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Juodkazis S.,Melbourne Center For Nanofabrication
International Journal of Nanomedicine | Year: 2012

The laser polymerization capabilities of biocompatible and cross-linkable materials using direct laser writing are discussed. Purpose: Cross-disciplinary highlight of synergy between medical applications and laser microfabrication. © 2012 Juodkazis, publisher and licensee Dove Medical Press Ltd. Source

Altissimo M.,Melbourne Center For Nanofabrication
Biomicrofluidics | Year: 2010

Electron beam lithography (EBL) is one of the tools of choice for writing micro- and nanostructures on a wide variety of materials. This is largely due to the fact that modern EBL machines are capable of writing nanometer-sized structures on areas up to mm 2. The aim of this contribution is to give technical and practical backgrounds in this extremely flexible nanofabrication technique. © 2010 American Institute of Physics. Source

Davis T.J.,CSIRO | Davis T.J.,Melbourne Center For Nanofabrication | Hendry E.,University of Exeter
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

We show theoretically that localized surface plasmons can generate optical fields with a chirality exceeding that of circularly polarized light by a factor of 50. This superchiral optical field can be formed from linearly polarized light incident on nonchiral metal structures. We identify three mechanisms that lead to large optical chirality involving the coupling between the incident light and the evanescent fields of the surface plasmons. Two of these mechanisms create superchiral regions with nonzero average chirality suitable for the excitation of chiral molecules in solution. © 2013 American Physical Society. Source

Cappel U.B.,Monash University | Cappel U.B.,Imperial College London | Daeneke T.,Monash University | Bach U.,Monash University | And 2 more authors.
Nano Letters | Year: 2012

Solid state dye-sensitized solar cells (sDSCs) employing the hole conductor 2,2′7,7′-tetrakis-(N,N-di-p-methoxyphenyl-amine)-9,9′- spirobifluorene (spiro-MeOTAD) require the presence of oxygen during fabrication and storage. In this paper, we determine the concentrations of oxidized spiro-MeOTAD within devices under different operating and storage conditions by UV-vis spectroscopy. Relative concentrations of spiro-MeOTAD + were found to be greater than 10% after illumination for standard sDSCs, where no chemical dopant had been used in the solar cell fabrication but oxygen and lithium ions were present. We suggest that oxidized spiro-MeOTAD is created as a byproduct of oxygen reduction at the TiO 2 surface during cell illumination. Furthermore, we studied the effect of light soaking under different conditions and associated changes in spiro-MeOTAD + concentration on the solar cell measurements. Our findings give insights to photochemical reactions occurring within sDSCs and provide guidelines for which doping levels should be used in device fabrication in absence of oxygen. © 2012 American Chemical Society. Source

Dentry M.B.,Monash University | Yeo L.Y.,RMIT University | Friend J.R.,Melbourne Center For Nanofabrication
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2014

Acoustic streaming underpins an exciting range of fluid manipulation phenomena of rapidly growing significance in microfluidics, where the streaming often assumes the form of a steady, laminar jet emanating from the device surface, driven by the attenuation of acoustic energy within the beam of sound propagating through the liquid. The frequencies used to drive such phenomena are often chosen ad hoc to accommodate fabrication and material issues. In this work, we seek a better understanding of the effects of sound frequency and power on acoustic streaming. We present and, using surface acoustic waves, experimentally verify a laminar jet model that is based on the turbulent jet model of Lighthill, which is appropriate for acoustic streaming seen at micro-to nanoscales, between 20 and 936 MHz and over a broad range of input power. Our model eliminates the critically problematic acoustic source singularity present in Lighthill's model, replacing it with a finite emission area and enabling determination of the streaming velocity close to the source. At high acoustic power P (and hence high jet Reynolds numbers ReJ associated with fast streaming), the laminar jet model predicts a one-half power dependence (U∼P1/2∼ ReJ) similar to the turbulent jet model. However, the laminar model may also be applied to jets produced at low powers-and hence low jet Reynolds numbers ReJ-where a linear relationship between the beam power and streaming velocity exists: U∼P∼ReJ2. The ability of the laminar jet model to predict the acoustic streaming behavior across a broad range of frequencies and power provides a useful tool in the analysis of microfluidics devices, explaining peculiar observations made by several researchers in the literature. In particular, by elucidating the effects of frequency on the scale of acoustically driven flows, we show that the choice of frequency is a vitally important consideration in the design of small-scale devices employing acoustic streaming for microfluidics. © 2014 American Physical Society. Source

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