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Abstract With drastic fossil fuel depletion and environmental deterioration concerns, a move towards a more sustainable bioenergy-based economy is essential. Lately, the application of microwave (MW) irradiation for waste processing has been attracting interest globally. MW-assisted heating possesses several advantages such as the provision of high microwave energy into dielectric materials with deeper penetration for internal heat generation, showing beneficial features in improving the heating rate and reducing the reaction time. Consequently, the most recent literature regarding the applications of MW-assisted heating for biomass pretreatment as well as biofuel and bioenergy production was reviewed and consolidated in this study. An impressive increase in the product yield and improvement of the product properties are reported, with the use of MW-assisted heating in several conversion routes to produce biofuels. Despite being a promising technology for biofuel production, some major fundamental data of MW-assisted heating have not been comprehensively identified. Therefore, the feasibility of this technology for large-scale implementation is still subpar. Understanding the interaction between the feedstock and the microwave electromagnetic field, and the optimization of several operational and mechanical parameters are the two main keystones that would propel the industrialization of MW heating in the near future. This provides key insights leading to increased feasibility and more advanced application of MW heating.

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.

An amorphous WO3 induced lattice distortion strategy leads to only 2 wt% Ir for efficient overall water splitting in acid.

Self-organizing nanopatterns can enable economically competitive, industrially applicable light-harvesting platforms for thin-film solar cells. In this work, we present transparent solar cell substrates having quasiperiodic uniaxial nanowrinkle patterns with high optical haze values. The self-organized nanowrinkle template is created by controlled heat-shrinking of metal-deposited pre-stretched polystyrene sheets. A scalable UV nanoimprinting method is used to transfer the nanopatterns to glass substrates on which single-junction hydrogenated amorphous silicon p-i-n solar cells are subsequently fabricated. The structural and optical analyses of the solar cell show that the nanowrinkle pattern is replicated throughout the solar cell structure leading to enhanced absorption of light. The efficient broadband light-trapping in the nanowrinkle solar cells results in very high 18.2 mA/cm2 short-circuit current density and 9.5% energy-conversion efficiency, which respectively are 35.8% and 39.7% higher than the values obtained in flat-substrate solar cells. The cost- and time-efficient technique introduces a promising new approach to customizable light-management strategies in thin-film solar cells.

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.

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.

We use extreme regional pollution emergencies to provide new evidence regarding the motivations for corporate social responsibility (CSR). We document that local firms strategically improve CSR to build trust following pollution emergencies, and this is specifically true for highly polluting firms. Firms face different intensities of external pressure from their stakeholders. In particular, following pollution emergencies, political dependency, institutional investors and public monitoring are the main sources of stakeholder pressure and drivers of the increased CSR. We further find that firms that gain trust through CSR activities after pollution emergencies are rewarded. CSR serves as a buffer against financial constraints, financing distress and the negative profitability effect following emergencies. This study contributes to the CSR literature on trust-building-motivated CSR strategies.