BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Probing Film Morphology and Surface Microstructure of Semiconducti ng Polymers with GIWAXS and NEXAFS DTSTART;VALUE=DATE-TIME:20141120T032000Z DTEND;VALUE=DATE-TIME:20141120T034000Z DTSTAMP;VALUE=DATE-TIME:20260719T192632Z UID:indico-contribution-203-771@events01.synchrotron.org.au DESCRIPTION:Speakers: Masrur Morshed Nahid (Monash University)\nIn making organic electronics a reality\, donor-acceptor based semiconducting polyme rs will play a pivotal role. The molecular packing\, orientation and cryst allinity of semiconducting polymer thin-films strongly influence the perfo rmance of organic electronic devices. Grazing Incidence Wide-Angle X-ray S cattering (GIWAXS) collected at the SAXS/WAXS beamline has been used to pr obe the molecular packing and relative crystallinity of polymer thin films \; while Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy a t the soft X-ray beamline has been used to probe the microstructure and mo lecular orientation of film-surfaces. A novel polymer BFS4 is studied\, which is based on a dithienyl-benzo[1\,2-b’:4\,5-b’]dithiophene as a d onor-unit and 5-fluoro-2\,1\,3-benzothiadiazole as an acceptor-unit. GIWAX S reveals that the crystallites are in a mixture of orientations where the in-plane alkyl-chain stacking distance is 2.17 ± 0.01 nm and out-of-plan e π-stacking distance is 0.385 ± 0.005 nm. Coherence lengths are measure d to be 15 ± 2 nm and 2.6 ± 0.2 nm respectively. Two different types of solution processing methods show differing crystallinity\, which can be co rrelated directly to their respective transistor charge transport properti es. NEXAFS reveals a mixture of edge-on and face-on orientations of the mo lecular planes\, and the same orientational preference is confirmed. NEXAF S additionally reveals the relative orientation of the donor and acceptor units of the backbone of this novel polymer\, probing backbone planarity d irectly.\n\nhttps://events01.synchrotron.org.au/event/3/contributions/771/ LOCATION: NCSS Seminar Room URL:https://events01.synchrotron.org.au/event/3/contributions/771/ END:VEVENT BEGIN:VEVENT SUMMARY:Morphological investigations of naphthalene diimide derivatives DTSTART;VALUE=DATE-TIME:20141120T030000Z DTEND;VALUE=DATE-TIME:20141120T032000Z DTSTAMP;VALUE=DATE-TIME:20260719T192632Z UID:indico-contribution-203-711@events01.synchrotron.org.au DESCRIPTION:Speakers: Adam Welford (Monash University)\nSolution-cast\, or ganic field-effect transistors (OFET) have many advantages\, such as rapid \, large area fabrication\, low production cost and flexible substrates ma king them ideal for specialized application such as flexible displays and radio frequency identification.\nThe small molecule organic semiconductor (OSC) naphthalene diimide (NDI) provides a versatile framework with which to build upon and explore the effects of chemical functionalisation. \nOve r the past year\, we have utilized two complimentary synchrotron based tec hniques to examine the effect on structure and morphology as the basic NDI framework is functionalised. \nAt the soft x-ray beamline\, Near Edge X-r ay Absorption Fine Structure (NEXAFS) spectroscopy allowed us to explore t he surface molecular orientation and electronic changes. Expansion of the NDI core was found to give higher average tilt angles with core-expanded d erivatives also maintaining their high average tilt angle when annealed. \ nAt the SAXS/WAXS beamline these same materials were investigated using Gr azing Incidence Wide Angle X-ray Scattering (GIWAXS) to assess crystallini ty and molecular packing. The data confirms both the highly edge on packin g behaviour of the core expanded set and the drastic change to the molecul ar unit cell upon NDI core expansion.The π – π stacking distance of th e conjugated cores\, which is an important element of transistor design to allow effective charge transfer\, is also measured for each of the materi als. \nThis information will aid and inform the ongoing design of our NDI molecules as we progress towards a high mobility\, air stable OFET.\n\nhtt ps://events01.synchrotron.org.au/event/3/contributions/711/ LOCATION: URL:https://events01.synchrotron.org.au/event/3/contributions/711/ END:VEVENT BEGIN:VEVENT SUMMARY:Characterisation of scale products formed on the heat-exchanger su rfaces in the Bayer process DTSTART;VALUE=DATE-TIME:20141120T034000Z DTEND;VALUE=DATE-TIME:20141120T040000Z DTSTAMP;VALUE=DATE-TIME:20260719T192632Z UID:indico-contribution-203-680@events01.synchrotron.org.au DESCRIPTION:Speakers: Lina Shi (University of South Australia)\nVast quant ities of bauxite ore\, used for the production of alumina (Al2O3) via the Bayer process\, contain appreciable concentrations of reactive silicates. Secondary precipitation of these silicates within Bayer plants results in deleterious scale formation consisting largely of aluminosilicate and tita nate phases\, with resulting losses of caustic soda and decreased heat tra nsfer efficiency. In spite of numerous related laboratory studies\, an ins ufficient amount of data has been published regarding the characterisation of these industrial scales\, which can provide vital information pertaini ng to the mechanism of scale growth. SEM\, XRD and EDS analyses were carri ed out on selected scale samples removed from the inside wall of plant equ ipment across a number of alumina refineries. SEM images of the cross-sect ion of the industrial scale samples were carried out to explore compositio nal changes with depth from the wall. High amorphous content of the indust rial samples were calculated using XRD Rietveld analysis and the addition of corundum was used as an internal standard. Therefore\, XANES at both t he Al and Si K-edges was applied to identify the amorphous phases\, in con junction with XRD and EDS results\, which were demonstrated to consist pre dominantly of poorly crystallised sodalite. There is strong correlation be tween the amorphous content and the scale microstructure. High amorphous c ontent appears to indicate nucleation of the scale occurred on the interna l surfaces of the heat exchangers. Low amorphous content suggest the desil ication product particles form in the slurry during desilication and then deposit on the heat exchange surfaces.\n\nhttps://events01.synchrotron.org .au/event/3/contributions/680/ LOCATION: NCSS Seminar Room URL:https://events01.synchrotron.org.au/event/3/contributions/680/ END:VEVENT BEGIN:VEVENT SUMMARY:Stability and Surface Reconstruction of Bi2Se3 on Exposure to Atmo sphere DTSTART;VALUE=DATE-TIME:20141120T023000Z DTEND;VALUE=DATE-TIME:20141120T030000Z DTSTAMP;VALUE=DATE-TIME:20260719T192632Z UID:indico-contribution-203-647@events01.synchrotron.org.au DESCRIPTION:Speakers: Mark Edmonds (Monash University)\nThe new class of t opological materials including Bi2Se3 offer opportunities to develop next generation electron devices that utilize spin generation and detection wit hout ferromagnetism [1]. However\, the fate of the Bi2Se3 surface upon exp osure to atmosphere remains unclear. In particular whilst the topology of Bi2Se3 guarantees the presence of a metallic surface\, the topological pro perties of the metallic surface depend on the surface and its reconstructi on [2]. Therefore\, it is essential to understand the structure of the air -exposed Bi2Se3 surface in order to interpret the properties of any air-ex posed Bi2Se3 device. \n\nUtilizing high-resolution surface sensitive XPS w e reveal that five minute air exposure causes a drastic change to the surf ace of in-situ cleaved Bi2Se3. An additional component within the Bi 5d co re level was observed after exposure that corresponds to the formation of isolated ~0.8 nm thick Bi2 layers at the surface of Bi2Se3 [3]. This Bi2 l ayer is found to occur across multiple samples and is precipitated rapidly by exposure to atmosphere\, while samples left for several days in UHV af ter in-situ cleaving show no change. This finding offers new avenues to st udy a 2D TI (Bi2) interfaced with a 3D TI (Bi2Se3) but also has significan t consequences in understanding the electronic structure of air-exposed Bi 2Se3. \n\n\n[1] Y. Xia\, et al.\, Nature Physics 5\, 398 (2009).\n[2] Q. D . Gibson\, et al.\, Phys. Rev. B 88\, 081108(R) (2013).\n[3] M. T. Edmonds \, et al.\, J. Phys. Chem. C 118\, 20413 (2014).\n\nhttps://events01.synch rotron.org.au/event/3/contributions/647/ LOCATION: URL:https://events01.synchrotron.org.au/event/3/contributions/647/ END:VEVENT END:VCALENDAR