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Why is modern physics still today, more than 100 years after its birth, the privilege of an elite of scientists and unknown for the great majority of citizens? The answer is simple, since modern physics is in general not present in the standard physics curricula, except for some general outlines, in the final years of some secondary schools. But, is it possible to teach modern physics in primary school? Is it effective? and, also, Is it engaging for students? These are the simple questions which stimulated our research, based on an intervention performed in the last year of Italian primary school, focused on teaching gravity, according to the Einsteinian approach in the spirit of the Einstein First project, an international collaboration which aims to teach school age children the concepts of modern physics. The outcomes of our research study are in agreement with previous findings obtained in Australian schools, thus they contribute to validate them and show that there is no cultural effect, since the approach works in different education systems. Finally, our results are relevant also in terms of retention and prove that the students involved really understand the key ideas.

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]

Doped organic semiconductors play a central role in the development of several innovative optoelectronic and energy harvesting applications. Currently, the realization of thermoelectric generators, which require both hole‐ and electron‐transporting materials with high electrical conductivity, is strongly hindered by the scarce availability of stable solution‐processable n‐dopants and their limited efficiency. Herein, the synthesis of 4‐(1,3‐dimethyl‐2,3‐dihydro‐1H‐benzimidazol‐2‐yl)‐dibenzazepine (IStBI), a novel derivative belonging to the well‐known family of the benzimidazoline compounds, is presented. The functionalization with the planarized and rigid iminostilbene substituent allows, without significantly affecting the compound electronic structure, an efficient intercalation of the dopant molecules inside the ordered regions of thin films of the benchmark n‐type polymer poly(N,N′‐bis‐2‐octyldodecylnaphthalene‐1,4,5,8‐bis‐dicarboximide‐2,6‐diyl‐alt‐5,5′‐2,2′‐bithiophene) P(NDI2OD‐T2). Consequently, a maximum electrical conductivity of (1.14 ± 0.13) × 10−2 S cm−1 is recorded, exceeding by one order of magnitude what previously achieved upon solution doping of the reference P(NDI2OD‐T2) with benzimidazoline derivatives. The thermoelectric power factor is also simultaneously increased. The findings confirm that tailoring of the dopant chemical structure to improve structural interactions with the host semiconductors can be employed as a successful strategy to achieve more effective n‐doping, helping to close the performance gap with p‐type materials. [ABSTRACT FROM AUTHOR]

Cesium lead halide perovskite nanocrystals of general formula CsPbX3 are having tremendous impact on a vast array of technologies requiring strong and tunable luminescence across the visible range and solutions processing. The development of plastic scintillators is just one of the many relevant applications. The syntheses are relatively simple but generally unsuitable to produce a large amount of material of reproducible quality required when moving from proof-of-concept scale to industrial applications. Wastes, particularly large amounts of lead-contaminated toxic and flammable organic solvents, are also an open issue. We describe a simple and reproducible procedure enabling the synthesis of luminescent CsPbX3 nanobricks of constant quality on a scale going from 0.12 to 8 g in a single batch. We also show complete recycling of the reaction wastes, leading to dramatically improved efficiency and sustainability. [ABSTRACT FROM AUTHOR]

Conjugated semiconducting polymers are key active materials for printable electronics, sensors and biosensors, organic photovoltaics, organic light emitting devices, and more. The research in the field developed very efficient materials and sound structure property relationships, thus making a case for a transition from laboratory to industrial environment. At this critical juncture, sustainability, and ease of scaling up are at least as important as performances, to the point that efficient materials on a lab scale could become unpractical for the industry. The development of more efficient synthetic protocols and the complete removal of all organic solvents from both the synthesis and the processing of semiconducting polymers can help tremendously to improve sustainability and reduce costs. It is shown that the use of an aqueous dispersion of the food grade surfactant lecithin as the medium, enables the synthesis and processing of the representative semiconducting alternating copolymer poly (9,9‐dioctylfluorene‐alt‐bithiophene) (PF8T2) in high yield and high quality and with transistor performances comparable with those obtained with reference materials synthetized and processed from volatile organic solvents. [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]

A highly crystalline, highly emissive, and wide-bandgap polymer AC174 with an extremely small Stokes shift is designed and synthesized in water, and is used to reduce system energetic disorder and increase the exciton diffusion length of the classical PM6:Y6 blend system. AC174 is incompatible with PM6 and Y6, improves molecular packing, and reduces system energetic disorder. The long-range Förster resonance energy transfer between the donor and acceptor is enhanced, and the exciton diffusion constant and exciton lifetime are increased, leading to a longer exciton diffusion length and more efficient exciton dissociation and charge generation. The addition of AC174 simultaneously improves the open-circuit voltage, short-circuit current density (JSC) and fill factor of PM6:Y6 devices; especially the highest internal quantum efficiency approaches 100%, and the highest JSC is 28.4 mA cm−2. Ternary devices with 5% AC174 in the donors achieve a power conversion efficiency of 17.2%, higher than those of the parent binary devices based on PM6:Y6 (15.9%) and AC174:Y6 (3.24%). [ABSTRACT FROM AUTHOR]

Quadruple addition of phenyl groups to a diphenylpyridylmethane skeleton was achieved. The derived (3,5-difluoro-4-pyridyl)bis(2,6-dichloro-3,4-diphenylphenyl)methyl radical (Ph4-F2PyBTM) displayed superior luminescence properties to the previously reported organic diphenylpyridylmethyl radicals in various organic solutions at room temperature, and it reached 33% photoluminescence quantum efficiency in PMMA film. With the introduction of methoxy groups, quadruple adduct (MeOPh)4–F2PyBTM and triple adduct (MeOPh)3–F2PyBTM were isolated. The excited state of these radicals showed an intramolecular charge transfer character and efficient fluorescence only in nonpolar solvents. The radicals retained not only persistency at the ground state but also durability under photoirradiation, with a 6 to 14 fold improved photostability with respect to the original PyBTM. [ABSTRACT FROM AUTHOR]

The impact on chiral aggregation in solution processed and thermally annealed thin films of two indolenine and one anilino squaraines with chiral (S)‐citronellyl functionalization at the nitrogen of the squaraine backbone is investigated. A pseudo polymorphic crystal structure is obtained for one of the indolenine squaraines, but thin films of both compounds are basically non‐aggregated and truly isotropic as evidenced by spectroscopic ellipsometry. The anilino squaraine coalesces and readily aggregates to circular dichroic but discontinuous thin films. The extent of circular dichroism correlates with the morphology of the samples, which is quantified by Mueller matrix polarimetry in combination with atomic force microscopy. The shape of the CD spectra reinforces the hybrid Frenkel and charge‐transfer excitonic nature of the characteristic double hump signatures within unpolarized absorbance spectra of previously investigated non‐chiral anilino squaraines with linear alkyl chain functionalization. Such excitonic CD offers an additional design parameter for next‐generation opto‐electronic devices. [ABSTRACT FROM AUTHOR]

Luminescent solar concentrators (LSCs) are becoming an increasingly relevant topic for building integrated photovoltaics. Even if such devices are relatively simple planar waveguides doped with a luminescent material, the achievement of relevant efficiencies requires a careful optimisation of both the matrix and the luminophore. Most of the recent literature focuses on the performance, yet the overall sustainability of the strategy is a topic at least as important. In this respect the luminophore plays a crucial role. Suitable materials must feature a near unit emission quantum yield, efficient light harvesting and a large separation between absorption and emission to reduce reabsorption losses. Due to the target application, such materials must also be readily available in large quantities through sustainable processes. Instead of going for performance first and then scaling up/optimising the synthesis, in this paper we offer a reversed perspective. We have first designed and computationally characterised materials having structural features compatible with a green chemistry synthetic approach, namely, micellar catalysis. Later, we have characterised the most promising materials in LSC devices, and we have compared their performance with commercially available, non-green chemistry compliant alternatives having similar spectral features. In the overall, we demonstrate comparable performance, but greatly improved sustainability and scalability. [ABSTRACT FROM AUTHOR]

Here, we report a [1]benzothieno[3,2-b][1]-benzothiophene (BTBT) derivative functionalized with a β-sheet-forming peptide which alternates in its sequence Phe and Glu residues. The BTBT core is a popular structural motif in the design of high-mobility organic semiconductors. The insertion of the self-assembling subunit allows control of the supramolecular organization. This molecule self-assembles in water to give hydrogels over a broad range of pH values. Hydrogelation is triggered by both pH changes and variations in salt concentrations. Transmission electron microscopy shows the formation of long-range self-assembled 1D structures. The key role of hydrogen bonding and π–π interactions in hierarchical self-assembly is investigated using absorption, emission, infrared and circular dichroism spectroscopy. This is the first example of demonstrating the formation of supramolecular hydrogels containing the BTBT structure. [ABSTRACT FROM AUTHOR]

The study of manufacture technologies and provenance of raw materials in archaeological potteries are two fundamental aspects in providing information about sociocultural aspects on past societies. The most acknowledged technique in this field is represented by minero‐petrographic analysis, allowing to describe the compositional features of the artefacts and to link them to geological outcrops and technologic processes. In the case of fine‐grained potteries, minero‐petrographic analysis might sometime give back not clear results, requiring the use of high‐resolved methods. In this framework, information about raw materials and firing techniques might be provided by the support of micro‐Raman spectroscopy, able to supply information on mineral grains not detectable under a microscope and for which powders diffraction methods are not able to provide unique interpretations. In this work, particular attention was devoted to the phases formed during the ceramic body annealing, especially to newly formed feldspars, exhibiting a not natural occurring composition. Their correct identification, important for thermometric studies, is possible only with the use different techniques, due to the different investigated aspects (structure, composition and lattice dynamics). Fine‐grained potteries from the famous site of Volterra, Tuscany (Italy) have been characterized as case study during a comparative evaluation of the results obtained by different techniques (micro‐Raman analysis, optical microscopy [OM], X‐ray diffraction [XRD] and scanning electron microscope energy dispersive spectrometry [SEM‐EDS]) on the same mineral grains. The obtained results demonstrated how micro‐Raman spectroscopy might improve interpretation of data collected with different methods in several aspects, from provenance to firing temperature estimation. [ABSTRACT FROM AUTHOR]

Organic semiconductors have been at the center of intense investigation for decades. The efficiencies of the most performing candidates, along with the compatibility with solution processing and printing led to relevant technological breakthrough. The development of market applications for Organic Light Emitting Devices (OLEDs), Organic Thin film transistors (OTFTs), and Organic Photovoltaics (OPVs) poses a relevant question regarding to the scaling up and overall sustainability of synthetic protocols employed for the preparation of active compounds. This review summarizes the role that the emerging field of micellar catalysis and surfactant enhanced chemistry can play in dramatically improving the sustainability of established and emerging performing organic semiconductors. [ABSTRACT FROM AUTHOR]

An alternating naphthalene dianhydride bithiophene copolymer (PNDAT2) is prepared by a combined direct arylation polycondensation and the latent pigment approach. PNDAT2 is the first reported example of an alternating conjugated polymer containing naphthalene dianhydride, the oxo‐analogue of naphthalene diimide often used in electron‐acceptor conjugated polymers. PNDAT2 is resistant to organic solvents and can be generated directly as film by thermal treatment of the soluble tetraester precursor PNTET2. PNDAT2 is characterized by a LUMO level of −3.9 eV, similar to that of established naphthalene diimide containing soluble copolymers. This route to insoluble electron acceptor copolymers by thermal cleavage of soluble precursors is an alternative to classical cross‐linking or orthogonal processing strategies. [ABSTRACT FROM AUTHOR]

Micellar catalysis enables carrying out Suzuki–Miyaura couplings in water under exceptionally mild conditions. Extension of such a protocol to the sustainable synthesis of highly conjugated, poorly soluble materials like [1]benzothieno[3,2-b][1]benzothiophene (BTBT) requires redesigning of the surfactants employed. The here reported new naphthalenediimide containing amphiphilic derivative, PiNap-750M, features unprecedented performances in the preparation of this and other relevant classes of organic semiconductors in water and at room temperature. [ABSTRACT FROM AUTHOR]

Recently, oxygen-equilibrated water solutions of Kolliphor EL, a well-known surfactant, have been seen to form nanomicelles with oxygen-free cores. This has prompted the successful testing of the core environment as a green medium for palladium-catalyzed Suzuki-Miyaura cross couplings. The versatility of these conditions is endorsed by several examples, including the synthesis of relevant molecular semiconductors. The reaction medium can also be recycled, opening the way for an extremely easy and green chemistry compliant methodology. [ABSTRACT FROM AUTHOR]

Sensitized triplet-triplet annihilation based photon up-conversion (TTA-UC) greatly improves the scope and applicability of fluorescence bioimaging by enabling anti-Stokes detection at low powers, thus eliminating the background autofluorescence and limiting the potential damage of the living tissues. Here the authors present a facile, one-step protocol to prepare dual dye-doped, TTA-UC active nanomicelles starting from the commercially available surfactant Kolliphor EL, a component of several FDA approved preparations. These nanosized micelles show an unprecedented up-conversion yield of 6.5% under 0.1 W cm−2 excitation intensity in an aqueous, nondeaerated dispersion. The supramolecular architecture obtained preserves the embedded dyes from oxygen quenching, allowing satisfactory anti-Stokes fluorescence imaging of 3T3 cells. This is the first example of efficient multicomponent up-converters prepared using highly biocompatible materials approved by the international authority, paving the way for the development of new complex and multifunctional materials for advanced theranostics. [ABSTRACT FROM AUTHOR]