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The donor/acceptor inter-mixing in bulk heterojunction (BHJ) solar cells is a critical parameter, often leading to irreproducible performance of the finished device. An alternative solution-processed device fabrication strategy towards a better control of the micro/nano-structured morphology consists of a sequential coating of the donor (e.g., poly-(3-hexylthiophene), P3HT) and the acceptor (e.g., [6,6]-phenyl-C61-butyric acid methyl ester, PCBM) from orthogonal solvents. We demonstrate that, in spite of the solvent orthogonality, this technique does not lead to a well-defined bilayer with a sharp interface, but it rather results in a graded vertical phase-separated junction, resulting from the diffusion of the PCBM in the P3HT bottom layer. We are able to control the diffusion of PCBM, which occurs preferentially in the amorphous P3HT domains, by easily varying the ratio between crystalline/amorphous domains in the P3HT. Such a ratio can be simply modified by changing the solvent for P3HT. We show that the donor–acceptor diffused bilayer (DB) junction is an intermediate structure which combines both advantages of the well-defined bilayer and conventional BHJ configurations. Indeed, the DB device geometry ensures the good reproducibility and charge percolation, like the well-defined bilayer, while preserving the interpenetration of the donor and acceptor species, resulting in an efficient charge separation, characteristic of the BHJ. Overall the annealed DB device geometry can be assimilated to a graded BHJ with an improved reproducibility and mean power conversion efficiency (PCE) of 3.45%, higher than that of the standard BHJ devices of 3.07%. Furthermore, we demonstrate the highest performance for the as-cast DB device with a PCE of 2.58%. It is worthy to note that our DB device exhibits improved open circuit voltage, fill factor, series and shunt resistances, which denote that the vertically phase separated DB junction ensures improved charge percolation.

The extra-tropical atmosphere is characterized by robust cir- culations which have time scales longer than that associated with develop- ing baroclinic systems but shorter than a season. Such low frequency vari- ability is governed to a large extent by non-linear dynamics, and hence is chaotic. A useful aspect of this low-frequency circulation is that it can often be de- scribed by just a few quasi-stationary regime states, broadly defined as re- current or persistent large scale structures, that exert a significant impact on the probability of experiencing extreme surface weather conditions. We review a variety of techniques for identifying circulation regimes from reanalysis and numerical model output. While various techniques often yield similar regime circulation patterns, they o?er di?erent perspectives on the regimes. The regimes themselves are manifest in planetary scale patterns. They a?ect the structure of synoptic scale patterns. Extra-tropical flow regimes have been identified in simplified atmospheric models and comprehensive coupled climate models and in reanalysis data sets. It is an ongoing challenge to accurately model these regime states and high horizontal resolutions are often needed to accurately reproduce them. The regime paradigm helps to understand the response to external forcing

Cultural heritage (CH) is considered a key element of cities and regions’ identity anduniqueness, contributing to people's wellbeing and health, as well as jobs creation, environmentalregeneration and place attractiveness. The adaptive reuse of abandoned and underused CH can be asustainable strategy for heritage conservation, stimulating local development processes. However,heritage conservation needs large investments, while the resources available are scarce, and invest-ment projects are subject to high uncertainties. Therefore, a careful assessment of impacts is neededto orient and direct CH adaptive reuse projects towards sustainability. Recent studies approach theadaptive reuse of abandoned buildings and sites as an effective circular economy strategy, potentiallycontributing to climate objectives through environmental regeneration and the reduction of naturalresources consumption. However, evaluation tools to assess the impacts and orient adaptive reuseinterventions in the perspective of circularity are lacking. Through the analysis of 76 literature sourceson CH impacts, this article explores how indicators are currently used in CH research and practice asimpact assessment tools. More than 3500 indicators were retrieved and classified. Finally, this articleproposes a comprehensive evaluation framework to assess the impacts of cultural heritage adaptivereuse in the perspective of the circular economy. The results show that, while some indicators areavailable, many circularity aspects are not considered in the current studies on CH impacts.

Dielectric microspacers (DMS) are a novel micro-technology that can be used to achieve a fixed micron/sub-micron gap distance between two separated surfaces, such as the emitter (cathode) and the PV cell (anode) of a near-field thermophotovoltaic converter (TPV). One of the system’s challenges is the flow of undesirable excess thermal energy from the cathode to the anode that might cause the PV cell to overheat. This work investigates the possibility of integrating this technology into a hybrid thermionic-photovoltaic (TIPV) converter operating at ultra-high temperatures (>1000 °C) without any risk of collector’s overheating, which might lead to its mechanical failure. A steady-state 3-D CFD model was developed in Fluent v17.1 solver to assess the system’s thermal behavior when the two electrodes were separated by a distance of 8–10 μm. The heat transfer through conduction across the system components and the net photon/electron flux between the two electrodes were simulated. Different cathode temperatures within the range of 1500–2500 K and various DMS shapes (capillary, cylindrical), patterns (e.g., ring-shaped) and sizes were studied. Results show that thermal performance is not affected by the DMS pattern, even for thermal conductivities of 80 W/(m·K), whereas the possibility of mechanical failure is considerable for Tcathode > 2000 K.

A clear gap was identified in the literature regarding the in-depth evaluation of scaling up thermal energy storage components. To cover such a gap, a new methodological approach was developed and applied to a novel latent thermal energy storage module. The purpose of this paper is to identify some key aspects to be considered when scaling up the module from lab-scale to full-scale using different performance indicators calculated in both charge and discharge. Different normalization methods were applied to allow an appropriate comparison of the results at both scales. As a result of the scaling up, the theoretical energy storage capacity increases by 52% and 145%, the average charging power increases by 21% and 94%, while the average discharging power decreases by 16% but increases by 36% when mass and volume normalization methods are used, respectively. When normalization by the surface area of heat transfer is used, all of the above performance indicators decrease, especially the average discharging power, which decreases by 49%. Moreover, energy performance in charge and discharge decreases by 17% and 15%, respectively. However, efficiencies related to charging, discharging, and round-trip processes are practically not affected by the scaling up.

Pre-plasma mobilization of magnetic dust can be an important issue for future fusion reactors where plasma breakdown is critical. A combined on-line and off-line study of magnetic dust in ASDEX Upgrade is reported. Post-mortem collection revealed similar composition and morphology compared to other tokamaks, but the overall amount was much smaller. Optical and IR camera diagnostics excluded dust flybys prior to plasma start-up. The negative detection is discussed in light of the magnetic dust properties, the strength of mobilizing forces and the temporal evolution of the magnetic field.

This paper presents an experimental and theoretical study on the impact of doping and recombination mechanisms on quantum dot solar cells based on the InAs/GaAs system. Numerical simulations are built on a hybrid approach that includes the quantum features of the charge transfer processes between the nanostructured material and the bulk host material in a classical transport model of the macroscopic continuum. This allows gaining a detailed understanding of the several physical mechanisms affecting the photovoltaic conversion efficiency and provides a quantitatively accurate picture of real devices at a reasonable computational cost. Experimental results demonstrate that QD doping provides a remarkable increase of the solar cell open-circuit voltage, which is explained by the numerical simulations as the result of reduced recombination loss through quantum dots and defects.