Photophysics and Photocurrent Generation in Polythiophene/Polyfluorene Copolymer Blends

Here, studies on the evolution of photophysics and device performance with annealing of blends of poly(3‐hexylthiophene) with the two polyfluorene copolymers poly((9,9‐dioctylfluorene)‐2,7‐diyl‐alt‐[4,7‐bis(3‐hexylthien‐5‐yl)‐2,1,3‐benzothiadiazole]‐2′,2′′‐diyl) (F8TBT) and poly(9,9‐dioctylfluorene‐co‐benzothiadiazole) (F8BT) are reported. In blends with F8TBT, P3HT is found to reorganize at low annealing temperatures (100 °C or below), evidenced by a redshift of both absorption and photoluminescence (PL), and by a decrease in PL lifetime. Annealing to 140 °C, however, is found to optimize device performance, accompanied by an increase in PL efficiency and lifetime. Grazing‐incidence small‐angle X‐ray scattering is also performed to study the evolution in film nanomorphology with annealing, with the 140 °C‐annealed film showing enhanced phase separation. It is concluded that reorganization of P3HT alone is not sufficient to optimize device performance but must also be accompanied by a coarsening of the morphology to promote charge separation. The shape of the photocurrent action spectra of P3HT:F8TBT devices is also studied, aided by optical modeling of the absorption spectrum of the blend in a device structure. Changes in the shape of the photocurrent action spectra with annealing are observed, and these are attributed to changes in the relative contribution of each polymer to photocurrent as morphology and polymer conformation evolve. In particular, in as‐spun films from xylene, photocurrent is preferentially generated from ordered P3HT segments attributed to the increased charge separation efficiency in ordered P3HT compared to disordered P3HT. For optimized devices, photocurrent is efficiently generated from both P3HT and F8TBT. In contrast to blends with F8TBT, P3HT is only found to reorganize in blends with F8BT at annealing temperatures of over 200 °C. The low efficiency of the P3HT:F8BT system can then be attributed to poor charge generation and separation efficiencies that result from the failure of P3HT to reorganize.     

Spray-coated SnO2 electron transport layer with high uniformity for planar perovskite solar cells

SnO₂ has been proven to be an effective electron transport layer(ETL)material for perovskite solar cells(PSCs)owing to its excellent electrical and optical properties.Here,we introduce a viable spray coating method for the preparation of SnO2 films.Then,we employ a SnO₂ film prepared using the spray coating method as an ETL for PSCs.The PSC based on the spray-coated SnO₂ ETL achieves a power conversion efficiency of 17.78%,which is comparable to that of PSCs based on conventional spin-coated SnO₂ films.The large-area SnO₂ films prepared by spray coating exhibit good repeatability for device performance.This study shows that SnO₂ films prepared by spray coating can be applied as ETLs for stable and high-efficiency PSCs.Because the proposed method involves low material consumption,it enables the low-cost and large-scale production of PSCs.     

Influence of a new crushing technique on the composition of the volatile compounds and related sensory quality of virgin olive oil

The influence of a new crusher i.e. blade crusher on the quality of virgin olive oil from two different italian cultivars (Coratina and Oliarola) was determined. In addition the quality of this oil was compared with that of olive oil extracted with the traditional hammer crusher. Tests were performed in an industrial oil mill using the two different crushing instruments. Results obtained showed that quality parameters i.e. free fatty acids, peroxide value, UV absorption and total phenols content as well as the phenolic composition of oils were not significantly affected by the two different crushers used. On the contrary, the use of the blade crusher influenced the composition of the volatile compounds. In particular, the oils obtained using the blade crusher showed significant increases of some aldehydes such as 1‐hexanal and trans‐2‐hexenal, esters such as hexyl acetate and 3‐hexenyl acetate and a reduction of alcohols such as 1‐hexanol. Moreover, the identified pigments of the oils produced using the blade crusher were found at concentrations slightly lower than those in oils obtained after using the hammer crusher. Finally, results of the sensory analysis showed an improved organoleptic quality for the oils obtained using the blade crusher due to an increase of the cut‐grass and floral sensory notes.     

Chemical composition of virgin olive oils from Koroneiki cultivar grown in Tunisia with regard to fruit ripening and irrigation regimes

The impact of different irrigation regimes based on two ripeness index, on the quantity and quality of virgin olive oil from the introduced olive cultivar Olea europaea L. Koroneiki grown at a high‐density olive orchard in northern Tunisia, was assessed. Olive trees were subjected to three treatments (T1, T2 and T3) that received a seasonal water amount equivalent to 50%, 75% and 100% of the estimated local evaporative demand by a drip irrigation system and olives were collected in two different ripeness index. The olive oil content decreased when the water applied was increased but rose during ripening. The quality indexes and fatty acid composition were less affected by the irrigation schedule but most significantly by the maturity of olives. Moreover, phenol contents increased according to fruit ripening whereas no clear cut differences or consistent effects were observed by irrigation. α‐tocopherol decreased slightly in the oils as ripening progressed while insignificant differences between the irrigation treatments studied were obtained. Consequently, a restitution of 75% of crop evapotranspiration (ET_c.) was sufficient to achieve good minor compounds; however, higher water volumes (100% ET_c.) gave little additional α‐tocopherol and phenols increases.     

Data Analysis and Double Pulse Identification for the MARE Experiment

One of the critical limits on the sensitivity of direct neutrino mass experiment, such as MARE, is the background generated by unidentified double pulses. In our work developing an analysis system for MARE we have focused on comparing algorithms, and developing and testing an optimum algorithm for the identification (and removal) of double pulses. To test the algorithms we developed a Monte Carlo simulation that, based on the detectors physical parameters, generates realistic single and double events with known characteristics. In this paper we present our preliminary results on two algorithms used for double pulse identification and their efficiency as a function of pulse heights and separation.     

Grappa quality from the Chianti and Montepulciano areas (Tuscany,Italy): monitoring the leaching of copper from distillation columns

The main aim of this work was to evaluate the leaching of copper in grappa from distillation plant that treats Cabernet and Sangiovese marcs (Montepulciano and Chianti, Tuscany). Copper content (determined by atomic absorption spectrometry, AAS) was 1.05 ± 0.03 mg L^?1 in industrial distillates (Cabernet marc, 82.3% alcohol, v/v), and 3.7 ± 0.2 μg L^?1 in artificial grappa (62.0%, Cabernet) obtained by distilling marc in a laboratory‐scale glassware plant. The artificial grappa distillate was refluxed over copper shavings, and copper content, C_Cu, was analysed in relation to reflux time and wear of the copper bell. The results showed that C_Cu trend was almost linear with increasing alcohol concentration and constant reflux time, and vice versa. The ratios of selected volatile components were not influenced by reflux on the shavings.     

Influence of Ion Induced Local Coulomb Field and Polarity on Charge Generation and Efficiency in Poly(3‐Hexylthiophene)‐Based Solid‐State Dye‐Sensitized Solar Cells

Dye‐sensitized solar cells (DSSC) are a realistic option for converting light to electrical energy. Hybrid architectures offer a vast materials library for device optimization, including a variety of metal oxides, organic and inorganic sensitizers, molecular, polymeric and electrolytic hole‐transporter materials. In order to further improve the efficiency of solid‐state dye‐sensitized solar cells, recent attention has focused on using light absorbing polymers such as poly(3‐hexylthiophene) (P3HT), to replace the more commonly used “transparent” 2,2′,7,7′‐tetrakis‐(N,N‐di‐p‐methoxyphenyl‐amine)9,9′spiro‐bifluorene (spiro‐OMeTAD), in order to enhance the light absorption within thin films. As is the case with spiro‐OMeTAD based solid‐state DSSC, the P3HT‐based devices improve significantly with the addition of lithium bis(trifluoromethylsulfonyl)imide salts (Li‐TFSI), although the precise role of these additives has not yet been clarified in solid‐state DSCs. Here, we present a thorough study on the effect of Li‐TFSI in P3HT based solid‐state DSSC incorporating an indolene‐based organic sensitizer termed D102. Employing ultrafast transient absorption and cw‐emission spectroscopy together with electronic measurements, we demonstrate a fine tuning of the energetic landscape of the active cell components by the local Coulomb field induced by the ions. This increases the charge transfer nature of the excited state on the dye, significantly accelerating electron injection into the TiO₂. We demonstrate that this ionic influence on the excited state energy is the primary reason for enhanced charge generation with the addition of ionic additives. The deepening of the relative position of the TiO₂ conduction band, which has previously been thought to be the cause for enhanced charge generation in dye sensitized solar cells with the addition of lithium salts, appears to be of minor importance in this system.     

Effects of Subtoxic Concentrations of Atrazine,Cypermethrin, and Vinclozolin on microRNA-Mediated PI3K/Akt/mTOR Signaling in SH-SY5Y Cells

Endocrine-disrupting chemicals (EDCs) are different natural and synthetic chemicals that may interfere with several mechanisms of the endocrine system producing adverse developmental, metabolic, reproductive, and neurological effects in both human beings and wildlife. Among pesticides, numerous chemicals have been identified as EDCs. MicroRNAs (miRNAs) can regulate gene expression, making fine adjustments in mRNA abundance and regulating proteostasis. We hypothesized that exposure to low doses of atrazine, cypermethrin, and vinclozolin may lead to effects on miRNA expression in SH-SY5Y cells. In particular, the exposure of SH-SY5Y cells to subtoxic concentrations of vinclozolin is able to downregulate miR-29b-3p expression leading to the increase in the related gene expression of ADAM12 and CDK6, which may promote a pro-oncogenic response through the activation of the PI3K/Akt/mTOR pathway and counteracting p53 activity. A better understanding of the molecular mechanisms of EDCs could provide important insight into their role in human disease.     

The effects of spacer arms in cross-linked hyaluronan hydrogel on Fbg and HSA adsorption and conformation

Four hyaluronan based hydrogels with different cross-linking agents were synthesised. Compounds with an increasing hydrophobic character and length as spacer arms were chosen, i.e. O,O′-bis(2 aminopropyl)polyethylen glicol, 1.3 diaminopropane, 1.6 diaminohexane, and 1.12 diaminedodecane. The cross-linking reaction involved 50% of the carboxylate groups present in the hyaluronan macromolecule chain. Hydrogels were characterised by water-uptake measurements and SEM analysis. The adsorption of two plasma proteins (HSA and Fbg) was analysed onto the four hydrogels in flow conditions by ATR-FTIR, evaluating the adsorption kinetics and the eventual protein conformational changes. The increasing hydrophobic character of the surface imposes a clear trend to the protein adsorption kinetics. The influence of the spacer arms on the protein conformation is evident on HSA, whereas Fbg does not seem to be significantly influenced by the change of the substrate hydrophobic properties.