Solvay

About: Solvay is a company organization based out in Brussels, Belgium. It is known for research contribution in the topics: Catalysis & Polymer. The organization has 6083 authors who have published 7004 publications receiving 105745 citations.

Two-step charge photogeneration dynamics in polymer/fullerene blends for photovoltaic applications

Abstract: Wemeasuredthepicoseconds(ps)transientdynamicsofphotoexcitationsinblendsofpoly(3-hexyl-thiophene) (P3HT; donors-D) and fullerene [6,6]-phenyl-C61-butyric acid methyl ester (PCBM; acceptor-A), using the transient pump/probe photomodulation technique in an unprecedented broad spectral range from 0.25 to 2.5 eV, and compared the results with organic solar cell performance based on the same blends. In D-A blends with maximumdomainseparationsuchasregio-regularP3HT/PCBMwith(1.2:1)weightratiohavingsolarcellpower conversion efficiency of ∼4%, we found that, although the photogenerated intrachain excitons in the polymer nano-domains decay within ∼10 ps, no charge polarons are generated on their expense up to ∼2 ns. Instead, there is a buildup of charge transfer (CT) excitons at the D-A interfaces having the same kinetics as the exciton decay, which dissociate into separate polarons in the D and A domains at a much later time (� 1 ns). This two-step charge photogeneration process may be typical in organic bulk heterojunction cells. Although the CT excitons are photogenerated on the exciton expense much faster in D-A blends having smaller domain size such as in regio-random P3HT/PCBM, their dissociation is less efficient because of larger binding energy. This explains the poor solar cell power conversion efficiency (<0.1%) based on this blend. Our results support the two-step charge photogeneration mechanism in polymer/fullerene blends and emphasize the important role of the CT binding energy in generating free charge polarons in organic solar cells.

Phenomenology of General Gauge Mediation in light of a 125 GeV Higgs

Abstract: We explore the phenomenology of the full General Gauge Mediation parameter space in the MSSM focusing on the consequences of having a fundamental Higgs around 125 GeV. Assuming GUT-complete structure of the hidden sector, we allow for deviations from the strict definition of gauge mediated SUSY-breaking coming from mild violations of messenger-parity and from extra couplings between the Higgs multiplets and the hidden sector. Relaxing the GUT assumption, our parameter space is defined by the property of having vanishing A-terms at the messenger scale. In this extended setup we focus on the possibility of splitting the SU(3) mass parameters of GGM. In all these scenarios we investigate the possible spectra, discussing to what extent having an Higgs mass around 125 GeV is constraining the GGM parameter space and what are the possible signatures at LHC.

Revisiting Hansen Solubility Parameters by Including Thermodynamics

Abstract: The Hansen solubility parameter approach is revisited by implementing the thermodynamics of dissolution and mixing. Hansen's pragmatic approach has earned its spurs in predicting solvents for polymer solutions, but for molecular solutes improvements are needed. By going into the details of entropy and enthalpy, several corrections are suggested that make the methodology thermodynamically sound without losing its ease of use. The most important corrections include accounting for the solvent molecules' size, the destruction of the solid's crystal structure, and the specificity of hydrogen-bonding interactions, as well as opportunities to predict the solubility at extrapolated temperatures. Testing the original and the improved methods on a large industrial dataset including solvent blends, fit qualities improved from 0.89 to 0.97 and the percentage of correct predictions rose from 54 % to 78 %. Full Matlab scripts are included in the Supporting Information, allowing readers to implement these improvements on their own datasets.

Process for the preparation of 1-chloro-1,1,3,3,3-pentafluoropropane and of 1,1,1,3,3,3-hexafluoropropane

Abstract: The invention relates to a process for the preparation of 1-chloro-1,1,3,3,3-pentafluoropropane and 1,1,1,3,3,3-hexafluoropropane by reaction in the liquid phase of 1,1,1,3,3,3-hexachloropropane with hydrogen fluoride in the presence of a catalyst.