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Luminescent radicals are attracting attention as emitters in electroluminescent devices thanks to the exploitation of doublet excitons. Recent studies reveal that exciton formation in radical organic light‐emitting diodes (OLEDs) primarily occurs through a charge trapping mechanism. Although typically detrimental for OLEDs, this might be a key process to elucidate light emission in organic light‐emitting transistors (OLETs). Here, a unipolar n‐type architecture suitable for the implementation of radical emitters is introduced, designed based on computational calculations. The operation of the as‐realized devices incorporating the newly synthesized [2,6‐dichloro‐4‐(2,6‐dimethoxyphenyl)phenyl](3,5‐dichloro‐4‐pyridyl) (2,4,6‐trichlorophenyl)methyl radical is investigated via transient electroluminescence measurements to demonstrate the occurrence of long‐living emission ascribed to the charge trapping mechanisms. Moreover, a comprehensive understanding of the processes governing radical‐OLET is obtained by recording complete 2D maps of both optical and electrical response of the device as a function of applied voltages. Notably, the trapping of electrons by radical moieties is demonstrated to generate a negative charge density in the emissive layer that facilitates holes to be injected: increasing the balance of opposite charge carriers, a tenfold enhancement of the external quantum efficiency (EQE) at the proper source‐drain and source‐gate voltage conditions is reported to reach a maximum EQE value of 0.2%. [ABSTRACT FROM AUTHOR]

Introducing lignocellulosic fibers as the matrix reinforcement in composites is an opportunity for weight reduction and also for the use of by-products and biomass waste from other systems, such as agriculture and textiles. In the case of nautical applications, biofouling, meaning damage during service by marine organisms, represents a significant issue. To address this problem, a number of measures can be taken: these include the introduction of various types of fillers, mainly mineral, in composites, tailored treatment of fibers, and hybrid approaches, including a number of different modifications, such as matrix or fiber grafting. This review reports the state of the art in the various studies carried out to elucidate the performance of natural fiber composites and hybrids as regards water absorption and more specifically exposure to seawater for a prolonged time so as to simulate service conditions. The perspectives on the use of natural fiber composites (NFCs) in aquatic environments will be discussed with respect to the possible onset of degradation by biofouling. [ABSTRACT FROM AUTHOR]

Analytical techniques are essential in investigating the unique features of extra‐terrestrial geomaterials, and the use of in situ analytical tools is becoming increasingly common, as it facilitates a quick initial bulk chemical analysis, identification and classification. In this work, a handheld laser‐induced breakdown spectroscopy (hLIBS) instrument has been used to identify the qualitative and quantitative composition, and generate compositional micro‐maps, of a suite of iron meteorite samples representative of the different chemical and structural classes by analysing the spectra released from the plasma formed by the laser impact. Furthermore, the analytical performance of hLIBS was compared with that of portable X‐ray fluorescence spectrometry (pXRF). The analytical precision and accuracy of the calibration curves previously built in the laboratory for a set of certified reference metal alloys was assessed, so that the same protocol could be used to measure those of the investigated iron meteorites. A good agreement was achieved between hLIBS and reference data in the quantitative estimate of the elements Fe, Ni, Co and Cu. An attempt to quantify Ga by LIBS in two classified iron meteorites was also successful. [ABSTRACT FROM AUTHOR]

Triplet–triplet annihilation (TTA), or triplet fusion, is a biexcitonic process in which two triplet‐excited molecules can combine their energy to promote one into an excited singlet state. To alleviate the dependence of the TTA rate and yield on triplet diffusion in both solid and solution environments, intramolecular TTA (intra‐TTA) has been recently proposed in conjugated molecular systems able to hold multiple triplet excitons simultaneously. Developing from the previous demonstration of TTA performance enhancement in sensitized upconversion solutions, here similar improvements in triplet harvesting in solid‐state films are reported under electrical excitation in organic light emitting diodes (OLEDs). At low dye concentration and low current densities, the intra‐TTA active OLED shows a +40% improved external quantum efficiency with respect to the reference device, and a TTA spin‐statistical factor f 4DPA of 0.4, close to that determined in fluid solution for the individual chromophore (0.45). These results therefore indicate the utility of this molecular design strategy across a wider range of TTA applications, and with particular utility in the further development of low‐power TTA‐enhanced OLEDs. [ABSTRACT FROM AUTHOR]

Protein gels prepared by keratin extracted from chicken feathers show potential applications as engineered materials. Feathers are an abundant waste material, whose principal component is keratin, which may have gelling properties not yet sufficiently studied so far which are strongly dependent on the extraction method adopted. The aim of the study is to explore the properties of gels obtained through mercaptoethanol extraction and dialysis process and to evaluate their structural characteristics. The keratin hydrogels were characterized with Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy through which it was possible to identify the secondary structure of the protein on hydrated and dry gel. Moreover, the morphological analysis by scanning electron microscopy (SEM) combined with the rheological analysis showed how the consistency of the gels is maintained on a wide range of loads and frequencies. Furthermore, the biocompatibility of the gels was investigated for the release of subcutaneous drugs using curcumin, an antioxidant polyphenol compound. The fastest release was obtained at pH 7.4, corresponding to physiological conditions. [ABSTRACT FROM AUTHOR]

This account summarizes the impact that the quest for sustainability is having on the field of organic polyconjugate molecules and polymers for plastic (opto)electronics. While at the proof-of-concept level, the design criteria as well as the preferred synthetic strategies to access new and improved materials have been dominated by the need for performance. The ongoing transition from the lab environment to the industrial scale imposes strict limitations on the cost and overall environmental impact of new materials. We here summarize our efforts on the development of new design criteria and synthetic strategies aimed at improving sustainability – without compromising performance – in organic polyconjugated molecules. The article is composed of three sections: Introduction and motivation, sustainability through improved synthetic methods and through improved design. Outline 1 Introduction and Motivation 2 Sustainable Reaction Methods 2.1 The New Tools: Reactions in Aqueous Solution of Surfactants 2.2 Intrinsically More Sustainable Reactions: Direct Arylation 2.3 Sustainable Multistep Protocols: Combining Micellar, Solventless, and Mechanochemical Methods 3 Sustainability as a Design Criterion: De Novo Design 4 Conclusion [ABSTRACT FROM AUTHOR]

Sonogashira coupling is one of the cornerstone Palladium mediated cross coupling reactions, giving a direct and high yield access to symmetric and non‐symmetric alkynes with high tolerance of substituents. The method generally requires the use of CuI as a cocatalyst, an inert atmosphere to protect palladium catalyst, somewhat harsh conditions like prolonged heating and the use of organic solvents due to the hydrophobicity of reagents and products. Leveraging on the opportunities offered by micellar catalysis, we here present a general methodology to perform Sonogashira coupling in water, with moderate or no heating, under air, without copper co‐catalysts and at very low catalyst loading. The method offers the same generality and scope of organic solvents based couplings, but strongly improves sustainability while offering excellent yields. [ABSTRACT FROM AUTHOR]

Molecular doping can increase the conductivity of organic semiconductors and plays an increasingly important role in emerging and established plastic electronics applications. 4-(1,3-Dimethyl-2,3-dihydro-1H-benzimidazol-2-yl)-N,N-dimethylaniline (N-DMBI-H) and tris(pentafluorophenyl)borane (BCF) are established n- and p-dopants, respectively, but neither functions as a simple one-electron redox agent. Molecular hydrogen has been suggested to be a byproduct in several proposed mechanisms for doping using both N-DMBI-H and BCF. In this paper we show for the first time the direct detection of molecular hydrogen in the uncatalysed doping of a variety of polymeric and molecular semiconductors using these dopants. Our results provide insight into the doping mechanism, providing information complementary to that obtained from more commonly applied methods such as optical, electron spin resonance, and electrical measurements. [ABSTRACT FROM AUTHOR]

In this work, the characteristic structure of keratin extracted from two different kinds of industrial waste, namely sheep wool and chicken feathers, using the sulfitolysis method to allow film deposition, has been investigated. The structural and microscopic properties have been studied by means of scanning electron microscopy (SEM), Raman spectroscopy, atomic force microscopy (AFM), and infrared (IR) spectroscopy. Following this, small-angle X-ray scattering (SAXS) analysis for intermediate filaments has been performed. The results indicate that the assembly character of the fiber can be obtained by using the most suitable extraction method, to respond to hydration, thermal, and redox agents. The amorphous part of the fiber and medium range structure is variously affected by the competition between polar bonds (reversible hydrogen bonds) and disulfide bonds (DB), the covalent irreversible ones, and has been investigated by using fine structural methods such as Raman and SAXS, which have depicted in detail the intermediate filaments of keratin from the two different animal origins. The preservation of the secondary structure of the protein obtained does offer a potential for further application of the waste-obtained keratin in polymer films and, possibly, biocomposites. [ABSTRACT FROM AUTHOR]