ORCID Profile
0000-0002-5761-1860
Current Organisation
University of South Australia
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Biomaterials | Biomedical engineering | Cellular nervous system | Functional Materials | Materials Engineering | Metals and Alloy Materials | Composite and Hybrid Materials | Neural engineering
Expanding Knowledge in the Earth Sciences | Expanding Knowledge in the Physical Sciences | Expanding Knowledge in Engineering |
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6TA06746H
Abstract: Four different inorganic materials as electrode transport layers in fully roll-to-roll P3HT:ICxA organic solar cells were investigated.
Publisher: American Chemical Society (ACS)
Date: 12-10-2022
Abstract: Atomic-scale information about the structural and compositional properties of novel semiconductor nanowires is essential to tailoring their properties for specific applications, but characterization at this length scale remains a challenging task. Here, quasi-1D InAs/InGaAs semiconductor nanowire arrays were grown by selective area epitaxy (SAE) using molecular beam epitaxy (MBE), and their subsequent properties were analyzed by a combination of atom probe tomography (APT) and aberration-corrected transmission electron microscopy (TEM). Results revealed the chemical composition of the outermost thin InAs layer, a fine variation in the indium content at the InAs/InGaAs interface, and lightly incorporated element tracing. The results highlight the importance of correlative microscopy approaches in revealing complex nanoscale structures, with TEM being uniquely suited to interrogating the crystallography of InGaAs NWs, whereas APT is capable of three-dimensional (3D) elemental mapping, revealing the subtle compositional variation near the boundary region. This work demonstrates a detailed pathway for the nanoscale structural assessment of novel one-dimensional (1D) nanomaterials.
Publisher: Wiley
Date: 27-05-2021
Abstract: A new printable organic semiconducting material combination as a tissue equivalent photodetector for indirect X‐ray detection is demonstrated in this work. The device exhibits a higher optical‐to‐electrical conversion efficiency than any other reported printable organic systems for X‐ray photodetection while also operating efficiently with zero applied bias. Complete X‐ray detectors fabricated by coupling the photodiode with a plastic scintillator are among the first flexible and fully tissue equivalent X‐ray detectors capable of operating without external bias. The response to X‐rays is energy independent between 50 keV and 1.2 MeV, with a detection sensitivity equivalent to inorganic direct X‐ray detectors and one of the fastest temporal responses ever reported for organic X‐ray detectors. The materials can be printed into arrays with a pixel pitch of 120 μm, providing 2D spatial detection. The devices are found to be highly stable with respect to time, mechanical flexing, and large (5 kGy) radiation doses. The new materials and fully tissue equivalent X‐ray detectors reported here provide stable, printable, flexible, and tissue equivalent detectors with a high radiolucency that are ideally suited for wearable applications, where simultaneous monitoring and high transmission of the X‐ray absorbed dose into the human body is required.
Publisher: Frontiers Media SA
Date: 20-02-2017
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6TA04191D
Abstract: The synthesis and performance of a cost-effective mixed fullerene at the 100+ g scale with a reaction yield of 85% is demonstrated.
Publisher: Walter de Gruyter GmbH
Date: 12-2020
Abstract: Variation involving a switch between pre- and post-verbal placement of pronominal object clitics in a single syntactic environment within a language is unexpected. The rationale why this would not be expected is clear: Languages pattern as either proclitic or enclitic with respect to object clitic placement, possibly allowing one or the other option across different syntactic environments. We provide an overview of our research from data collected in Cyprus, related to the development and use of pronominal object clitics for child populations and adult speakers that are bilectal in Cypriot and Standard Modern Greek. While it has been shown that the tested bilectal populations receive exposure to more than one distinct grammar, including mixed grammars with optional choices for clitic placement, an important question remains unaddressed: Is variation really “free” across all speakers or are there universally reliable predictors (such as gender, age, or level of education) that mediate a consistent use of either the standard or the dialect? Combining insights from targeted elicitation tasks administered to different groups, a corpus of spontaneous speech, and an extensive literature review, we show the weakness of such purported predictors and support a claim of free variation.
Publisher: AIP Publishing
Date: 18-04-2011
DOI: 10.1063/1.3576904
Abstract: A remarkable 300% efficiency enhancement driven by a matching increase in the short circuit current was observed in a mixed porphyrin dye-sensitized solar cell constructed from two dyes in a 3:1 ratio. Absorbed photon-to-current conversion efficiency measurements indicate an improved charge injection yield for both dyes in the mixture. Several possible origins for the observed performance enhancement are discussed.
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0QM00980F
Abstract: This work unravels the intricate relationship between non-fullerene acceptor material surface energy and nanostructure formation in organic nanoparticle colloids.
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3CC47714B
Abstract: Asymmetric zinc phthalocyanines with alkyl chain substituents formed highly efficient light-harvesting layers on a TiO2 surface. Dye-sensitized solar cells using PcS20 exhibited a record efficiency of 6.4% under one-sun irradiation.
Publisher: American Chemical Society (ACS)
Date: 09-10-2009
DOI: 10.1021/JA9057713
Abstract: Zn-Zn porphyrin dimers have been incorporated into thin dye-sensitized solar cells (DSSCs) to boost their light harvesting efficiency. The photoexcited dimers show efficient and fast electron injection into TiO(2) indicating that both photoexcited chromophores contribute to current generation. The improved light harvesting ability coupled to enhanced DSSC performance demonstrates the potential of 3-D light harvesting arrays as next generation light harvesters for artificial solar energy conversion systems.
Publisher: American Chemical Society (ACS)
Date: 12-03-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9SE01149H
Abstract: A systematic approach for assessing organic photovoltaic (OPV) materials for large scale production based on the efficiency, lifetime and material cost has been developed. A Ω of 2.55 results in the following maximum material cost.
Publisher: Elsevier BV
Date: 02-2018
Publisher: American Chemical Society (ACS)
Date: 15-12-2011
DOI: 10.1021/JP107615H
Publisher: American Chemical Society (ACS)
Date: 03-08-2020
Publisher: American Chemical Society (ACS)
Date: 18-10-2011
DOI: 10.1021/JP2093109
Publisher: American Chemical Society (ACS)
Date: 20-07-2021
Abstract: The use of nanostructured materials for targeted and controlled delivery of bioactive molecules is an attractive alternative to conventional drug administration protocols, enabling selective targeting of diseased cells, lower administered dosages, and reduced systemic side effects. Although a variety of nanocarriers have been investigated in recent years, electroactive organic polymer nanoparticles present several exciting advantages. Here we demonstrate that thin films created from nanoparticles synthesized from violanthrone-79, an n-type semiconducting organic material, can incorporate and release dexamethasone
Publisher: Elsevier BV
Date: 05-2016
Publisher: Wiley
Date: 09-04-2013
Abstract: A series of zinc-phthalocyanine sensitizers (PcS16-18) with different adsorption sites have been designed and synthesized in order to investigate the dependence of adsorption-site structures on the solar-cell performances in zinc-phthalocyanine based dye-sensitized solar cells. The change of adsorption site affected the electron injection efficiency from the photoexcited dye into the nanocrystalline TiO2 semiconductor, as monitored by picosecond time-resolved fluorescence spectroscopy. The zinc-phthalocyanine sensitizer PcS18, possessing one carboxylic acid directly attached to the ZnPc ring and six 2,6-diisopropylphenoxy units, showed a record power conversion efficiency value of 5.9 % when used as a light-harvesting dye on a TiO2 electrode under one simulated solar condition.
Publisher: Frontiers Media SA
Date: 13-10-2017
Publisher: American Chemical Society (ACS)
Date: 17-09-2015
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4RA14247K
Abstract: In this study, binder-free TiO 2 colloidal pastes have been prepared using a variety of heterocyclic bases with erse characteristics to produce robust photoanodes for dye-sensitized solar cells (DSSC) from a single cast film thickness of 5 micron.
Publisher: Informa UK Limited
Date: 12-11-2017
Publisher: Springer Science and Business Media LLC
Date: 12-2020
DOI: 10.1557/MRC.2020.76
Publisher: American Chemical Society (ACS)
Date: 30-05-2013
DOI: 10.1021/JP3067712
Publisher: MDPI AG
Date: 30-04-2021
DOI: 10.3390/NANO11051185
Abstract: This work reports the development of a highly sensitive pressure detector prepared by inkjet printing of electroactive organic semiconducting materials. The pressure sensing is achieved by incorporating a quantum tunnelling composite material composed of graphite nanoparticles in a rubber matrix into the multilayer nanostructure of a printed organic thin film transistor. This printed device was able to convert shock wave inputs rapidly and reproducibly into an inherently lified electronic output signal. Variation of the organic ink material, solvents, and printing speeds were shown to modulate the multilayer nanostructure of the organic semiconducting and dielectric layers, enabling tuneable optimisation of the transistor response. The optimised printed device exhibits rapid switching from a non-conductive to a conductive state upon application of low pressures whilst operating at very low source-drain voltages (0–5 V), a feature that is often required in applications sensitive to stray electromagnetic signals but is not provided by conventional inorganic transistors and switches. The printed sensor also operates without the need for any gate voltage bias, further reducing the electronics required for operation. The printable low-voltage sensing and signalling system offers a route to simple low-cost assemblies for secure detection of stimuli in highly energetic systems including combustible or chemically sensitive materials.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2016
Publisher: American Chemical Society (ACS)
Date: 04-11-2013
DOI: 10.1021/AM403022D
Abstract: Dye sensitized solar cells (DSSCs) employing a dimer porphyrin, which was synthesised with two porphyrin units connected without conjugation, have shown that both porphyrin components can contribute to photocurrent generation, that is, more than 50 % internal quantum efficiency. In addition, the open-circuit voltage (Voc) of the DSSCs was higher than that of DSSCs using monomer porphyrins. In this paper, we first optimized cell structure and fabrication conditions. We obtained more than 80% incident photon to current conversion efficiency from the dimer porphyrin sensitized DSSCs and higher Voc and energy conversion efficiency than monomer porphyrin sensitized solar cells. To examine the origin of the higher Voc, we measured electron lifetime in the DSSCs with various conditions, and found that the dimer system increased the electron lifetime by improving the steric blocking effect of the dye layer, whilst the lack of a conjugated linker prevents an increase in the attractive force between conjugated sensitizers and the acceptor species in the electrolyte. The results support a hypothesis dispersion force is one of the factors influencing the electron lifetime in DSSCs.
Publisher: AIP Publishing
Date: 27-01-2014
DOI: 10.1063/1.4863216
Abstract: Nanoparticulate zinc oxide can be prepared at low temperatures from solution processable zinc acetylacetonate. The use of this material as a cathode interfacial layer in nanoparticulate organic photovoltaic devices results in comparable performances to those based on reactive calcium layers. Importantly, the enhanced degradation stability and full solution processability make zinc oxide a more desirable material for the fabrication of large area printed devices.
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4TA03226H
Abstract: Non-conjugated di-chromophoric zinc porphyrin dyads showed simultaneously improved V OC and J SC compared to the single zinc porphyrin.
Publisher: American Chemical Society (ACS)
Date: 29-09-2011
DOI: 10.1021/LA202598C
Abstract: The determination of the orientation and molecular density for several porphyrin dyes adsorbed on planar TiO(2) surfaces using X-ray reflectometry (XRR) is reported. Adsorption of nanoscale water layers occurred rapidly upon exposure of freshly prepared TiO(2) surfaces to ambient conditions however, this was successfully eliminated, resulting in clearly discernible adsorbed dye layers for sensitized surfaces. Adsorbed dye orientations, determined from computations constrained by the measured dye layer thickness, were calculated to have a binding tilt angle of 35°-40°. Combining the XXR data with the orientation models indicates that the porphyrins form densely packed surfaces with an intermolecular spacing of 3-4 Å, consistent with π-π stacking interactions. Changes in the molecular size of probe dyes were reflected in corresponding changes in the measured dye layer thickness, confirming the ability of this technique to resolve small variations in dye layer thickness and consequently adsorption orientation. Application of these results to understanding the behavior of dye-sensitized devices is discussed.
Publisher: American Chemical Society (ACS)
Date: 19-02-2019
Abstract: Deposition of functionalized nanoparticles onto solid surfaces has created a new revolution in electronic devices. Surface adsorbates such as ionic surfactants or additives are often used to stabilize such nanoparticle suspensions however, little is presently known about the influence of such surfactants and additives on specific electronic and chemical functionality of nanoparticulate electronic devices. This work combines experimental measurements and theoretical models to probe the role of an ionic surfactant in the fundamental physical chemistry and electronic charge carrier behavior of photodiode devices prepared using multicomponent organic electronic nanoparticles. A large capacitance was detected, which could be subsequently manipulated using the external stimuli of light, temperature, and electric fields. It was demonstrated that analyzing this capacitance through the framework of classical semiconductor analysis produced substantially misleading information on the electronic trap density of the nanoparticles. Electrochemical impedance measurements demonstrated that it is actually the stabilizing surfactant that creates capacitance through two distinct mechanisms, each of which influenced charge carrier behavior differently. The first mechanism involved a dipole layer created at the contact interfaces by mobile ions, a mechanism that could be replicated by addition of ions to solution-cast devices and was shown to be the major origin of restricted electronic performance. The second mechanism consisted of immobile ionic shells around in idual nanoparticles and was shown to have a minor impact on device performance as it could be removed upon addition of electronic charge in the photodiodes through either illumination or external bias. The results confirmed that the surfactant ions do not create a significantly increased level of charge carrier traps as has been previously suspected, but rather, preventing the diffusion of mobile ions through the nanoparticulate film and their accumulation at contacts is critical to optimize the performance.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2CC30677H
Abstract: Porphyrin molecules offer immense potential as the light harvesting component of dye-sensitised nanocrystalline TiO(2) solar cells. Synthetic porphyrin dyes were amongst the first dyes trialled for sensitisation of inorganic semiconducting oxides. Today, they exhibit the best performance reported for dye-sensitised solar cells. Accompanying the significant performance improvement over the last two decades is a much improved understanding of efficiency-determining fundamental electron transfer steps, from charge photogeneration to recombination. In this feature article we highlight our recent discoveries of the influence of porphyrin molecule structure on efficiency determining electron transfer kinetics and device performance by systematically changing the molecular structure and observing electron injection and recombination kinetics using time-resolved optical and electrical probes. Despite our observation of ultrafast charge injection for all porphyrin dyes studied by transient absorption spectroscopy, the injection yield estimated using an internal standard remains below 100% and depends strongly on the molecular structure. The observed discrepancy between kinetic competition and the injection yield is attributed to non-injecting dyes, probably arising due to inhomogeneity. A very interesting sub-ns (0.5 ns to 100 ns) charge recombination channel between photo-injected electrons and porphyrin cations is observed, which is found to be more prominent in free-base porphyrin dyes with a conjugated linker. Charge recombination between the acceptor species in the redox containing electrolyte and injected electrons is shown to be an important limitation of most porphyrin-sensitised solar cells, accelerated by the presence of porphyrin molecules at the TiO(2)-electrolyte interface. This recombination reaction is strongly dependent on the porphyrin molecular structure. Bulky substituents, using a porphyrin dimer instead of a porphyrin monomer, a light soaking treatment of freshly prepared films and co-sensitization of TiO(2) with multiple dyes are shown to be successful strategies to improve electron lifetime. Finally, new developments unique to porphyrin dye-sensitised solar cells, including performance enhancements from a light exposure treatment of a zinc porphyrin dye, a significant performance improvement observed after co-sensitisation of TiO(2) with free-base and zinc porphyrin dyes and the use of porphyrin dimers with increased light harvesting in thin-film TiO(2) solar cells are described.
Publisher: AIP Publishing
Date: 06-10-2014
DOI: 10.1063/1.4897140
Abstract: Here, we report the development of an organic thin film transistor (OTFT) based on printable solution processed polymers and employing a quantum tunnelling composite material as a sensor to convert the pressure wave output from detonation transmission tubing (shock tube) into an inherently lified electronic signal for explosives initiation. The organic electronic detector allows detection of the signal in a low voltage operating range, an essential feature for sites employing live ordinances that is not provided by conventional electronic devices. We show that a 30-fold change in detector response is possible using the presented detector assembly. Degradation of the OTFT response with both time and repeated voltage scans was characterised, and device lifetime is shown to be consistent with the requirements for on-site printing and usage. The integration of a low cost organic electronic detector with inexpensive shock tube transmission fuse presents attractive avenues for the development of cheap and simple assemblies for precisely timed initiation of explosive chains.
Publisher: Springer Science and Business Media LLC
Date: 20-09-2019
DOI: 10.1557/MRC.2019.132
Publisher: IOP Publishing
Date: 10-12-2019
Abstract: Printed electronics is simultaneously one of the most intensely studied emerging research areas in science and technology and one of the fastest growing commercial markets in the world today. For the past decade the potential for organic electronic (OE) materials to revolutionize this printed electronics space has been widely promoted. Such conviction in the potential of these carbon-based semiconducting materials arises from their ability to be dissolved in solution, and thus the exciting possibility of simply printing a range of multifunctional devices onto flexible substrates at high speeds for very low cost using standard roll-to-roll printing techniques. However, the transition from promising laboratory innovations to large scale prototypes requires precise control of nanoscale material and device structure across large areas during printing fabrication. Maintaining this nanoscale material control during printing presents a significant new challenge that demands the coupling of OE materials and devices with clever nanoscience fabrication approaches that are adapted to the limited thermodynamic levers available. In this review we present an update on the strategies and capabilities that are required in order to manipulate the nanoscale structure of large area printed organic photovoltaic (OPV), transistor and bioelectronics devices in order to control their device functionality. This discussion covers a range of efforts to manipulate the electroactive ink materials and their nanostructured assembly into devices, and also device processing strategies to tune the nanoscale material properties and assembly routes through printing fabrication. The review finishes by highlighting progress in printed OE devices that provide a feedback loop between laboratory nanoscience innovations and their feasibility in adapting to large scale printing fabrication. The ability to control material properties on the nanoscale whilst simultaneously printing functional devices on the square metre scale is prompting innovative developments in the targeted nanoscience required for OPV, transistor and biofunctional devices.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2021
Publisher: Beilstein Institut
Date: 20-02-2018
DOI: 10.3762/BJNANO.9.60
Abstract: In this study we have optimised the preparation conditions for large-volume nanoparticle inks, based on poly(3-hexylthiophene) (P3HT):indene-C 60 multiadducts (ICxA), through two purification processes: centrifugal and crossflow ultrafiltration. The impact of purification is twofold: firstly, removal of excess sodium dodecyl sulfate (SDS) surfactant from the ink and, secondly, concentration of the photoactive components in the ink. The removal of SDS was studied in detail both by a UV–vis spectroscopy-based method and by surface tension measurements of the nanoparticle ink filtrate revealing that centrifugal ultrafiltration removed SDS at a higher rate than crossflow ultrafiltration even though a similar filter was applied in both cases (10,000 Da M w cut-off). The influence of SDS concentration on the aqueous solar nanoparticle (ASNP) inks was investigated by monitoring the surface morphology/topography of the ASNP films using atomic force microscopy (AFM) and scanning electron microscopy (SEM) and photovoltaic device performance as a function of ultrafiltration (decreasing SDS content). The surface morphology/topography showed, as expected, a decreased number of SDS crystallites on the surface of the ASNP film with increased ultrafiltration steps. The device performance revealed distinct peaks in efficiency with ultrafiltration: centrifuge purified inks reached a maximum efficiency at a dilution factor of 7.8 × 10 4 , while crossflow purified inks did not reach a maximum efficiency until a dilution factor of 6.1 × 10 9 . This difference was ascribed to the different wetting properties of the prepared inks and was further corroborated by surface tension measurements of the ASNP inks which revealed that the peak efficiencies for both methods occurred for similar surface tension values of 48.1 and 48.8 mN m −1 . This work demonstrates that addressing the surface tension of large-volume ASNP inks is key to the reproducible fabrication of nanoparticle photovoltaic devices.
Publisher: American Chemical Society (ACS)
Date: 15-03-2016
Abstract: This work investigates the detection and subsequent utilization of leaked light from bends in a silica optical fiber using organic photovoltaic detectors. The optic power lost by single mode and multimode silica optical fibers was calibrated for bend radii between 1 and 7 mm for 532 and 633 nm light, exhibiting excellent agreement with previous theoretical solutions. The spatial location of maximum power leakage on the exterior of the fiber was found to exist in the same plane as the fiber, with a 10° offset from the normal. Two different organic photovoltaic detectors fabricated using a poly(3-hexylthiophene):indene-C60-bisadduct donor-acceptor blend cast from chloroform and chlorobenzene were fabricated to detect the leaked light. The two detectors exhibited different photovoltaic performances, predominantly due to different active layer thicknesses. Both devices showed sensitivity to leakage light, exhibiting voltages between 200 and 300 mV in response to leaked light from the fiber. The temporal responses of the devices were observed to differ, with a rise time from 10% to 90% of maximum voltage of 1430 μs for the chlorobenzene device, and a corresponding rise time of 490 μs for the higher performing chloroform device. The two OPVs were used to simultaneously detect leaked light from induced bends in the optical fiber, with the differing temporal profiles employed to create a unique time-correlated detection signal with enhanced security. The delay between detection of each OPV voltage could be systematically varied, allowing for either a programmable and secure single detection signal or triggering of multiple events with variable time resolution. The results reported in this study present exciting avenues toward the deployment of this simple and noninvasive optical detection system in a range of different applications.
Publisher: American Chemical Society (ACS)
Date: 22-11-2021
Start Date: 02-2023
End Date: 01-2026
Amount: $463,985.00
Funder: Australian Research Council
View Funded ActivityStart Date: 04-2024
End Date: 04-2028
Amount: $843,325.00
Funder: Australian Research Council
View Funded ActivityStart Date: 12-2022
End Date: 04-2024
Amount: $2,020,000.00
Funder: Australian Research Council
View Funded Activity