A novel configuration for high-performant perovskite/silicon tandem solar cells is demonstrated using a facile mechanical stacking of the sub-cells. The resulting champion perovskite/silicon tandem solar cell exhibits a stabilized efficiency of 25.9% over an active area of 1.43 cm 2 .

Advancements in electrochemical double-layer capacitor (EDLC) technology require the concomitant use of novel efficient electrode materials and viable electrode manufacturing methods. Cost-effectiveness, scalability and sustainability are key-drivers for fulfilling product development chain accepted by worldwide legislations. Herein, we report a scalable and sprayable "green " electrode material-based ink based on activated carbon and single-/fewlayer graphene (SLG/FLG) flakes. We show that, contrary to commercial reduced graphene oxide, defect-free and flat SLG/FLG flakes reduce the friction of ions over the electrode films, while spray coating deposition of our ink maximises the electrolyte accessibility to the electrode surface area. Sprayed SLG/FLG flakes-based EDLCs display superior rate capability performance (e.g. , specific energies of 31.5, 23.7 and 12.5 Wh kg − 1 at specific powers of 150, 7500 and 30000 W kg − 1 , respectively) compared to both SLG/FLG flakes-free devices and commercial-like EDLCs produced by slurry-coating method. The use of SLG/FLG flakes enables our sprayed EDLCs to operate in a wide range of temperature (− 40/ + 100°C) compatible with ionic liquid/organic solvent-based electrolytes, overcoming the specific power limits of AC-based EDLCs. A prototype EDLCs stack consisting of multiple large-area EDLCs, each one displaying a capacitance of 25 F, demonstrates the industrial potential of our technology.

Fluorescence based on quantum confinement is a property restricted to the nanoscopic range. The incorporation of nanoparticles in a three-dimensional polymeric network could afford macroscopic scaffolds that show nanoscopic properties. Moreover, if these scaffolds are based on strong bonds, the stability of the resulting materials can be preserved, thus enhancing their final applications. We report for the first time the preparation of a graphene quantum dot (GQD) composite based on a cationic covalent network. This new material has unusual features: (i) the final composite remains stable after several swelling-deswelling cycles, thus demonstrating strong interactions between GQDs and the polymeric material, and therefore it could be used as a portable system. (ii) Fluorescence emission in the composite and in solution is quasi-independent to the excitation wavelength. (iii) However, and in contrast to the behavior observed in GQD solutions, the fluorescence of the composite remains unaltered over a wide pH range and in the presence of different ions commonly found in tap water. (iv) Fluorescence quenching is only observed as a consequence of molecules that bear aromatic systems, and this could be applied to the preparation of in situ water sensors.

A carbon nanotube/boron nitride/rubber composite with anisotropic electrical conductivity exhibits an EMI shielding effectiveness of 22.41 dB mm−1 and a thermal conductivity equal to 0.25 W m−1 K−1.

The development of functional optoelectronic applications based on hexagonal boron nitride nanosheets (h-BNNs) relies on controlling the structural defects. The fluorescent emission, in particular, has been observed to depend on vacancies and substitutional defects. In the present work, few-layer h-BNNs have been obtained by sonication-assisted liquid-phase exfoliation of their bulk counterpart. The as-prepared samples exhibit a weak fluorescent emission in the visible range, centred around 400 nm. Tailored defects have been introduced by oxidation in air at different temperatures. A significant increase in the fluorescent emission of the oxidated h-BNNs has been observed with maximum emissive intensity for the samples treated at 300 • C. A further increase in temperatures (>300 • C) determines a quenching of the fluorescence.We investigated, by means of detailed microscopic and spectroscopic analysis, the relationship between the optical properties and defects of h-BNNs. The investigation of the optical properties as a function of treatment temperature highlights the critical role of hydroxyl groups created by the oxidation process. Only h-BN exfoliated in water allows introducing OH groups with consequent enhancement of fluorescence emission. Quantum chemical calculations support the experimental findings.

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Lithium‐sulfur batteries are the most promising candidates for next‐generation energy storage devices owing to their high theoretical specific capacity of 1675 mAh g−1 and high theoretical energy density of approximately 3500 Wh kg−1. However, the lack of cathode active materials with appropriate electrical conductivities and stability coupled with an inexpensive and industrially compatible production process has so far hindered the development of practical devices. Here, a facile preparation pathway is reported for the production of a sulfur–carbon composite active material by drying a mixture of highly conductive few‐layer graphene (FLG) flakes (produced by exploiting an innovative wet jet milling process with a yield of ≈100 % and production capability of ≈23.5 g h−1) with elemental sulfur, using ethanol as an environmentally friendly solvent. The designed sulfur–FLG composite shows excellent electrochemical results. The assembled lithium–sulfur battery exhibits a stable rate capability up to a current rate of 2C, a coulombic efficiency approaching 100 % for 300 cycles at the current rate of C/4 (420 mA g−1), and a long cycle life up to 500 cycles delivering around 600 mAh g−1 at 2C (3350 mA g−1).

A B S T R A C TWe demonstrate the large scale exfoliation of bulk black phosphorus into few-layers black phosphorus. We use wet-jet mill (WJM) as an industrially scalable exfoliation technique. In order to avoid the degradation by oxidation of the exfoliated flakes, the few-layers black phosphorus is protected by functionalisation (with 4-bromobenzene-diazonium tetrafluoroborate) during the exfoliation process. We used the exfoliated and functionalised flakes as fillers in a polymethyl methacrylate matrix to test the mechanical endurance, obtaining an improvement in the Young's modulus of 106% compared to the bare polymer. These data support the development of black phosphorus materials as 2D-polymer fillers and performance-enhancers.