aluminum powder. Al powder was subjected to surface modification to introduce a hydrophilic polyvinyl alcohol (PVA) membrane on its surface, which has good wettability and strong hydrogen bonding interactivity with functionalized CNTs. It was found that, when mixed with a CNT aqueous suspension, the PVA-modified Al (Al@PVA) powder resulted in much better adsorption uniformity of CNTs than the untreated Al powder. The adsorption capacity of CNTs was greatly enhanced by using nanoflake Al powder, which has better geometric compatibility with the CNTs and a larger surface area than spherical powder. Consequently, a uniform dispersion of 20 vol.% CNTs was achieved in the nanoflake Al@PVA powders. The advantage of this approach is that it provides easy control over adsorption uniformity and capacity of CNTs in a metal matrix, through the combination of surface modification and thickness adjustment of the metal flake powders.
Moezzi Azari, A.M., Cortie, M.B. & McDonagh, A.M.2011, 'Aqueous pathways for the formation of zinc oxide nanoparticles', Dalton Transactions, vol. 40, no. 18, pp. 4871-4878.
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We examine the effect of reactant concentrations, temperatures and feeding methods on the morphology of ZnO formed when reacting solutions of ZnSO4 and NaOH. The catalytic effect of hydroxide in excess relative to the stoichiometric ratio is considered. It is shown that, having fixed other reaction conditions, the end-products, particle structures and size strongly depend on the mole ratio of the precursors. The presence of zinc salt hydroxide species was confirmed at sub-stoichiometric ratios in slightly acidic conditions. At the stoichiometric ratio both zinc hydroxide and zinc oxide are formed, while only zinc oxide forms in an excess of hydroxide. The method of feeding the reactants into the reaction vessel also has a strong influence on the end-product properties, as does the reaction temperature. By control of these parameters the specific surface area could be varied from 10 to 33 m2 g-1, the particle shape could be varied from equiaxed, through to star-like and needle-like, and the particle size may be varied from 50 to over 300 nm.
Wagner, M.R., Callsen, G.J., Reparaz, J., Schulze, J., Kirste, R., Cobet, M., Ostapenko, I., Rodt, S., Nenstiel, C., Kaiser, M., Hoffmann, A.V., Rodina, A., Phillips, M.R., Lautenschlager, S., Eisermann, S. & Meyer, B.K.2011, 'Bound Excitons In Zno: Structural Defect Complexes Versus Shallow Impurity Centers', Physical Review B, vol. 84, no. 3, pp. 0-0.
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ZnO single crystals, epilayers, and nanostructures often exhibit a variety of narrow emission lines in the spectral range between 3.33 and 3.35 eV which are commonly attributed to deeply bound excitons (Y lines). In this work, we present a comprehensive
Porkovich, A., Arnold, M.D., Kouzmina, G., Hingley, B., Dowd, A.R. & Cortie, M.B.2011, 'Calorimetric sensor for use in hydrogen peroxide aqueous solutions', Sensor Letters, vol. 9, no. 2, pp. 695-697.
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A sensor for characterising aqueous solutions of hydrogen peroxide is described. The sensor is based on the calorimetric signal obtained when catalysing the decomposition of H(2)O(2). The system is quick and simple, and is suitable for determinations of H(2)O(2) concentration between 0% and at least 50% (w/w).
Lem, L.L., Ton-That, C. & Phillips, M.R.2011, 'Distribution of visible luminescence centers in hydrogen-doped ZnO', Journal of Materials Research, vol. 26, no. 23, pp. 2912-2915.
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ZnO crystals have been investigated by scanning cathodoluminescence microscopy and spectroscopy at 80 K following hydrogen incorporation by plasma exposure. The intensity of the ZnO near-band-edge ( NBE) emission is greatly enhanced while the defect-related green emission is quenched following plasma treatment. These effects are attributed to the passivation of zinc vacancies by hydrogen. The green and yellow intensities and their intensity ratios to the NBE vary with excitation depth for both undoped and H-doped ZnO crystals. The intensities of the green and yellow emissions exhibit sublinear dependencies on electron beam excitation density while the NBE intensity increases linearly with the excitation density. These saturation effects with increasing excitation density must be taken into account when assessing defects in ZnO by luminescence characterization.
Earp, A.A. & Smith, G.B.2011, 'Evolution of plasmonic response in growing silver thin films with pre-percolation non-local conduction and emittance drop', Journal of Physics D: Applied Physics, vol. 44, p. 255102.
Austin, C.E., Fryer, F.I., Lear, J., Bishop, D.P., Hare, D.J., Rawling, T., Kirkup, L., McDonagh, A.M. & Doble, P.A.2011, 'Factors Affecting Internal Standard Selection For Quantitative Elemental Bio-Imaging Of Soft Tissues By La-Icp-Ms', Journal Of Analytical Atomic Spectrometry, vol. 26, no. 7, pp. 1494-1501.
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Element response variations under different laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) operating conditions were investigated to identify important factors for selecting an internal standard (IS) for quantitative elemental bi
Cortie, M.B., Kealley, C.S., Bhatia, V.K., Thorogood, G., Elcombe, M. & Avdeev, M.2011, 'High Temperature Transformations Of The Au(7)Cu(5)Al(4) Shape-Memory Alloy', Journal Of Alloys And Compounds, vol. 509, no. 8, pp. 3502-3508.
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The beta-phase of Au(7)Cu(5)Al(4) undergoes a reversible shape-memory phase transformation, however there has been some uncertainty regarding the crystal structure or structures of the parent phase. Here we show that, under equilibrium conditions, the pa
Zou, J., Le Rendu, P., Musa, I., Yang, S., Dan, Y., Ton-That, C. & Nguyen, T.2011, 'Investigation of the optical properties of polyfluorene/ZnO nanocomposites', Thin Solid Films, vol. 519, pp. 3997-4003.
Steven, R., Toth, M., Cullen, J., Chandler, O. & Lobo, C.2011, 'Kinetics of gas mediated electron beam induced etching', Applied Physics Letters, vol. 99, no. 21, pp. 213103-213105.
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Electron beam induced etching (EBIE) is a high resolution, direct write, chemical dry etch process in which surface-adsorbed precursor molecules are activated by an electron beam. We show that nanoscale EBIE is rate limited through at least two mechanisms ascribed to adsorbate depletion and the transport of gaseous precursor molecules into an etch pit during etching, respectively. The latter has, to date, not been accounted for in models of EBIE and is needed to reproduce etch kinetics which govern the time-evolution of etch pits, EBIE throughput, and spatial resolution.
Chaysuwan, D., Sirinukunwattana, K., Kanchanatawewat, K., Heness, G.L. & Yamashita, K.2011, 'Machinable glass-ceramics forming as a restorative dental material', Dental Materials Journal, vol. 30, no. 3, pp. 358-367.
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MgO, SiO(2), Al(2)O(3), MgF(2), CaF(2), CaCO(3), SrCO(3), and P(2)O(5) were used to prepare glass-ceramics for restorative dental materials. Thermal properties, phases, microstructures and hardness were characterized by DTA, XRD, SEM and Vickers microhar
Bhatia, V.K., Kealley, C.S., Prior, M.J. & Cortie, M.B.2011, 'Martensite Destabilization In Au(7)Cu(5)Al(4) Shape-Memory Alloy', Acta Materialia, vol. 59, no. 5, pp. 2193-2200.
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Aging-induced changes in the austenite peak (A(P)) temperature of Au(7)Cu(5)Al(4) shape-memory alloy are investigated. Whereas heat treating the parent phase at temperatures >140 degrees C or aging the martensite for long times at room temperature both s
Gentle, A.R., Aguilar, J.L. & Smith, G.B.2011, 'Optimized cool roofs: Integrating albedo and thermal emittance with R-value', Solar Energy Materials And Solar Cells, vol. 95, no. 12, pp. 3207-3215.
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For cool roofs the combined effect of the three parameters that define heat gain and loss from a roof, namely solar albedo a, thermal emittance E, and sub-roof R-value, must be considered. An accurate contribution of night sky cooling, and hence humidity and total down-welling atmospheric radiation is needed. A systematic analysis of the contribution of a roof to average cooling load per day and to peak load reductions is presented for a temperate climate zone over 6 cooling months using an hour-by-hour analysis. Eighteen 3-parameter sets (a,E,R) demonstrate the over-riding importance of a high a, while sensitivity to R-value and E drops away as albedo rises. Up-front cost per unit reductions in peak demand or average energy use per day always rises strongly as R rises unless albedo is low. A moderate R similar to 1.63 is superior to high R unless a roof is dark, or winter heating demand is high. We indicate briefly why the roof typically does not present a dominant influence on average winter heating needs in most temperate zones, enhancing the benefits of cool roofs.
Callsen, G.J., Reparaz, J., Wagner, M.R., Kirste, R., Nenstiel, C., Hoffmann, A.V. & Phillips, M.R.2011, 'Phonon Deformation Potentials In Wurtzite Gan And Zno Determined By Uniaxial Pressure Dependent Raman Measurements', Applied Physics Letters, vol. 98, no. 6, pp. 1-3.
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We report the phonon deformation potentials of wurtzite GaN and ZnO for all zone center optical phonon modes determined by Raman measurements as a function of uniaxial pressure. Despite all the structural and optical similarities between these two materi
Kirkup, L. & Bonfiglioli, C.M.2011, 'Research-inspired Learning Revitalises The Curriculum For First-year Science Majors', International Journal of Science and Mathematics Education, vol. 19, no. 1, pp. 1-15.
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We describe a curriculum innovation designed and implemented by a multidisciplinary team that engages first-year students in large enrolment subjects in science research and improves their writing. We have devised an activity for science majors that conn
Cortie, M.B. & McDonagh, A.M.2011, 'Synthesis and optical properties of hybrid and alloy plasmonic nanoparticles', Chemical Reviews, vol. 111, no. 6, pp. 3713-3735.
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The plasmon resonances and other optical properties of elemental noble and alkali metal nanoparticles have generated enormous scienti?c interest. 1-11 There are numerous applications for plasmon-active nanoparticles, especially in areas such as biological microscopy, medicine, and sensors. 12-18 The various applications exploit some aspect of the plasmon resonance, which include particle-particle plasmon interactions, 19 the unusual coloring or dichroic e?ects in isolated particles, 20,21 light-induced plasmonic heating, 22 light scattering, 23 or twophoton phenomena. 24 Hybrid or multifunctional nanoparticles constructed from more than one component phase have also been attracting increasing interest due to their additional functionalities. 25-30 In this review, we consider speci?cally the optical properties of solid nanoparticles composed of more than one phase or compound. Alloyed nanoparticles (solid solutions or intermetallic compounds of the metallic elements) are also included because these intergrade with the two-phase hybrids
Chou, J., Ben-Nissan, B., Green, D.D., Valenzuela, S. & Kohan, L.2011, 'Targeting And Dissolution Characteristics Of Bone Forming And Antibacterial Drugs By Harnessing The Structure Of Microspherical Shells From Coral Beach Sand', Advanced Engineering Materials, vol. 13, no. 1-2, pp. 93-99.
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Pharmaceutical drugs for the treatment of metabolic bone diseases lead to a number of side effects due to the their uncontrollable dispersion throughout the body.([1]) Therefore, many groups directed their research to develop devices that are targeted to
Pissuwan, D., Niidome, T. & Cortie, M.B.2011, 'The forthcoming applications of gold nanoparticles in drug and gene delivery systems', Journal of Controlled Release, vol. 149, pp. 65-71.
Keast, V.J., Birt, K., Koch, C., Supansomboon, S. & Cortie, M.B.2011, 'The role of plasmons and interband transitions in the color of AuAl2 AuIn2 AuGa2', Applied Physics Letters, vol. 99, no. 11, pp. 111908-1-111908-3.
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First principles calculations of the optical properties of the intermetallic compounds AuAl2, AuIn2, and AuGa2 have been performed. Analysis of the dielectric functions showed that AuAl2 is unique because a bulk plasmon is seen in the optical region and contributes to the purple color of this material. An experimental electron energy-loss spectrum showed excellent agreement with the theoretical prediction and confirmed the presence of the bulk plasmon.
Cortie, M.B., Xiao, L.H., Erdei, L., Kealley, C.S., Dowd, A.R., Kimpton, J.A. & McDonagh, A.M.2011, 'Thermal Stability of (KxNayH1-x-y)2Ti6O13 Nanofibers', European Journal Of Inorganic Chemistry, vol. 2011, no. 33, pp. 5087-5095.
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Potassium-rich titanate nanofibers were produced by digesting TiO2 in concentrated KOH solutions under hydrothermal conditions. The nanofibers were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and thermogravimetric analysis. A hexatitanate structure was assigned, in contrast to the trititanate structure usually resulting from NaOH treatment of TiO2. The potassium cations could be exchanged with others, such as sodium, hydrogen, and ammonium. The potassium-rich hexatitanate was found to be photocatalytic in its as-synthesized condition. The thermal stability of the fibers during calcination was followed in situ using X-ray diffraction and was found to be strongly dependent on the chemical composition. The potassium-rich titanate converted to anatase at only 480 ?C, whereas the hydrogen- and ammonium-rich materials had to be heated to over 600 ?C before conversion took place. Conversion was notably slowest in the ammonium-rich material. Surprisingly, the sodium-rich hexatitanate did not form anatase at temperatures up to 800 ?C and instead recrystallized.
Callsen, G.J., Reparaz, J., Wagner, M.R., Vierck, A., Phillips, M.R., Thomsen, C. & Hoffmann, A.V.2011, 'Titanium-assisted growth of silica nanowires: from surface-matched to free-standing morphologies', Nanotechnology, vol. 22, no. 40, p. 405604.
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We report on an oxide-assisted growth technique for silica nanowires which allows tuning the growth from surface-matched nanowires to free-standing morphologies based on growth control by Ti in the role of a catalyst and surfactant. Using an adjustable Ti concentration, we grew silica nanowires with lengths ranging from 100 nm up to several millimetres whose defect chemistry was analysed by electron microscopy tools, monochromatic cathodoluminescence imaging and time resolved photoluminescence spectroscopy. The knowledge of the luminescence properties and the related defect occurrence along with their spatial distribution is pivotal for advancing silica nanowire growth in order to realize successful device designs based on self-assembled Si/SiO(x) nanostructures. We demonstrate a core-shell structure of the grown nanowires with a highly luminescent 150 nm thick shell and outstandingly fast decaying dynamics (approximate to 1 ns) for glass-like materials. The conjunction of the observed efficient and stable luminescences with their attributed decaying behaviours suggests applications for silica nanowires such as active and passive optical interconnectors and white light phosphors. The identification of a time domain difference for the spectral regime from 2.3 to 3.3 eV, within the confined spatial dimensions of a single nanowire, is very promising for future, e. g. data transmission applications, employing silica nanowires which exhibit achievable compatibility with commonly applied silicon-based electronics. A qualitative growth model based on silica particle diffusion and Ti-assisted seed formation is developed for the various types of segregated silica nanowires which extends commonly assumed oxide-assisted growth mechanisms.
Lin, Z., Li, Y., Zhu, J., Wang, X., Dou, S.X., Guo, Y., Lei, G., Wang, Y., Phillips, M.R., Cortie, M.B., Li, Y., Choi, K. & Shi, X.2011, 'Visualization Of Vortex Motion In Feas-Based Bafe(1.9)Ni(0.1)As(2) Single Crystal By Means Of Magneto-Optical Imaging', Journal Of Applied Physics, vol. 109, no. 7, pp. 0-0.
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Superconductivity has been found in newly discovered iron-based compounds. This paper studies the motion of magnetic vortices in BaFe(1.9)Ni(0.1)As(2) single crystal by means of the magneto-optical imaging technique. A series of magneto-optical images re
Conference papers
Gentle, A.R. & Smith, G.B. 2011, 'Performance comparisons of sky window spectral selective and high emittance radiant cooling systems under varying atmospheric conditions', Canberra, Australia, December 2010 in Solar 2010 : Proceedings of the 48th AuSES Annual Conference, ed Igor Skryabin, Australian Solar Energy Society, Australia.
Smith, G.B., Gentle, A.R., Edmonds, I. 2011, 'Urban growth, albedo and global warming', Canberra, December 2010 in Solar 2010 : Proceedings of the 48th AuSES Annual Conference, ed Igor Skryabin, Australian Solar Energy Society, Australia.
