University of Mons

About: University of Mons is a education organization based out in Mons, Belgium. It is known for research contribution in the topics: Large Hadron Collider & Standard Model. The organization has 3073 authors who have published 9465 publications receiving 294776 citations.

25th Anniversary Article: High‐Mobility Hole and Electron Transport Conjugated Polymers: How Structure Defines Function

Abstract: The structural organization of three different families of semicrystalline π-conjugated polymers is reported (poly(3-hexylthiophene) (P3HT), poly[2,6-(4,4-bis-alkyl-4H-cyclopenta-[2,1-b;3,4-b0]-dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)](cyclopentadithiophene-benzothiadiazole) (CDT-BTZ) and poly(N,N"-bis-2-octyldodecylnaphtalene-1,4,5,8-bis-dicarboximide-2,6-diyl-alt-5,5–2,2-bithiophene (P(NDI2OD-T2))). These have triggered significant interest for their remarkable charge-transport properties. By performing molecular mechanics/dynamics simulations with carefully re-parameterized force fields, it is illustrated in particular how the supramolecular organization of these conjugated polymers is driven by an interplay between the length and nature of the conjugated monomer unit and the packing of their alkyl side chains, and to what extent it impacts the charge-carrier mobility, as monitored by quantum-chemical calculations of the intermolecular hopping transfer integrals. This Progress Report is concluded by providing generic guidelines for the design of materials with enhanced degrees of supramolecular organization.

Thermoelectric properties of conducting polymers : The case of poly(3-hexylthiophene)

Abstract: Conducting polymers have recently been suggested as thermoelectric materials for use in large-area thermogenerators. To help assessing the feasibility of this the electrical conductivity and Seebeck coefficient of a series of heavily doped regioregular poly(3-hexylthiophene) films are measured between 220 and 370 K. $p$-type chemical doping of up to 34% is accompanied by the introduction of negatively charged counterions, ${\text{PF}}_{6}^{\ensuremath{-}}$. The counterions produce a disordered environment within which the $p$-type electronic carriers move. This disorder diminishes with increasing doping as the effect of the counterions is smoothed out. Concomitantly the thermally activated electrical conductivity rises strongly while its activation energy decreases. On the other hand, the Seebeck coefficient is found to be weakly dependent on temperature and it decreases with increasing doping. When combined, these results indicate that the thermoelectric power factor reaches a broad maximum between 20% and 31% doping. These results are discussed in terms of the thermally activated hopping-type mobility of bipolarons, deduced from the absence of electron spin resonance signal in the heavily doped materials.

Measurement of jet fragmentation in PbPb and pp collisions at root s(NN)=2.76 TeV

Abstract: The jet fragmentation function of inclusive jets with transverse momentum p_T above 100GeV/c in PbPb collisions has been measured using reconstructed charged particles with p_T above 1GeV/c in a cone of radius 0.3 around the jet axis. A data sample of PbPb collisions collected in 2011 at a nucleon-nucleon center-of-mass energy of √sNN = 2.76 TeV corresponding to an integrated luminosity of 150μb^(−1) is used. The results for PbPb collisions as a function of collision centrality and jet transverse momentum are compared to reference distributions based on pp data collected at the same center-of-mass energy in 2013, with an integrated luminosity of 5.3pb^(−1). A centrality-dependent modification of the fragmentation function is found. For the most central collisions, a significant enhancement is observed in the PbPb/pp fragmentation function ratio for charged particles with p_T less than 3GeV/c. This enhancement is observed for all jet p_T bins studied.

Study of the inclusive production of charged pions, kaons, and protons in pp collisions at √s = 0.9,2.76 and 7 TeV

Abstract: Spectra of identified charged hadrons are measured in pp collisions at the LHC for sqrt(s) = 0.9, 2.76, and 7 TeV. Charged pions, kaons, and protons in the transverse-momentum range pt approximately 0.1-1.7 GeV and for rapidities abs(y) < 1 are identified via their energy loss in the CMS silicon tracker. The average pt increases rapidly with the mass of the hadron and the event charged-particle multiplicity, independently of the center-of-mass energy. The fully corrected pt spectra and integrated yields are compared to various tunes of the PYTHIA6 and PYTHIA8 event generators.

Measurement of South Pole ice transparency with the IceCube LED calibration system

Abstract: The IceCube Neutrino Observatory, approximately 1 km(3) in size, is now complete with 86 strings deployed in the Antarctic ice. IceCube detects the Cherenkov radiation emitted by charged particles passing through or created in the ice. To realize the full potential of the detector, the properties of light propagation in the ice in and around the detector must be well understood. This report presents a new method of fitting the model of light propagation in the ice to a data set of in situ light source events collected with IceCube. The resulting set of derived parameters, namely the measured values of scattering and absorption coefficients vs. depth, is presented and a comparison of IceCube data with simulations based on the new model is shown. Published by Elsevier B.V.