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The optical and photovoltaic properties of Si NCs / SiC multilayers (MLs) are investigated using a membrane-based solar cell structure. By removing the Si substrate in the active cell area, the MLs are studied without any bulk Si substrate contribution. The occurrence is confirmed by scanning electron microscopy and light-beam induced current mapping . Optical characterization combined with simulations allows us to determine the absorption within the ML absorber layer, isolated from the other cell stack layers. The results indicate that the absorption at wavelengths longer than 800 nm is only due to the SiC matrix. The measured short-circuit current is significantly lower than that theoretically obtained from absorption within the ML absorber, which is ascribed to losses that limit carrier extraction. The origin of these losses is discussed in terms of the material regions where recombination takes place. Our results indicate that carrier extraction is most efficient from the Si NCs themselves, whereas recombination is strongest in SiC and residual a-Si domains . Together with the observed onset of the external quantum efficiency (EQE) at 700-800 nm, this fact is an evidence of quantum confinement in Si NCs embedded in SiC on device level.

Industrial heat and cooling applications are an essential fraction of the overall energy demand, mainly produced by fossil fuels. Solar thermal energy production can satisfy such a need by adopting the High Vacuum Flat Plate Collectors (HVFPCs) and increasing their efficiency. The absorptance and emittance of Selective Solar Absorbers (SSAs) determine the thermal efficiency of HVFPCs. Being the absorptance already maximized, the thermal emittance of the absorber should be minimized to increase further the operating temperature of the collector and its efficiency. This research aims to reduce the thermal emittance of commercially available Selective Solar Absorber by depositing a thin silver film on the aluminium substrate. So, in this work, the thermal stability of a silver coating has been investigated, and a diffusion barrier layer has been adopted to stabilize the coating performance up to 360 degrees C. The low-emissive layer of Ag and a diffusion barrier of CrOx guarantees a decrease of 11% in thermal emittance at 200 degrees C of commercially available SSA deposited on aluminium. Further emittance reduction can be obtained by depositing a thin Ag film on both sides of the aluminium substrate before the SSA deposition, proving to be a promising way to enhance the efficiency of HVFPCs.

The use of graphene as transparent conducting layer in devices that require high temperature processing is proposed. The material shows stability upon thermal treatments up to 1100 °C ifc apped with a sacrificial silicon layer. The use of Cu foil or evaporated Cu as catalysts in Catalytic-Chemical Vapor Deposition growth gives rise to graphene ofs imilar properties, which represents a promising result in view of its direct integration in microelectronic devices. Photovoltaic p-i-n thin film devices were fab- ricated on the as-deposited or annealed graphene membranes and compared with similar devices that incorporate as-deposited Indium Tin Oxide. No degradation in series resistance is observed for the annealed device. A 3.7% and 2.8% photovoltaic conversion efficiency is observed on the devices fabricated on as-transferred and on annealed graphene respectively. The major limitation derives from the high sheet resistance of the as-transferred state-of-the-art material. The results opens the way to the use of graphene in applications that require transparent conducting layers resistant to high temperature pro- cessing.

Digestates from low-tech digesters need to be post-treated to ensure their safe agricultural reuse. This study evaluated, for the first time, vermifiltration as a post-treatment for the digestate from a low-tech digester implemented in a small-scale farm, treating cattle manure and cheese whey under psychrophilic conditions. Vermifiltration performance was monitored in terms of solids, organic matter, nutrients, and pathogens removal efficiency. In addition, the growth of earthworms (Eisenia foetida) and their role in the process was evaluated. Finally, the vermicompost and the effluent of the vermifilter were characterized in order to assess their potential reuse in agriculture. Vermifilters showed high removal efficiency of chemical oxygen demand (55-90%), total solids (60-80%), ammonium nitrogen (83-97%), and phosphate-P (28-49%). Earthworms effectively grew and reproduced on digestate (i.e. earthworms number increased by 183%), enhancing the vermifiltration performance, while reducing clogging and odour-related issues. Both the vermicompost and effluent produced complied with legislation limits established for soil improvers and wastewater for fertigation, respectively. Indeed, there was an absence of pathogens and non-detectable heavy metals concentrations. Vermifiltration may be thus considered a suitable post-treatment option for the digestate from low-tech digesters, allowing for its safe agricultural reuse and boosting the circular bioeconomy in small-scale farms.

Power system controls are vulnerable to cyber-attacks that can seriously affect and even inhibit their operation. Such attacks may affect large portions of the power system, make repair difficult and cause huge societal impact, so pressure to ensure cyber-security of control and communication systems is now strong worldwide. Several cyber-security frameworks were developed, but it is rather difficult to anticipate adoption costs and benefits, and this hampers their generalised adoption. T his paper focuses on the outcome of two case studies (concerning the Italian power generation and the Polish transmission systems. The socio-economic impact of failures and the costs of standard adoption are estimated on an objective basis. It is up to public authorities to decide whether to require the adoption of security standards to operators in the electric system. The nature of public good of security underlines the necessity of public support for this operation, but we discuss the extent and the management of this support.

Ammonia is a promising clean and sustainable energy carrier, yet challenges persist in achieving stable combustion, particularly concerning poor ignition quality and elevated NOx emissions. Recent research suggests that the Moderate or Intense Low-oxygen Dilution (MILD) regime could address these challenges for ammonia combustion. This study aims to optimize the MILD regime using non-equilibrium plasma discharges, specifically nanosecond repetitive pulsed discharges (NRPD). While the beneficial effects of NRPD on ammonia chemistry have been demonstrated in traditional applications, their impact under the highly diluted conditions characteristic of the MILD regime remains unexplored. This numerical study employs a detailed two-temperature model to investigate the effects of pulsed discharges in ammonia/air mixtures, simulating conditions representative of the MILD regime. The research comprehensively explores the selection of optimal discharge settings and examines plasma effects on various parameters, including ignition delay time, flammability limit, radical production, and emissions. Equivalence ratios ranging from 0.2 to 2 and dilution levels up to 2.5% O2 are considered in this investigation. Results indicate that NRPD show a notable benefit by enlarging fuel-lean and fuel-rich stability limits, promising enhanced operational flexibility. Examining OH radicals and NOx emissions underscored a consistent plasma-driven mechanism, reducing emissions, also in the MILD regime. Novelty and Significance Statement The novelty of this research is the application of non-equilibrium plasma discharges to improve ammonia combustion in the MILD regime. It offers a new and original solution to the challenges associated with the poor ignition quality and high NOx emissions that are currently limiting its practical implementation. For the first time, a numerical analysis is provided to quantify the benefits of plasma chemistry activation on the combustion performance. Another novel aspect of this work is the use of a detailed two-temperature model to describe the plasma-combustion interactions in an integrated computational framework. The literature reports only a few references on the interaction of plasma with MILD combustion conditions. The former were modeled using a very simplified model to describe the evolution of the plasma species. Consequently, we believe that this contribution will significantly advance the state-of-the-science in field of plasma-assisted ammonia combustion.

Silicon carbide/silicon rich carbide multilayers, aimed at the formation of silicon nanodots for photovoltaic applications, have been studied. The electrical properties have been investigated at the nano-scale by conductive Atomic Force Microscopy (c-AFM) and at macro-scale by temperature dependent conductivity measurements. The mixture is composed of highly conductive Si nanoclusters and moderately conductive SiC nanoclusters in a disordered matrix. The conduction mechanism takes place via band states induced by the disorder at the interface between nanodot clusters. Structural properties have been extracted by optical spectroscopy analyses. The results contribute to the understanding of the microscopical electronic mechanisms of the composite material, which is a candidate for third generation photovoltaics.

The unique properties of per- and polyfluoroalkyl substances (PFAS) have driven their pervasive use in different industrial applications, leading to substantial environmental pollution and raising critical concerns about the long-term impacts on ecosystem and human health. To tackle the global challenge of PFAS contamination, there is an urgent need for sustainable and efficient remediation strategies. Phytoremediation has emerged as a promising eco-friendly approach with the potential to mitigate the spread of these persistent contaminants. However, addressing this complex issue requires interdisciplinary cutting-edge research to develop comprehensive and scalable solutions for effective PFAS management. This review highlights recent advancements in the detection, quantification, and monitoring of PFAS uptake by plants, providing a detailed description of PFAS accumulation in several plant species. Besides, the physiological and molecular responses elicited by these pollutants are described. Leveraging omic technologies, including genomics, transcriptomics, and proteomics, provides unprecedented insights into the plant-PFAS interaction. Novel approaches based on artificial intelligence to predict this interaction and up to date disposal and valorization methods for PFAS-contaminated plant biomass, are discussed here. This review offers an interdisciplinary approach to explore what has been discovered so far about PFAS phytoremediation, covering the entire process from contaminant uptake to sustainable disposal, providing a roadmap for future research.