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Viewing upcoming talks containing the keyword: 19
Speaker: Sylvia Draper (Trinity College Dublin)
The ‘Opti -mystic’ Tailoring of C onjugated Light -emitting Materials S.M.Draper ,a* L.P.Wijesinghe, a Y.Lu, a C.Delaney, a aSchool of Chemistry, Trinity College, the University of Dublin, D2, Ireland Email: firstname.lastname@example.org
Over the last two decades great strides have been made in the development of new materials and device architectures which tap into the superior electronic and optical properties of heavy transition metal complexes e.g. as the phosphors in OLEDs where they offer 100% electro -harvesting of their singlet and triplet excitons (via spin -orbit coupling). To date the organic ligand s at the forefront of literature investigations comprise polyimines (bipyridine, phenanthroline, terpyridine and quaterpyridine with/without anchoring groups), long -range electron transfer motifs such alkenyl and alkynyl linkers, polyaromatic donor functio nalities such as anthracene and pyrene and hole and electron transporting units that include triphenylamine, bodipy and napthalamide. This paper will illustrate the valuable addition made to this field through the rare, extended, ligand motifs generated wi thin the Draper team 1-3 (Figure 1). In particular it will look at the synthetic challenges that must be overcome in order to tap into the notable potential of these materials as photosensitisers and NIR emitters in new emerging technologies. 4 Figure 1 (left and right) The dramatic effect of reduced aromaticity on the absorption properties of tris homoleptic Ru(II) complexes of N -HSB; (centre) the dimeric “paved” lattice -packing for the [(bipy) 2Os(NHSB)] 2+ complex, and the off -set stack of its Ru(II) an alogue . References. 1. L.P. W ijesinghe, B.S. Lankage, G.M. ÓMáille, S.D. Perera, D. Nolan, L. Wang, S.M. Draper*, Chem. Commun. , 2014 , 50 (73), 10637. 2. C. Delaney, G.M. Ó Máille, S.M. Draper*, Chem. Commun. , 2014 , 50 (13), 1599. 3. C. Delaney, G.M. Ó Máille, B. Twamley, S.M. Draper*, Org. Lett. , 2016 , 18 (1), pp 88 –91 4. D. Nolan, B. Gil, L. W ang, J.Z. Zhao and S.M. Draper*, Chemistry – A European Journal, 2013 , 19 (46), 15615. Download PDF
On: November 15, 2017 From: 14h00 To: 15h00View talk
Organic Semiconductor Centre
Speaker: Professor Anthony Harriman (Newcastle University)
Pressure is an important variable but has been largely overlooked in recent spectroscopic studies. Small changes in pressure are easily achieved and many pressure-sensitive (or touch-sensitive) devices are on the market. This is not the case for applications that rely on changes in fluorescence and so we have set out to design a new range of organic emitters that are highly sensitive to applied pressure. There is, in fact, no reason why radiative processes should depend on pressure other than to respond to minor changes in refractive index. Molecular topology, however, is more susceptible to changes in the environment and sensitivity towards pressure can be engineered by changing the molecular shape. Electronic energy transfer, for example, is dependent on the separation distance and mutual orientation of the donor and acceptor and these parameters can be tuned by applied pressure. Increased sensitivity requires that pressure causes a largescale change in the degree of p-conjugation running along the organic backbone. This presents a more difficult challenge to the designer but certain expanded BODIPY (boron dipyrromethene) dyes appear to possess the necessary features that allow reversible distortion of the molecular backbone under applied pressure. These various systems will be described.
On: November 15, 2017 From: 14h00 To: 15h00View talk
Chemical Probes of Natural Product Assemblies: Novel Biosynthetic Insights and Opportunities (EaStCHEM/BSRC Joint Colloquium)
Speaker: Manuela Tosin (Warwick)
Chemical Probes of N atural Product Assemblies : Novel Biosynthetic Insights and O pportunities Manuela Tosin Department of Chemistry, University of Warwick, Coventry, UK E-mail: email@example.com Natural products and their derivatives constitute a ma jor source of treatments for h uman, animal and plant diseases. A comprehensive mechanistic and temporal elucidation of natural product biosynthetic pathways is of the highest priority, as it paves the way to the generation of novel high -value molecules via enzyme and metabolic engineering . In our group we have devised a chem ical approach for the detailed investigation of polyketide and nonribosomal peptide product assembly : this consists in the use of chemical probes capable of ‘capturing ’ transient biosyn thetic intermediates in a readily analysable form .1 The knowledge of biosynthetic processing has allowed us to envisage new chemoenzymatic routes to natural product derivatives, such as to unnatural polyethers (Fig. 1). 2 Herein I will present our latest chemical tool development for the study of natural product enzymatic assemblies 3-6 and discuss key findings in view of their exploitation .
Figure 1 : Fuctionalised chemical probes ( 1) capable of reacting with polyketide synthase -bound intermediates 4 can be utilised for in vivo polyketide diversification. 2 Representative publications :
1. M. Tosin, * L. Smith, P. F. Leadlay, Angew. Chem. Int. Ed. 2011 , 50 , 11930 -11933. 2. E. Riva, I. Wilkening, S. Gazzola, W. M. A. Li, L. Smith, P. F. Leadlay, M. Tosin ,* Angew. Chem. Int. Ed. 2014 , 53 , 11944 -11949 . 3. J. S. Parascan dolo, J. Havemann, H. K. Potter, F. Huang, E. Riva, J. Connolly, I. Wilkening, L. Song, P. F. Leadlay, M. Tosin ,* Angew. Chem. Int. Ed . 2016 , 55, 3463 -7. 4. I. Wilkening, S. Gazzola, J. S. P arascandolo, E. Riva, L. Song, M. Tosin ,* Chem. Commun . 2016 , 52, 10392 -10395. 5. J. Havemann, M. E. Yurkovich, R. Jenkins, S. Harringer, W. Tao, S. Wen, Y. Sun, P. F. Leadlay, M. Tosin,* Chem. Commun . 2017 , 53 , 1912 -1915. 6. Y. T. C. Ho, D. J. Leng, F. Ghiringhelli, I. Wilkening, D. P. Bushell, O. Kostner, E. Riva, J. Havemann, D. Passarella, M. Tosin ,* Chem. Commun . 2017 , 53 , 7088 -7091 . Fermentation and Staudinger Fermentation and ‘Click’ Download PDF
On: November 22, 2017 From: 15h30 To: 16h30View talk
Cond Mat Seminars
Speaker: Marina Filip (University of Oxford)
Perovskite solar cells are emerging as one of the most promising photovoltaic technologies, havingexceeded the performance of thin-film silicon devices (beyond 21%) in only 5 years of development.This performance is exclusively due to the optimum optoelectronic properties of the prototypical organic-inorganic lead-halide perovskite, methylammonium lead-iodide (CH 3 NH 3 PbI 3 ), and related lead halides.The fast-paced development of the perovskite solar cells has not only fueled a growing interest into thefundamental physical properties of lead-halide perovskites, but has also been stimulating the design ofnew functional perovskites with tailor-made properties.
In the first part of my talk I will focus on the computational modelling of the optoelectronic propertiesof CH 3 NH 3 PbI 3 . I will give a brief introduction into the state-of-the-art first principles methods usedin our work, such as the density functional theory (DFT) and the GW approximation. I will presentour calculations of the quasiparticle band structure, band gap and charge carrier effective masses ofCH 3 NH 3 PbI 3 [1,2], and show that the GW approach is essential in the accurate description of theoptoelectronic properties of CH 3 NH 3 PbI 3 . Furthermore, I will show that by substituting the CH 3 NH 3cation with CH(NH 2 ) 2 , Cs, or Rb, the band gap of the lead-halide perovskites can be fine-tuned in thevisible range by engineering the steric interactions between the central cation and the inorganic PbI 6network .
In the second part of my talk I will present some of our most recent efforts into the computationaldesign of lead-free metal-halide perovskites for optoelectronics. In this part I will briefly outline thehigh-throughput computational strategy we have used in our search , and discuss the main outcomeof this screening, the computational discovery of two new lead-free semiconducting metal-halide doubleperovskites, Cs 2 BiAgCl 6 and Cs 2 BiAgBr 6 [6,7]. Filip, M.R., Verdi, C. and Giustino, F. J. Phys. Chem. C, 119 (45), 25209 (2015) Filip, M.R. and Giustino, F. J. Phys. Rev. B, 90 (24), 245145 (2014) Davies, C. L., Filip, M.R., Patel, J. B., Verdi, C., Milot, R. L., Giustino, F., Johnston, M. B. andHerz, L. M., Under Review (2017) Filip, M.R., Eperon, G. E., Snaith, H. J. and Giustino, F. J. Nat. Commun. 5, 5757 (2014) Filip, M.R. and Giustino, F. J. Phys. Chem. C, 120 (1), 166 (2016) Volonakis, G., Filip, M. R., Haghighirad, A. A., Sakai, N., Wenger, B., Snaith, H.J. and Giustino, F.,J Phys Chem Lett 7 (7) 1254-1259 (2016) Filip, M.R., Hillman, S., Haghighirad, A. A., Snaith, H. J. and Giustino, F., J. Phys. Chem. Lett. 7(13), 4554-4562 (2016)
On: November 22, 2017 From: 12h00 To: 13h00View talk
Physics and Astronomy Colloquia
Speaker: Elizabeth Blackburn (University of Birmingham)
The high-temperature superconductors were discovered just over 30 years ago. The initial observation was accompanied by an explosion of results probing and examining how they behaved, establishing some ground rules for the type of superconductivity observed – similar but different to the well-known BCS model for superconductivity. Over the last 5 years, there have been a number of breakthroughs in understanding the background from which the superconducting state develops. In this colloquium, I will pull together structural information, quantum oscillation, transport data and dynamical studies to describe the new observations, and look at how that helps with understanding high-temperature superconductivity, closing with the (many) open questions remaining.
On: December 1, 2017 From: 10h00 To: 11h00View talk
Physics and Astronomy Colloquia
Speaker: Ryan Hickox (University of Dartmouth)
At the heart of essentially every large galaxy in the Universe lies a supermassive black hole. In the past decade, surveys of the extragalactic sky have made great progress in understanding the cosmic growth of these black holes, as they "eat" surrounding material and radiate as active galactic nuclei (AGN). However, our picture of black hole evolution has remained incomplete, due to the challenges of detecting black holes that are highly obscured by gas and dust or hidden beneath thelight of their host galaxies. With the advent of new resources including hard X-ray observations from NuSTAR, mid-infrared data from WISE, and new insights from theoretical models, we can now identify millions of these “hidden” growing black holes across much the sky, and characterize the nature of their obscuration and their role in the formation of galaxies. I will describe recent efforts to characterize these "hidden” black holes, particularly highlighting work by our group at Dartmouth, and will present evidence that (at least some) powerful obscured AGN represent an evolutionary phase in the evolution of their host galaxies. Finally, I will point to the exciting potential for future of AGN population studies with the next generation of extragalactic surveys, including with NASA's Lynx concept X-ray mission.
On: December 8, 2017 From: 10h00 To: 11h00View talk