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International audience; Nanoparticle organic photovoltaics, a subfield of organic photovoltaics (OPV), has attracted increasing interest in recent years due to the eco-friendly fabrication of solar modules afforded by colloidal ink technology. Importantly, using this approach it is now possible to engineer the microstructure of the light absorbing/charge generating layer of organic photovoltaics; decoupling film morphology from film deposition. In this study, single-component nanoparticles of poly(3-hexylthiophene) (P3HT) and phenyl-C61 butyric acid methyl ester (PC61BM) were synthesized and used to generate a two-phase microstructure with control over domain size prior to film deposition. Scanning transmission X-ray microscopy (STXM) and electron microscopy were used to characterize the thin film morphology. Uniquely, the measured microstructure was a direct input for a nanoscopic kinetic Monte Carlo (KMC) model allowing us to assess exciton transport properties that are experimentally inaccessible in these singlecomponent particles. Photoluminescence, UV−vis spectroscopy measurements, and KMC results of the nanoparticle thin films enabled the calculation of an experimental exciton dissociation efficiency (ηED) of 37% for the two-phase microstructure. The glass transition temperature (Tg) of the materials was characterized with dynamic mechanical thermal analysis (DMTA) and thermal nnealing led to an increase in ηED to 64% due to an increase in donor−acceptor interfaces in the thin film from both sintering of neighboring opposite-type particles in addition to the generation of a third mixed phase from diffusion of PC61BM into amorphous P3HT domains. As such, this study demonstrates the higher level of control over donor−acceptor film morphology enabled by customizing nanoparticulate colloidal inks, where the optimal three-phase film morphology for an OPV photoactive layer can be designed and engineered.

Organoleptic properties of old apple cultivars evaluated by sensory analysis. In the framework of a research programme focused on the evaluation and the valorization of fruit tree genetic resources, the sensory analysis technique has been used in order to evaluate the organoleptic properties of six old apple cultivars which are on trial in Belgium and North of France. The aims were to define their optimal picking time and storage aptitude, therefore marketing advices could be given to growers. Methodological aspects have been investigated on different sensory analysis parameters adapted to fresh fruits e.g. panel selection and formation, choice of descriptors. Sensory analysis was applied just after picking and periodically during the storage period. For each fruit sample, different characteristics were measured (brix, pH and flesh firmness) with the objective to calculate the correlation between sensory analysis data and analytical data. The results show that for the Jonagold cv., there is a very high correlation between ""crunchiness"", ""flesh firmness"" and ""juiciness"" sensory evaluated data. Other results, based on the experimentation of the six old cvs, confirm the correlation between the sensory analysis of the ""flesh firmness"" and the ""juiciness"", they show that the ""flesh firmness"" can be well assessed by a sensory analysis panel, and that the global fruit quality appreciation depends mostly on ""juiciness"", ""flesh firmness"" and sweet sensation. The sensory analysis can give good indication for a better commercial management of apple cvs concerning picking date, storage capacity and the best storage conditions to be chosen.

The formation of the surface-induced stratified lamellar composition profile experimentally evidenced in spincoated layers of the photovoltaic donor-acceptor blend consisting of poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-5,5- (4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole]/ phenyl-C61-butyric acid methyl ester (APFO-3/PCBM), as processed from chloroform, is simulated using square gradient theory extended with terms describing the interaction of the blend components with the air and substrate interfaces. The surface energy contributions have been formulated based on an enthalpic nearest-neighbor model which allows integration of common surface tension theory and experimentally accessible surface energies of the fluid phase constituents with a mean field description of a multicomponent blend confined by substrate and air interfaces. Using estimates for the quench depth and transport properties of the blend components as a function of polymer concentration, the time-resolved numerical simulations yield results that compare favorably with experimental observations, both in terms of the number of lamellae as a function of the blend layer thickness and their compositional order. The effect of blend ratio is reproduced as well, the lamellar pattern becoming more pronounced if the amount of PCBM increases relative to APFO-3. © 2013 American Chemical Society.

Several strategies to form multicomponent films of functional polymers, with micron, submicron and nanometer structures, intended for plastic electronics and biotechnology are presented. These approaches are based on film deposition from polymer solution onto a rotating substrate (spin-casting), a method implemented already on manufacturing lines. Film structures are determined with compositional (nanometer) depth profiling and (submicron) imaging modes of dynamic secondary ion mass spectrometry, near-field scanning optical microscopy (with submicron resolution) and scanning probe microscopy (revealing nanometer features). Self-organization of spin-cast polymer mixtures is discussed in detail, since it offers a one-step process to deposit and align simultaneously domains, rich in different polymers, forming various device elements: (i) Surface segregation drives self-stratification of nanometer lamellae for solar cells and anisotropic conductors. (ii) Cohesion energy density controls morphological transition from lamellar (optimal for encapsulated transistors) to lateral structures (suggested for light emitting diodes with variable color). (iii) Selective adhesion to substrate microtemplates, patterned chemically, orders lateral structures for plastic circuitries. (iv) Submicron imprints of water droplets (breath figures) decorate selectively micron-sized domains, and can be used in devices with hierarchic structure. In addition, selective protein adsorption to regular polymer micropatterns, formed with soft lithography after spin-casting, suggests applications in protein chip technology. An approach to reduce lateral blend film structures to submicron scale is also presented, based on (annealed) films of multicomponent nanoparticles.

Evaluaties van het milieubeleid zijn in Vlaanderen een relatief recent fenomeen. Milieueffecten rapportering (MER) en regulatory impact analysis (RIA) zijn wettelijke verplichtingen voor projecten en beleidsmaatregelen met een mogelijk belangrijke impact op het leefmilieu. Om zinvolle resultaten uit deze milieubeleidsanalyses te krijgen, is het echter belangrijk om op een systematische manier te werken. De tien stappen die we in dit artikel uitwerken bieden een algemeen kader dat op verschillende types milieuproblemen toepasbaar is. Elke stap wordt geïllustreerd aan de hand van het Vlaamse bosbeleid.