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Abstract: Europium-doped La2O3 nanocrystalline powders with sizes ranging from 4nm to 300nm have been obtained by the modified Pechini, hydrothermal with conventional furnace, hydrothermal with microwave furnace, and precipitation with ultrasonic bath methods. X-ray diffraction techniques were used to study the evolution of the prepared gels towards the desired crystalline phase. We determined the size and the morphology of the nanoparticles by electronic microscopy. Finally, we studied and analyzed the luminescence properties of the trivalent europium in the hexagonal La2O3 nanocrystals by photoluminescence and cathodoluminescence. [Copyright &y& Elsevier]

In this work we study theoretically the tunability of a double-cavity Fabry–Pérot multilayer structure composed of porous silicon mirrors and liquid crystal cavities. By means of the anisotropic Transfer Matrix Method we analyze changes on wavelength and transmission of two resonant frequencies within the stop band. Tuning is achieved by allowing different orientations of the LC optical axes within the cavities, while keeping the optical axes parallel to the layers. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Comments on the influence of allusions on the intertextuality of the Latin poems by Virgil. Interpretation of author A. Traina on the word latro; Representation of the latro in the poem `Aeneid'; Views of Roman commentators on the use of latro in Virgil's poem; Implications of the poem for a game of military strategy.

The mechanisms limiting the dark current in pentacene (Pc)/C60 solar cell were determined using the temperature dependence of the current-density-voltage characteristics. Our analysis allowed us to calculate the effective barrier height for electrons and holes at the interface. We then determined the built-in potential of the heterojunction and the effective doping concentration of the active layers, using capacitance-voltage characteristics. These physical parameters were used to simulate a band-energy diagram for a Pc/C60 solar cell in equilibrium. Finally, we determined a relation between the effective barrier height and the built-in potential. [ABSTRACT FROM AUTHOR]

We present a continuous analytic current-voltage (I-V) model for cylindrical undoped (lightly doped) surrounding gate (SGT) MOSFETs. It is based on the exact solution of the Poisson's equation, and the current continuity equation without the charge-sheet approximation, allowing the inversion charge distribution in the silicon film to be adequately described. It is valid for all the operation regions (linear, saturation, subthreshold) and traces the transition between them without fitting parameters, being ideal for the kernel of SGT MOSFETs compact models. We have demonstrated that the I-V characteristics obtained by this model agree with three-dimensional numerical simulations for all ranges of gate and drain voltages. [ABSTRACT FROM AUTHOR]

We present a compact physics-based model for the nanoscale gate-all-around MOSFET working in the ballistic limit. The current through the device is obtained by means of the Landauer approach, being the barrier height the key parameter in the model. The exact solution of the Poisson's equation is obtained in order to deal with all the operation regions tracing properly the transitions between them. [ABSTRACT FROM AUTHOR]

We present a new approach for analyzing band structures in one-dimensional Kerr-nonlinear photonic crystals. It combines the finite-difference time-domain method, based on the numerical simulation of oscillating dipole radiation, with the Kerr-nonlinear model. The approach is applied to analyze the band structures in Kerr-nonlinear one-dimensional photonic crystals as a function of the intensity of the oscillating dipole. We find that these bands are dynamically red-shifted with regard to the bands in linear one-dimensional photonic crystals. The proposed approach will help to understand such phenomena as intensity-driven optical limiting and all-optical switching with Kerr-nonlinear photonic crystals. [Copyright &y& Elsevier]

Abstract: We report here the results obtained in surface ablation of RbTiOPO4 single crystals by femtosecond laser. We fabricated and characterized one-dimensional (1D) diffraction gratings with different lattice spacings of 15 and 20μm, and with a sub-modulation of the period introduced in the later. The optical and electronic microscopy characterization and filling factor analysis of these diffraction gratings are reported. We also show that the roughness generated on the grooves by the ablation process can be improved by chemical etching. [Copyright &y& Elsevier]

Abstract: Europium-doped La2O3 nanocrystalline powders with sizes in the range of 50–200nm have been obtained by the modified sol–gel Pechini method. These nanocrystals have been deagglomerated using sonication for 3h and have been dispersed into a semiconductor P3HT polymeric matrix. We studied and analysed the spectroscopic properties of the trivalent europium in the hexagonal La2O3 nanocrystals dispersed in the polymer. The luminescence spectrum of Eu3+ in these nanocrystals is dominated by the 5D0 → 7F2 transition with a maximum intensity peak located at 626nm. We observed that P3HT absorbs part of the light emitted by the nanoparticles. These properties look promising for using this material as a down-converter material in solar cells. [Copyright &y& Elsevier]

Abstract: Europium-doped La2O3 nanocrystalline powders with sizes in the range of 50–200nm have been obtained by the modified sol–gel Pechini method. Differential thermal analysis, thermogravimetric analysis, infrared spectroscopy and X-ray diffraction were used to study the evolution of the precursor powders towards the desired crystalline phase. We determined the size and the morphology of the nanoparticles by electronic microscopy. Finally, we studied and analyzed the luminescence properties of the trivalent europium in the hexagonal La2O3 nanocrystals by photoluminescence and cathodoluminescence. The luminescence spectrum of Eu3+ in these nanocrystals is dominated by the 5D0 → 7F2 transition with its maximum intensity peak located at 626nm, which makes of these nanocrystals promising nanophosphors emitting in the red region of the electromagnetic spectrum. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we study the changes in the optical properties of 300-nm-thick hydrogenated amorphous silicon carbide layers after an annealing process. Both intrinsic and phosphorus-doped amorphous silicon carbide layers (a-SiC x :H) were deposited on silicon wafers by plasma enhanced chemical vapour deposition (PECVD) at 400°C and annealed in a quartz furnace at 800°C. The presence of randomly oriented silicon nanocrystals was confirmed by X-ray diffraction (XRD) measurements after the partial recrystallization process only in the doped layers. The presence or the absence of the nanocrystals clearly changes the Fourier transform infrared (FTIR) spectra. From the fitting of the experimental curves with the model of Lorentz oscillators, the refractive index and the extinction coefficient of the different layers were obtained. [Copyright &y& Elsevier]

In this work we investigate the effects of typical thermal treatments on c-Si surface passivation by intrinsic a-SiCx:H films. First, a forming gas anneal (FGA), (400 °C, 30 min in H2/N2) is applied resulting in an improvement in surface passivation. The best result is a surface recombination velocity lower than 23 cm s−1. A second thermal step (730 °C, 30 s) is studied to try and simulate the firing step for screen-printed contacts. This annealing has no effect in surface passivation indicating that a-SiCx:H films are promising candidates for c-Si surface passivation in the photovoltaic industry. In order to analyze the improvement of surface passivation after FGA, a physical model of surface recombination at the a-SiCx:H/c-Si interface is developed. This improvement is directly connected to a reduction in fundamental recombination velocities of electrons and holes at the interface. A possible explanation could be the reduction in the interface state density due to hydrogen saturation of dangling bonds. [Copyright &y& Elsevier]

Abstract: We present the design and study of waveguide structures based on porous silicon where the light confinement is not due to the usual total reflection effect but to the use of photonic crystals (PCs) as confining walls. These PC are omnidirectional mirrors (OMs), consisting of the periodic repetition of two porous silicon layers with different refractive indices and thicknesses. They reflect the radiation for all angles of incidence within a frequency range called the omnidirectional band gap (OBG). We have followed the PC formalism to investigate the properties of the OM as a multimode waveguide: the number of modes within the band gap, their field spatial distribution and their confinement as a function of the frequency and the core thickness. [Copyright &y& Elsevier]

Introduction: Given the increasing global population of older adults, it is essential and inevitable that healthcare centers and nursing homes address and accommodate diversity in their support systems as interventions for healthy aging. The active aging and the inclusion of all people regardless of their religion, origin, and/or sexual orientation is essential to create a climate of safety. Discrimination must be addressed from all angles, at the social level, at the business level and by all workers in nursing homes., Methodology and Results: This study provides a comprehensive review of existing literature to systematize information on diversity among older adults in healthcare centers and nursing homes. Out of 1.458 articles identified, 10 were analyzed in depth, revealing that addressing diversity among older adults is crucial to overall mental and physical healthy aging. The findings underscore the need for a multidisciplinary approach and effective management through the Person-Centered Care Model (PCCM)., Discussion and Conclusion: This study highlights the critical role of the Person-Centered Care Model (PCCM) in addressing diversity in aging needs. It highlights the necessity of tailoring care based on individual life histories and experiences. Additionally, it calls for the implementation of inclusive policies in nursing homes and emphasizes the need for professional training on diversity to ensure these facilities are safe and supportive for all residents., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Mesas-Fernández, Tous-Pallarès and Espinoza-Díaz.)

Organic photovoltaic (OPV) cells have experienced significant development in the last decades after the introduction of nonfullerene acceptor molecules with top power conversion efficiencies reported over 19% and considerable versatility, for example, with application in transparent/semitransparent and flexible photovoltaics. Yet, the optimization of the operational stability continues to be a challenge. This study presents a comprehensive investigation of the use of a conjugated polyelectrolyte polymer (CPE-Na) as a hole layer (HTL) to improve the performance and longevity of OPV cells. Two different fabrication approaches were adopted: integrating CPE-Na with PEDOT:PSS to create a composite HTL and using CPE-Na as a stand-alone bilayer deposited beneath PEDOT:PSS on the ITO substrate. These configurations were compared against a reference device employing PEDOT:PSS alone, as the HTL increased efficiency and fill factor. The instruments with CPE-Na also demonstrated increased stability in the dark and under simulated operational conditions. Device-based PEDOT:PSS as an HTL reached T80 after 2500 h while involving CPE-Na in the device kept at T90 in the same period, evidenced by a reduced degradation rate. Furthermore, the impedance spectroscopy and photoinduced transient methods suggest optimized charge transfer and reduced charge carrier recombination. These findings collectively highlight the potential of CPE-Na as a HTL optimizer material for nonfluorine OPV cells.

Dairy proteins are commonly used to stabilize oil-in-water (O/W) emulsions, which can be replaced by other sustainable sources of proteins, such as insects. This study investigated the potential of lesser mealworm protein concentrate (LMPC) as a sustainable alternative to whey protein isolate (WPI) in stabilizing oil-in-water (O/W) emulsions using microfluidics. The frequency of coalescence (F coal ) was calculated using images of emulsion droplets obtained near the inlet and outlet of the coalescence channel. The stability of O/W emulsions, produced using sunflower oil (SFO) or hexadecane and stabilized with varying concentrations of LMPC and WPI (0.02% to 0.0005% w/v), was compared under controlled conditions. The dispersed phase fraction (5.3%-14.3% v/v), protein adsorption time onto oil droplets (0.0398-0.158 s), and pH (pH = 3 and pH = 7) were also studied. F coal was greatest (0.42 s -1 ) when the protein concentration was lowest (0.0005%), the oil percentage was highest (14.3%), the adsorption period was shortest (0.0398 s), and the pH was 3. Droplet diameters did not vary significantly, with values between 55 and 118 μm, across protein concentrations or adsorption periods, but a rise in oil fraction resulted in a substantial increase in droplet diameters. Increases in protein content, adsorption duration, and oil percentage all resulted in increased stability (reduction of F coal ). While LMPC and WPI showed similar results in microfluidic experiments and other test conditions, further research is needed to verify LMPC's efficacy as a replacement for WPI in food emulsification. Nonetheless, the findings suggest that LMPC has potential as a substitute for WPI in this application., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Morphological control of the layers within the bulk heterojunction organic photovoltaics (BHJ-OPVs) is a key feature that governs their performance. In the present work, we demonstrate that zinc oxide-ZnO-interlayers sprayed via the intermittent spray pyrolysis technique, employing a low-concentration precursor solution, can yield inverted BHJ-OPVs as efficient as the standard reported ones using the conventional laboratory-scale spin-coating technique. However, we record a pioneer stability behavior of the fabricated inverted fullerene organic photovoltaics (iF-OPVs) with various sprayed ZnO conditions. Thus, after optimizing the sprayed ZnO interfacial layer morphology for the inverted PTB7-Th:PC 70 BM devices, by carefully inspecting the interdependence between the sprayed ZnO thin film morphology and the figures of merit of the optimized iF-OPVs, we conducted a distinct analysis on the optical and electronic properties of the fresh and degraded devices using external quantum efficiency measurements and impedance spectroscopy. Hence, we showed that the most proper ZnO microstructural morphology was obtained by spraying 25 running cycles (25R). Remarkably, we observed that 25R-ZnO-based iF-OPV devices showed a stunning stability behavior and maintained 85% of their initial power conversion efficiency even after 16.7 months without encapsulation in a dry nitrogen glovebox, demonstrating an excellent shelf stability. Accordingly, this approach might facilitate the scalability of inverted OPVs for industrial production visibility., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Invited for this month's cover are the collaborating groups of Prof. Ángela Sastre-Santos, Universidad Miguel Hernández, Prof. Lluis F. Marsal, Universitat Rovira i Virgili and Prof. Tomás Torres, Universidad Autónoma de Madrid, Spain. The cover shows a toy doll holding an umbrella which represents a non-planar, highly conjugated subphthalocyanine-diketopyrrolopyrrole hybrid molecule for non-fullerene organic solar cells. When the sun shines on the umbrella, it absorbs the light, and the doll slides down a polymeric flexible solar cell like a slide, where electrons are produced and electricity flows into the magic wand to illuminate the room. More information can be found in the Full Paper by Ángela Sastre-Santos, Lluis F. Marsal, Tomás Torres, and co-workers., (© 2021 Wiley-VCH GmbH.)

This study analyzes experimentally the deposition of magnetic beads on the walls of a square microchannel by the action of a nearby cubical magnet. The deposition has been studied for different magnetic bead sizes, flow rates, magnetic conditions and with solutions of magnetic and non-magnetic particles. Images of the time evolution of the deposition under the different conditions have been analyzed to determine the spatial distribution of the accumulation and the growth rate of the depositions. It has been found that the way in which the magnetic beads are deposited on the walls of the microchannel depends strongly on their size and the magnetic configuration. The accumulation of the major part of particles is on the wall closest to the magnet and, depending on the size of the particles, near the magnet leading and trailing edges or near the center of the magnet. The experiments with magnetic and non-magnetic particles revealed the screening effect of the non-magnetic particles on the deposition. In this case, the non-magnetic particles displace the deposition toward the region near the center of the magnet and near the trailing edge.

Fluorinated zinc and copper metallophthalocyanines MPcF 48 are synthesized and incorporated as third component small molecules in ternary organic solar cells (TOSCs). To enable the high performance of TOSCs, maximizing short-circuit current density ( J SC ) is crucial. Ternary bulk heterojunction blends, consisting of a polymer donor PTB7-Th, fullerene acceptors PC 70 BM, and a third component MPcF 48 , are formulated to fabricate TOSCs with a device architecture of ITO/PFN/active layer/V 2 O 5 /Ag. Employing copper as metal atom substitution in the third component of TOSCs enhances J SC as a result of complementary absorption spectra in the near-infrared region. In combination with J SC enhancement, suppressed charge recombination, improved exciton dissociation and charge carrier collection efficiency, and better morphology lead to a slightly improved fill factor (FF), resulting in a 7% enhancement of PCE than those of binary OSCs. In addition to the increased PCE, the photostability of TOSCs has also been improved by the appropriate addition of CuPcF 48 . Detailed studies imply that metal atom substitution in phthalocyanines is an effective way to improve J SC , FF, and thus the performance and photostability of TOSCs., Competing Interests: The authors declare no competing financial interest., (© 2021 American Chemical Society.)

A main route for SARS-CoV-2 (severe acute respiratory syndrome coronavirus) transmission involves airborne droplets and aerosols generated when a person talks, coughs, or sneezes. The residence time and spatial extent of these virus-laden aerosols are mainly controlled by their size and the ability of the background flow to disperse them. Therefore, a better understanding of the role played by the flow driven by respiratory events is key in estimating the ability of pathogen-laden particles to spread the infection. Here, we numerically investigate the hydrodynamics produced by a violent expiratory event resembling a mild cough. Coughs can be split into an initial jet stage during which air is expelled through mouth and a dissipative phase over which turbulence intensity decays as the puff penetrates the environment. Time-varying exhaled velocity and buoyancy due to temperature differences between the cough and the ambient air affect the overall flow dynamics. The direct numerical simulation (DNS) of an idealized isolated cough is used to characterize the jet/puff dynamics using the trajectory of the leading turbulent vortex ring and extract its topology by fitting an ellipsoid to the exhaled fluid contour. The three-dimensional structure of the simulated cough shows that the assumption of a spheroidal puff front fails to capture the observed ellipsoidal shape. Numerical results suggest that, although analytical models provide reasonable estimates of the distance traveled by the puff, trajectory predictions exhibit larger deviations from the DNS. The fully resolved hydrodynamics presented here can be used to inform new analytical models, leading to improved prediction of cough-induced pathogen-laden aerosol dispersion., (© 2021 Author(s).)

Airborne particles are a major route for transmission of COVID-19 and many other infectious diseases. When a person talks, sings, coughs, or sneezes, nasal and throat secretions are spewed into the air. After a short initial fragmentation stage, the expelled material is mostly composed of spherical particles of different sizes. While the dynamics of the largest droplets are dominated by gravitational effects, the smaller aerosol particles, mostly transported by means of hydrodynamic drag, form clouds that can remain afloat for long times. In subsaturated air environments, the dependence of pathogen-laden particle dispersion on their size is complicated due to evaporation of the aqueous fraction. Particle dynamics can significantly change when ambient conditions favor rapid evaporation rates that result in a transition from buoyancy-to-drag dominated dispersion regimes. To investigate the effect of particle size and evaporation on pathogen-laden cloud evolution, a direct numerical simulation of a mild cough was coupled with an evaporative Lagrangian particle advection model. The results suggest that while the dispersion of cough particles in the tails of the size distribution are unlikely to be disrupted by evaporative effects, preferential aerosol diameters (30-40  μ m) may exhibit significant increases in the residence time and horizontal range under typical ambient conditions. Using estimations of the viral concentration in the spewed fluid and the number of ejected particles in a typical respiratory event, we obtained a map of viral load per volume of air at the end of the cough and the number of virus copies per inhalation in the emitter vicinity., (© 2021 Author(s).)