Hybrid CuTCNQ/AgTCNQ metal-organic charge transfer complexes via galvanic replacement vs. corrosion recrystallization

This study reports a hybrid of two metal-organic semiconductors that are based on organic charge transfer complexes of 7,7,8,8-tetracyanoquinodimethane (TCNQ). It is shown that the spontaneous reaction between semiconducting microrods of CuTCNQ with Ag+ ions leads to the formation of a CuTCNQ/AgTCNQ hybrid, both in aqueous solution and acetonitrile, albeit with completely different reaction mechanisms. In an aqueous environment, the reaction proceeds by a complex galvanic replacement (GR) mechanism, wherein in addition to AgTCNQ nanowires, Ag0 nanoparticles and Cu(OH)2 crystals decorate the surface of CuTCNQ microrods. Conversely, in acetonitrile, a GR mechanism is found to be thermodynamically unfavorable and instead a corrosion-recrystallization mechanism leads to the decoration of CuTCNQ microrods with AgTCNQ nanoplates, resulting in a pure CuTCNQ/AgTCNQ hybrid metal-organic charge transfer complex. While hybrids of two different inorganic semiconductors are regularly reported, this report pioneers the formation of a hybrid involving two metal-organic semiconductors that will expand the scope of TCNQ-based charge transfer complexes for improved catalysis, sensing, electronics and biological applications.

Adsorption and mobility of metals in build-up on road surfaces

The study investigated the adsorption and bioavailability characteristics of traffic generated metals common to urban land uses, in road deposited solids particles. To validate the outcomes derived from the analysis of field samples, adsorption and desorption experiments were undertaken. The analysis of field samples revealed that metals are selectively adsorbed to different charge sites on solids. Zinc, copper, lead and nickel are adsorbed preferentially to oxides of manganese, iron and aluminium. Lead is adsorbed to organic matter through chemisorption. Cadmium and chromium form weak bonding through cation exchange with most of the particle sizes. Adsorption and desorption experiments revealed that at high metal concentrations, chromium, copper and lead form relatively strong bonds with solids particles while zinc is adsorbed through cation exchange with high likelihood of being released back into solution. Outcomes from this study provide specific guidance for the removal of metals from stormwater based on solids removal.

Pt(II) bipyridyl complexes bearing substituted fluorenyl motif on the bipyridyl and acetylide ligands : synthesis, photophysics, and reverse saturable absorption

A series of Pt(II) diimine complexes bearing benzothiazolylfluorenyl (BTZ-F8), diphenylaminofluorenyl (NPh2- F8), or naphthalimidylfluorenyl (NI-F8) motifs on the bipyridyl or acetylide ligands (Pt-4−Pt-8), (i.e., {4,4′-bis[7-R1-F8-(≡)n-]bpy}Pt(7- R2-F8- ≡ -)2, where F8 = 9,9′-di(2-ethylhexyl)fluorene, bpy = 2,2′- bipyridine, Pt-4: R1 = R2 = BTZ, n = 0; Pt-5: R1 = BTZ, R2 = NI, n = 0; Pt-6: R1 = R2 = BTZ, n = 1; Pt-7: R1 = BTZ, R2 = NPh2, n = 1; Pt- 8: R1 = NPh2, R2 = BTZ, n = 1) were synthesized. Their ground-state and excited-state properties and reverse saturable absorption performances were systematically investigated. The influence of these motifs on the photophysics of the complexes was investigated by spectroscopic methods and simulated by time-dependent density functional theory (TDDFT). The intense absorption bands below 410 nm for these complexes is assigned to predominantly 1π,π* transitions localized on either the bipyridine or the acetylide ligands; while the broad low-energy absorption bands between 420 and 575 nm are attributed to essentially 1MLCT (metal-to-ligand charge transfer)/ 1LLCT (ligand-to-ligand charge transfer) transitions, likely mixed with some 1ILCT (intraligand charge transfer) transition for Pt-4−Pt-7, and predominantly 1ILCT transition admixing with minor 1MLCT/1LLCT characters for Pt-8. The different substituents on the acetylide and bipyridyl ligands, and the degrees of π-conjugation in the bipyridyl ligand influence both the 1π,π* and charge transfer transitions pronouncedly. All complexes are emissive at room temperature. Upon excitation at their respective absorption band maxima, Pt-4, Pt-6, and Pt-8 exhibit acetylide ligand localized 1π,π* fluorescence and 3MLCT/3LLCT phosphorescence in CH2Cl2, while Pt-5 manifests 1ILCT fluorescence and 3ILCT phosphorescence. However, only 1LLCT fluorescence was observed for Pt-7 at room temperature. The nanosecond transient absorption study was carried out for Pt-4−Pt-8 in CH3CN. Except for Pt-7 that contains NPh2 at the acetylide ligands, Pt-4−Pt-6 and Pt-8 all exhibit weak to moderate excited-state absorption in the visible spectral region. Reverse saturable absorption (RSA) of these complexes was demonstrated at 532 nm using 4.1 ns laser pulses in a 2 mm cuvette. The strength of RSA follows this trend: Pt-4 > Pt-5 > Pt-7 > Pt-6 > Pt-8. Incorporation of electron-donating substituent NPh2 on the bipyridyl ligand significantly decreases the RSA, while shorter π-conjugation in the bipyridyl ligand increases the RSA. Therefore, the substituent at either the acetylide ligands or the bipyridyl ligand could affect the singlet and triplet excited-state characteristics significantly, which strongly influences the RSA efficiency.

Time-independent charge carrier mobility in a model polymer:fullerene organic solar cell

The technique of photo-CELIV (charge extraction by linearly increasing voltage) is one of the more straightforward and popular approaches to measure the faster carrier mobility in measurement geometries that are relevant for operational solar cells and other optoelectronic devices. It has been used to demonstrate a time-dependent photocarrier mobility in pristine polymers, attributed to energetic relaxation within the density of states. Conversely, in solar cell blends, the presence or absence of such energetic relaxation on transport timescales remains under debate. We developed a complete numerical model and performed photo-CELIV experiments on the model high efficiency organic solar cell blend poly[3,6-dithiophene-2-yl-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-naphthalene] (PDPP-TNT):[6,6]-phenyl-C71-butyric-acid-methyl-ester (PC70BM). In the studied solar cells a constant, time-independent mobility on the scale relevant to charge extraction was observed, where thermalisation of photocarriers occurs on time scales much shorter than the transit time. Therefore, photocarrier relaxation effects are insignificant for charge transport in these efficient photovoltaic devices.

Charge mediated semiconducting-to-metallic phase transition in molybdenum disulphide monolayer and hydrogen evolution reaction in New 1T’ phase

The phase transition of single layer molybdenum disulphide (MoS2) from semi-conducting 2H to metallic 1T and then to 1T' phases, and the effect of the phase transition on hydrogen evolution reaction (HER) are investigated within this work by density functional theory. Experimentally, 2H-MoS2 has been widely used as an excellent electrode for HER and can get charged easily. Here we find that the negative charge has a significant impact on the structural phase transition in a MoS2 monolayer. The thermodynamic stability of 1T-MoS2 increases with the negative charge state, comparing with the 2H-MoS2 structure before phase transition and the kinetic energy barrier for a phase transition from 2H to 1T decreases from 1.59 eV to 0.27 eV when 4 e- are injected per MoS2 unit. Additionally, 1T phase is found to transform into the distorted structure (1T' phase) spontaneously. On their activity toward hydrogen evolution reaction, 1T'-MoS2 structure hydrogen coverage shows comparable hydrogen evolution reaction activity to the 2H-MoS2 structure. If the charge transfer kinetics is taken into account, the catalytic activity of 1T'-MoS2 is superior to that of 2H-MoS2. Our finding provides a possible novel method for phase transition of MoS2, and enriches understanding of the catalytic properties of MoS2 for HER.

Charge mediated semiconducting-to-metallic phase transition in molybdenum disulfide monolayer and hydrogen evolution reaction in new 1T′ phase

The phase transition of single layer molybdenum disulfide (MoS2) from semiconducting 2H to metallic 1T and then to 1T′ phases, and the effect of the phase transition on hydrogen evolution reaction (HER) are investigated within this work by density functional theory. Experimentally, 2H-MoS2 has been widely used as an excellent electrode for HER and can get charged easily. Here we find that the negative charge has a significant impact on the structural phase transition in a MoS2 monolayer. The thermodynamic stability of 1T-MoS2 increases with the negative charge state, comparing with the 2H-MoS2 structure before phase transition and the kinetic energy barrier for a phase transition from 2H to 1T decreases from 1.59 to 0.27 eV when 4e– are injected per MoS2 unit. Additionally, 1T phase is found to transform into the distorted structure (1T′ phase) spontaneously. On their activity toward hydrogen evolution reaction, 1T′-MoS2 structure shows comparable hydrogen evolution reaction activity to the 2H-MoS2 structure. If the charge transfer kinetics is taken into account, the catalytic activity of 1T′-MoS2 is superior to that of 2H-MoS2. Our finding provides a possible novel method for phase transition of MoS2 and enriches understanding of the catalytic properties of MoS2 for HER.

The influence of small amounts of N2 in SF6 on prebreakdown discharges

Pre-breakdown discharge activity in SF6 and SF6 +2% N2 at 1 bar absolute has been investigated to assess the feasibility of adding small amounts of N2 to SF6 to improve the luminosity of the pre-breakdown discharges. It has been shown that small amounts of N2 does not significantly alter the breakdown strength of the mixture but will have a profound influence on the pre-breakdown discharge activity under 50 Hz voltages and lightning impulse voltages. This influence is attributed to the following three mechanisms: 1. The increased availability of free electrons due to the lower ionisation potential of the N2 compared to SF6 2. The removal of high energy electrons from the discharge by electron scattering due to negative ion resonance in N2, thus effectively increasing the attachment of SF6. 3. The creation of longer lived SF6- ions by the attachment of the scattered low energy electrons from N2 thus effectively enhancing the negative ion space charge.

An efficient hole transport material composite based on poly(3-hexylthiophene) and bamboo-structured carbon nanotubes for high performance perovskite solar cells

In this work, we have developed a new efficient hole transport material (HTM) composite based on poly(3- hexylthiophene) (P3HT) and bamboo-structured carbon nanotubes (BCNs) for CH3NH3PbI3 (MAPbI3) based perovskite solar cells. Compared to pristine P3HT, it is found that the crystallinity of P3HT was significantly improved by addition of BCNs, which led to over one order of magnitude higher conductivity for the composite containing 1–2 wt% BCNs in P3HT. In the meantime, the interfacial charge transfer between the MAPbI3 light absorbing layer and the HTM composite layer based on P3HT/BCNs was two-fold faster than pristine P3HT. More importantly, the HTM film with a superior morphological structure consisting of closely compact large grains was achieved with the composite containing 1 wt% BCNs in P3HT. The study by electrochemical impedance spectroscopy has confirmed that the electron recombination in the solar cells was reduced nearly ten-fold with the addition of 1 wt% carbon nanotubes in the HTM composite. Owing to the superior HTM film morphology and the significantly reduced charge recombination, the energy conversion efficiency of the perovskite solar cells increased from 3.6% for pristine P3HT to 8.3% for P3HT/(1 wt% BCNs) with a significantly enhanced open circuit voltage (Voc) and fill factor (FF). The findings of this work are important for development of new HTM for high performance perovskite solar cells.

A Submission to the Joint Standing Committee on Treaties on the Anti-Counterfeiting Trade Agreement 2011 (# ACTA)

“If Hollywood could order intellectual property laws for Christmas, what would they look like? This is pretty close.” David Fewer “While European and American IP maximalists have pushed for TRIPS-Plus provisions in FTAs and bilateral agreements, they are now pushing for TRIPS-Plus-Plus protections in these various forums.” Susan Sell “ACTA is a threat to the future of a free and open Internet.” Alexander Furnas “Implementing the agreement could open a Pandora's box of potential human rights violations.” Amnesty International. “I will not take part in this masquerade.” Kader Arif, Rapporteur for the Anti-Counterfeiting Trade Agreement 2011 in the European Parliament Executive Summary As an independent scholar and expert in intellectual property, I am of the view that the Australian Parliament should reject the adoption of the Anti-Counterfeiting Trade Agreement 2011. I would take issue with the Department of Foreign Affairs and Trade’s rather partisan account of the negotiations, the consultations, and the outcomes associated with the Anti-Counterfeiting Trade Agreement 2011. In my view, the negotiations were secretive and biased; the local consultations were sometimes farcical because of the lack of information about the draft texts of the agreement; and the final text of the Anti-Counterfeiting Trade Agreement 2011 is not in the best interests of Australia, particularly given that it is a net importer of copyright works and trade mark goods and services. I would also express grave reservations about the quality of the rather pitiful National Interest Analysis – and the lack of any regulatory impact statement – associated with the Anti-Counterfeiting Trade Agreement 2011. The assertion that the Anti-Counterfeiting Trade Agreement 2011 does not require legislative measures is questionable – especially given the United States Trade Representative has called the agreement ‘the highest-standard plurilateral agreement ever achieved concerning the enforcement of intellectual property rights.’ It is worthwhile reiterating that there has been much criticism of the secretive and partisan nature of the negotiations surrounding the Anti-Counterfeiting Trade Agreement 2011. Sean Flynn summarizes these concerns: "The negotiation process for ACTA has been a case study in establishing the conditions for effective industry capture of a lawmaking process. Instead of using the relatively transparent and inclusive multilateral processes, ACTA was launched through a closed and secretive “‘club approach’ in which like-minded jurisdictions define enforcement ‘membership’ rules and then invite other countries to join, presumably via other trade agreements.” The most influential developing countries, including Brazil, India, China and Russia, were excluded. Likewise, a series of manoeuvres ensured that public knowledge about the specifics of the agreement and opportunities for input into the process were severely limited. Negotiations were held with mere hours notice to the public as to when and where they would be convened, often in countries half away around the world from where public interest groups are housed. Once there, all negotiation processes were closed to the public. Draft texts were not released before or after most negotiating rounds, and meetings with stakeholders took place only behind closed doors and off the record. A public release of draft text, in April 2010, was followed by no public or on-the-record meetings with negotiators." Moreover, it is disturbing that the Anti-Counterfeiting Trade Agreement 2011 has been driven by ideology and faith, rather than by any evidence-based policy making Professor Duncan Matthews has raised significant questions about the quality of empirical evidence used to support the proposal of Anti-Counterfeiting Trade Agreement 2011: ‘There are concerns that statements about levels of counterfeiting and piracy are based either on customs seizures, with the actual quantities of infringing goods in free circulation in any particular market largely unknown, or on estimated losses derived from industry surveys.’ It is particularly disturbing that, in spite of past criticism, the Department of Foreign Affairs and Trade has supported the Anti-Counterfeiting Trade Agreement 2011, without engaging the Productivity Commission or the Treasury to do a proper economic analysis of the proposed treaty. Kader Arif, Rapporteur for the Anti-Counterfeiting Trade Agreement 2011 in the European Parliament, quit his position, and said of the process: "I want to denounce in the strongest possible manner the entire process that led to the signature of this agreement: no inclusion of civil society organisations, a lack of transparency from the start of the negotiations, repeated postponing of the signature of the text without an explanation being ever given, exclusion of the EU Parliament's demands that were expressed on several occasions in our assembly. As rapporteur of this text, I have faced never-before-seen manoeuvres from the right wing of this Parliament to impose a rushed calendar before public opinion could be alerted, thus depriving the Parliament of its right to expression and of the tools at its disposal to convey citizens' legitimate demands.” Everyone knows the ACTA agreement is problematic, whether it is its impact on civil liberties, the way it makes Internet access providers liable, its consequences on generic drugs manufacturing, or how little protection it gives to our geographical indications. This agreement might have major consequences on citizens' lives, and still, everything is being done to prevent the European Parliament from having its say in this matter. That is why today, as I release this report for which I was in charge, I want to send a strong signal and alert the public opinion about this unacceptable situation. I will not take part in this masquerade." There have been parallel concerns about the process and substance of the Anti-Counterfeiting Trade Agreement 2011 in the context of Australia. I have a number of concerns about the substance of the Anti-Counterfeiting Trade Agreement 2011. First, I am concerned that the Anti-Counterfeiting Trade Agreement 2011 fails to provide appropriate safeguards in respect of human rights, consumer protection, competition, and privacy laws. It is recommended that the new Joint Parliamentary Committee on Human Rights investigate this treaty. Second, I argue that there is a lack of balance to the copyright measures in the Anti-Counterfeiting Trade Agreement 2011 – the definition of piracy is overbroad; the suite of civil remedies, criminal offences, and border measures is excessive; and there is a lack of suitable protection for copyright exceptions, limitations, and remedies. Third, I discuss trade mark law, intermediary liability, and counterfeiting. I express my concerns, in this context, that the Anti-Counterfeiting Trade Agreement 2011 could have an adverse impact upon consumer interests, competition policy, and innovation in the digital economy. I also note, with concern, the lobbying by tobacco industries for the Anti-Counterfeiting Trade Agreement 2011 – and the lack of any recognition in the treaty for the capacity of countries to take measures of tobacco control under the World Health Organization Framework Convention on Tobacco Control. Fourth, I note that the Anti-Counterfeiting Trade Agreement 2011 provides no positive obligations to promote access to essential medicines. It is particularly lamentable that Australia and the United States of America have failed to implement the Doha Declaration on the TRIPS Agreement and Public Health 2001 and the WTO General Council Decision 2003. Fifth, I express concerns about the border measures in the Anti-Counterfeiting Trade Agreement 2011. Such measures lack balance – and unduly favour the interests of intellectual property owners over consumers, importers, and exporters. Moreover, such measures will be costly, as they involve shifting the burden of intellectual property enforcement to customs and border authorities. Interdicting, seizing, and destroying goods may also raise significant trade issues. Finally, I express concern that the Anti-Counterfeiting Trade Agreement 2011 undermines the role of existing international organisations, such as the United Nations, the World Intellectual Property Organization and the World Trade Organization, and subverts international initiatives such as the WIPO Development Agenda 2007. I also question the raison d'être, independence, transparency, and accountability of the proposed new ‘ACTA Committee’. In this context, I am concerned by the shift in the position of the Labor Party in its approach to international treaty-making in relation to intellectual property. The Australian Parliament adopted the Australia-United States Free Trade Agreement 2004, which included a large Chapter on intellectual property. The treaty was a ‘TRIPs-Plus’ agreement, because the obligations were much more extensive and prescriptive than those required under the multilateral framework established by the TRIPS Agreement 1994. During the debate over the Australia-United States Free Trade Agreement 2004, the Labor Party expressed the view that it would seek to mitigate the effects of the TRIPS-Plus Agreement, when at such time it gained power. Far from seeking to ameliorate the effects of the Australia-United States Free Trade Agreement 2004, the Labor Government would seek to lock Australia into a TRIPS-Double Plus Agreement – the Anti-Counterfeiting Trade Agreement 2011. There has not been a clear political explanation for this change in approach to international intellectual property. For both reasons of process and substance, I conclude that the Australian Parliament and the Australian Government should reject the Anti-Counterfeiting Trade Agreement 2011. The Australian Government would do better to endorse the Washington Declaration on Intellectual Property and the Public Interest 2011, and implement its outstanding obligations in respect of access to knowledge, access to essential medicines, and the WIPO Development Agenda 2007. The case study of the Anti-Counterfeiting Trade Agreement 2011 highlights the need for further reforms to the process by which Australia engages in international treaty-making.

Synthesis and luminescent properties of star-burst D-Pi-A compounds based on 1,3,5-triazine core and carbazole end-capped phenylene ethynylene arms

Two new star-burst compounds based on 1,3,5-triazine core and carbazole end-capped phenylene ethynylene arms (1a and 1b) were synthesized and characterized. Their photophysical properties were investigated systematically via spectroscopic and theoretical methods. Both compounds exhibit strong 1π–π⁎ transitions in the UV region and intense 1π–π⁎/intramolecular charge transfer (1ICT) absorption bands in the UV–vis region. Introducing the carbazole end-capped phenylene ethynylene arm on the 1,3,5-triazine core causes a slight bathochromic shift and enhanced molar extinction coefficient of the 1π–π⁎/1ICT transition band. Both compounds are emissive in solution at room temperature and 77 K, which exhibit pronounced positive solvatochromic effect. The emitting state could be ascribed to 1ICT state in more polar solvent, and 1π–π⁎ state in low-polarity solvent. The high emission quantum yields (Φem=0.90~1.0) of 1a and 1b (in hexane and toluene) make them potential candidates as efficient light-emitting materials. The spectroscopic studies and theoretical calculations indicate that the photophysical properties of these compounds can be tuned by the carbazole end-capped phenylene ethynylene arm, which would also be useful for rational design of photofunctional materials.

The application of islanded photovoltaic cells and battery storage on the reliability of distribution networks

Renewable energy resources, in particularly PV and battery storage are increasingly becoming part of residential and agriculture premises to manage their electricity consumption. This thesis addresses the tremendous technical, financial and planning challenges for utilities created by these increases, by offering techniques to examine the significance of various renewable resources in electricity network planning. The outcome of this research should assist utilities and customers for adequate planning that can be financially effective.