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.

The entangled triplet pair state in acene and heteroacene materials.

Abstract: Entanglement of states is one of the most surprising and counter-intuitive consequences of quantum mechanics, with potent applications in cryptography and computing. In organic materials, one particularly significant manifestation is the spin-entangled triplet-pair state, which mediates the spin-conserving fission of one spin-0 singlet exciton into two spin-1 triplet excitons. Despite long theoretical and experimental exploration, the nature of the triplet-pair state and inter-triplet interactions have proved elusive. Here we use a range of organic semiconductors that undergo singlet exciton fission to reveal the photophysical properties of entangled triplet-pair states. We find that the triplet pair is bound with respect to free triplets with an energy that is largely material independent (∼30 meV). During its lifetime, the component triplets behave cooperatively as a singlet and emit light through a Herzberg-Teller-type mechanism, resulting in vibronically structured photoluminescence. In photovoltaic blends, charge transfer can occur from the bound triplet pairs with >100% photon-to-charge conversion efficiency.

Gas barrier properties of poly(ε‐caprolactone)/clay nanocomposites: Influence of the morphology and polymer/clay interactions

Abstract: Poly(-caprolactone)/montmorillonite nanocomposites were prepared main- taining a constant inorganic content with three means: melt blending of poly(-capro- lactone) with natural or organomodified clays, in situ polymerization of -caprolactone in the presence of organomodified clays, and initiation of -caprolactone polymerization from the silicate layer with appropriate organomodified montmorillonites and activa- tor. In this last case, the polymer chains were grafted to the silicate layers and it was possible to tune up the grafting density. The presence of clays did not modify the polymer crystallinity. It was shown that the in situ polymerization process from the clay surface improved the clay dispersion. The gas barrier properties of the different composite systems were discussed both as a function of the clay dispersion and of the matrix/clay interactions. The highest barrier properties were obtained for an exfoliated morphology and the highest grafting density. Similar evolution of the permeability and the diffusion coefficients was observed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 205-214, 2005