A comparative study on the role of polyvinylpyrrolidone molecular weight on the functionalization of various carbon nanotubes and their composites

Polyvinylidene fluoride (PVDF) nanocomposites filled with polyvinylpyrrolidone (PVP) wrapped carbon nanotubes were prepared via a solution casting technique. The effect of the molecular weight (polymer chain length) of the PVP on the ability to wrap different nanotube structures and its impact towards nanotube dispersibility in the polymer matrix was explored. The study was conducted with PVP of four different molecular weights and nanotubes of three different structures. The composites that exhibit an effective nanotube dispersion lead to a nanotube network that facilitates improved thermal, electrical, and mechanical properties. It was observed that nanotubes of different structures exhibit stable dispersions in the polymer matrix though PVP functionalization of different molecular weights, but the key is achieving an effective nanotube dispersion at low PVP concentrations. This is observed in MWNT and AP-SWNT based composites with PVP of low molecular weight, leading to a thermal conductivity enhancement of 147% and 53%, respectively, while for P3-SWNT based composites, PVP of high molecular weight yields an enhancement of 25% in thermal conductivity compared to the non-functionalized CNT-PVDF composite. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Plasmonic Gold Nanostars Incorporated into High-Efficiency Perovskite Solar Cells

Incorporating appropriate plasmonic nanostructures into photovoltaic (PV) systems is of great utility for enhancing photon absorption and thus improving device performance. Herein, the successful integration of plasmonic gold nanostars (AuNSs) into mesoporous TiO2 photoelectrodes for perovskite solar cells (PSCs) is reported. The PSCs fabricated with TiO2-AuNSs photoelectrodes exhibited a device efficiency of up to 17.72 %, whereas the control cells without AuNSs showed a maximum efficiency of 15.19 %. We attribute the origin of increased device performance to enhanced light absorption and suppressed charge recombination

Jury decision making: a systematic review and exploration of stigma towards offenders with mental health conditions and the impact of diagnostic labels.

Aims: This thesis portfolio focuses on public stigma towards offenders with mental health conditions within legal settings. Method: A systematic review was conducted focusing on the factors that influence stigma towards offenders with mental health conditions and what the consequences of this can be. The empirical paper focuses how different diagnostic labels may influence mental health stigma and juror decision making within a mock homicide trial. By conducting a replication of Baker et al., (2022), the paper compares public stigma towards two different diagnostic labels (psychopathy and personality disorder) and a control label (complex mental health condition) to further build this area of limited literature. Findings: Seventeen studies were included within the systematic review. Factors found to influence stigma included diagnostic labels, traits, political orientation and religious beliefs. The consequences of this stigma were harsher punishment recommendations and higher likelihood of rejecting the insanity pleas of defendants. The empirical paper found no evidence that diagnostic labels influence stigmatic attitudes, causal attributes or Diminished Responsibility decision making. Perceived personal controllability of the situation was found to be a significant predictor of participants’ decisions regarding Diminished Responsibility. Conclusions: Public stigma towards offenders with mental health conditions can be influenced by a variety of factors, with significant life changing consequences within legal settings. Both clinical and legal professionals must consider the way in which information about a mental health condition is presented within a court as this may impact decision making. The limitations, implications and recommendations for future research are discussed further

Preparation of carbon surfaces for sensing applications via plasma hydrogenation

[Canberra, ACT

Solution processed graphene–silicon Schottky junction solar cells

Here, surfactant-assisted exfoliated graphene (SAEG) has been used to make transparent conducting graphene films which for the first time were used to make SAEG–silicon Schottky junctions for photovoltaics. The graphene films were characterised using UV-Vis spectroscopy, Raman spectroscopy, atomic force microscopy and four point probe sheet resistance measurements. The effects of film thickness, thermal annealing and chemical doping of the graphene films on the power conversion efficiency (PCE) of the cells were investigated. Mild annealing of thickness optimised films resulted in a doubling of the PCE. Additionally, chemical doping resulted in a further 300% increase of the peak PCE. These results indicate that SAEG has the potential to compete with chemical vapour deposited graphene in graphene–silicon Schottky junction applications.This work was supported by the Australian Microscopy and Microanalysis Research Facility (AMMRF). This work was also performed in part at the Flinders University node of the Australian National Fabrication Facility, a company established under the National Collaborative Research Infrastructure Strategy to provide nano- and micro-fabrication facilities for Australia's researchers

Transition from single to multi-walled carbon nanotubes grown by inductively coupled plasma enhanced chemical vapor deposition

In this work a simple and up-scalable technique for creating arrays of high purity carbon nanotubes via plasma enhanced chemical vapor deposition is demonstrated. Inductively coupled plasma enhanced chemical vapor deposition was used with methane and argon mixtures to grow arrays in a repeatable and controllable way. Changing the growth conditions such as temperature and growth time led to a transition between single and multi-walled carbon nanotubes and was investigated. This transition from single to multi-walled carbon nanotubes is attributed to a decrease in catalytic activity with time due to amorphous carbon deposition combined with a higher susceptibility of single-walled nanotubes to plasma etching. Patterning of these arrays was achieved by physical masking during the iron catalyst deposition process. The low growth pressure of 100 mTorr and lack of reducing gas such as ammonia or hydrogen or alumina supporting layer further show this to be a simple yet versatile procedure. These arrays were then characterized using scanning electron microscopy, Raman spectroscopy and x-ray photoelectron spectroscopy. It was also observed that at high temperature (550 °C) single-walled nanotube growth was preferential while lower temperatures (450 °C) produced mainly multi-walled arrays

Preparation of catalytic substrates with ordered size of iron nanoparticles for production carbon nanotubes

Canberra, ACT, Australi

Has the expansion in extended criteria deceased donors led to a different type of delayed graft function and poorer outcomes?

Objectives: There has been considerable change in the practice of deceased kidney transplantation in the past 15 years, with more extreme phenotypes implanted. The aim of this study was to determine whether increased use of expanded criteria donors (extended criteria donors and donors after circulatory death) affected clinical outcomes, including the incidence and pattern of delayed graft function. Methods and materials: A retrospective analysis of 1359 renal transplants was performed over 15 years. The first 10 years of data (group 1) were compared with the subsequent 5 years (group 2). Outcomes were analyzed at 6 months and 12 months in addition to serum creatinine and patterns of delayed graft function (posttransplant times: on hemodialysis, to peak creatinine, for creatinine to half, and for creatinine to fall within 10% of baseline). Results: There was a significant increase in the percentage of expanded criteria donor allografts used in group 2 with a significant increase in the incidence of delayed graft function. Despite this, serum creatinine and the incidence of biopsy-proven acute rejection had both improved in group 2. Group 2 expanded criteria donor kidneys had a significantly lower incidence of type 1 delayed graft function and a significantly higher incidence of types 3 and 4 delayed graft function. Time for creatinine to half in both groups was the best predictor of a serum creatinine <180 μmol/L at 1 year. Conclusion: The increased use of expanded criteria donor kidneys has led to a higher incidence of delayed graft function, but the pattern has shown that the requirement for hemodialysis has significantly reduced

Combined thermal and FTIR analysis of porous silicon based nano-energetic films

Nanoporous silicon (pSi) films on a silicon wafer were loaded with sodium perchlorate (SP) and perfluoropolyether (PFPE) oxidising agents to generate a pyrotechnic energetic material. The potentially violent reaction between the silicon and the loaded oxidising agent was studied using correlated differential scanning calorimetry (DSC) and FTIR spectroscopy for samples heated continuously between ambient and 500 degrees C. We observed that the energetic reaction between pSi and SP depended on the presence of various hydride species on the surface of freshly etched pSi, and on formation of volatile free radical species released during either oxidation of the surface in the presence of air at about 200 degrees C or during desorption of the hydride above 270 degrees C in the absence of oxygen. However, energetic reactions between pSi and PFPE were delayed until pyrolysis of the PFPE above 390 degrees C in the absence of oxygen, suggesting PFPE's suitability for pyrotechnics applications. Correlated thermal and spectroscopic methods of analysis gave new insights into the earliest stages of the reaction of these energetic materials

Characterisation of Methane Plasma Treated Carbon Surfaces

Los Alamitos, US