Artículos (Física Aplicada I)

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Incorporating radioactive decay chains within Lagrangian marine radionuclide transport models for assessing the consequences of nuclear accidents
(MDPI, 2026-02-08) Cortés Parejo, María del Carmen; Periáñez Rodríguez, Raúl; Matemática Aplicada I; Física Aplicada I; FQM164: Matemática Discreta: Teoría de Grafos y Geometría Computacional; RNM138: Física Nuclear Aplicada
Lagrangian particle-tracking models are increasingly used to simulate radionuclide transport in marine environments, especially for assessing the consequences of accidental releases. However, existing models generally neglect radioactive decay chains, limiting their ability to reproduce the complete behavior of radionuclides and their progeny. To the authors’ knowledge, this work presents the first implementation of radioactive decay chains within a fully three-dimensional Lagrangian marine radionuclide transport model, explicitly coupling stochastic particle tracking with decay kinetics and dynamic sediment–water interactions, enabling a realistic simulation of parent–daughter transformations in the ocean. The approach is tested for the chain in the Western Mediterranean Sea, following a hypothetical nuclear accident. Results confirm that the stochastic treatment accurately reproduces analytical decay solutions and can be seamlessly incorporated into operational-scale transport simulations. The framework can be extended to other radionuclide series and marine domains, providing a versatile and computationally efficient tool for emergency response, environmental impact assessment, and safety analysis in nuclear engineering applications.
How the absorber thickness affects the electrical and structural properties of Sb2Se3 solar cells
(Elsevier, 2026-05) Torabi, Narges; Delgado Sánchez, José María; Artegiani, Elisa; Kuliček, Jaroslav; Rezek, Bohuslav; Jakuza, Paola; Meneghini, Matteo; Romeo, Alessandro; Física Aplicada I; European Cooperation in Science and Technology (COST); Ministry of Education, Youth, and Sports (MEYS); TEP122: termodinámica y Energías Renovables
This work investigates how the absorber thickness and a mild post-annealing treatment (PAT) in air jointly affect the structural and electrical properties of thermally evaporated Sb2Se3 absorbers, and the performance of superstrate solar cells. Sb2Se3 layers with thicknesses of 400, 800, and 1200 nm were deposited on a CdSe buffer and integrated in glass/SnO2:F/SnO2/CdSe/Sb2Se3/Au devices. Contrary to the usual expectation for thin-film absorbers, the thinnest device (400 nm) yields the highest power conversion efficiency (PCE), increasing from 2.8 % to 3.7 % after annealing in air, while thicker absorbers (800 and 1200 nm) only reach 3.5 % and 3.3 %, respectively. These trends correlate with a higher hole concentration (≈4.6 × 1016 cm−3 before PAT and ≈1.3 × 1017 cm−3 after PAT) and reduced defect density in the thinnest absorber, as revealed by CV/DLCP analysis, which also shows a narrowing of the space-charge region that favors carrier collection in ultra-thin devices. Morphological and XRD analyses confirm conventional grain growth and only subtle changes in crystal orientation with thickness and annealing, indicating that microstructural evolution alone does not govern the efficiency trends. Instead, SIMS profiles show oxygen incorporation throughout the absorber after PAT, while PL measurements and the convergence of CV and DLCP profiles demonstrate suppression of deep defects. These observations point to oxygen-induced passivation of electrically active defects as the main mechanism behind the improved open-circuit voltage and fill factor. Overall, the results highlight that in Sb2Se3/CdSe solar cells with very high absorption coefficients, carrier transport, defect passivation, and space-charge region engineering are more critical than increasing the absorber thickness, enabling efficient devices with ultra-thin (400 nm) Sb2Se3 absorbers.
Modelling the accumulation of 137Cs by Atlantic bluefin tuna (Thunnus thynnus) after a hypothetical nuclear accident in the Northwest Atlantic Ocean
(Elsevier, 2026-01) Cortés Parejo, María del Carmen; Periáñez Rodríguez, Raúl; Block, Barbara A.; Castleton, Michael R.; Cermeño Villanueva, Pablo; Dedman, Simon; Matemática Aplicada I; Física Aplicada I; FQM164: Matemática Discreta: Teoría de Grafos y Geometría Computacional; RNM138: Física Nuclear Aplicada
The potential accumulation of radionuclides in migratory fish following nuclear accidents is a concern for marine ecology and human consumption. We developed and applied a Lagrangian numerical model coupled with a four-level food web uptake module to simulate the transport and bioaccumulation of 137Cs in Atlantic bluefin tuna (Thunnus thynnus) in the Northwest Atlantic Ocean, following hypothetical Fukushima-like releases from three coastal nuclear power plants in eastern North America. Tuna trajectories were obtained from electronic tagging data, and 137Cs transfers from water and prey were modelled daily at each tuna location. Simulations show that even when tuna pass through contaminated water and food patches, the resulting 137Cs concentrations in their flesh remain low, with maximum values around 1 Bq/kg wet weight. These concentrations are well below international safety limits and often below typical background levels. The study confirms that the rapid movement of migratory species limits radionuclide uptake, suggesting that tuna consumption would remain safe even in the event of such accidents.
Feasibility of a new GRT setup for the analysis of quaternary metal alloys with radioactive gamma sources
(Elsevier, 2025-11) Moreno-Soto, Javier; Ager Vázquez, Francisco José; Paúl Escolano, Antonio; Gómez Tubío, Blanca; Ortega-Feliú, Inés; Ferreti, Marco; Respaldiza Galisteo, Miguel Ángel; Física Aplicada I; Ingeniería y Ciencia de los Materiales y del Transporte; Física Aplicada III; Física Atómica, Molecular y Nuclear; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; European Union (UE); RNM138: Física Nuclear Aplicada; TEP973: Tecnología de Polvos y Corrosión
Analysing archaeological artefacts made from metallic alloys is often challenging due to the impracticality of sample collection. Traditional non-invasive surface techniques, such as X-ray fluorescence (XRF), electron probe microanalysis (EPMA), scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), and particle-induced X-ray emission (PIXE), among others, may yield misleading results if the objects are affected by corrosion or enrichment effects. Consequently, these techniques need to be complemented with others to gain a precise understanding of alloy composition. Gamma-ray transmission (GRT) is a non-destructive technique that can reveal the bulk composition of a sample. A new GRT setup has been developed to measure the concentrations of binary, ternary, and quaternary alloys using three sources simultaneously, reducing the measurement time. Alloys made in the laboratory were analysed with XRF, showing notable composition discrepancies in some cases, while the GRT results agreed with the expected composition. This innovative GRT setup, with its potential to significantly contribute to future archaeological investigations of alloy compositions, proves to be a valuable tool for analysing metallic artefacts.
Bimetallic Ru/Co nanoparticles stabilized by N-heterocyclic carbenes as catalysts for H/D exchange in N-heterocycles with deuterium gas
(Royal Society of Chemistry (RSC), 2025) Molinillo, Pablo; Gálvez Del Postigo, Ana; Puyo, Maxime; Vattier Lagarrigue, María Florencia; Lacroix, Bertrand; Rendón Márquez, Nuria; Lara Muñoz, Patricia; Suárez, Andrés; Química Inorgánica; Física Aplicada I; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España
A series of bimetallic ruthenium/cobalt nanoparticles (RuCo·IMes) stabilized with a N-heterocyclic carbene ligand, 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMes), was prepared through co-decomposition of the Ru(COD)(COT) (COD = 1,5-cyclooctadiene; COT = 1,3,5-cyclooctatriene) and Co(COD)(η3-cyclooctenyl) precursors with H2 (3 bar) using ligand/metal ratios of 0.2. The resulting nanoparticles, which exhibit mean sizes between 1.1 and 1.6 nm, were characterized using (high) transmission electron microscopy (TEM, HRTEM), inductively coupled plasma (ICP) analysis and X-ray photoelectron spectroscopy (XPS). Particularly, XPS measurements support the presence of both Co and Ru atoms on the nanoparticle surfaces and the coordination of the IMes ligand. Finally, the RuCo·IMes nanoparticles were applied to the hydrogen isotope exchange (HIE) reactions with deuterium gas (D2) in N-heterocycles. The catalytic activity and deuterium incorporation selectivity of the RuCo·IMes nanoparticles were found to strongly depend on the specific substrate examined, generally providing lower activities and slightly higher selectivities with the presence of increasing amounts of Co in the nanoparticles.
Accurate Full-Wave Bloch Analysis of General 1D-Periodic Open Structures
(Institute of Electrical and Electronics Engineers, 2025-07-16) García Martínez, S.; Giusti, Federico; Mesa Ledesma, Francisco Luis; Tamayo-Domínguez, Adrián; Quevedo Teruel, Óscar; Física Aplicada I; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); TIC112: Microondas
This article explores and validates the effectiveness of the multimodal transfer-matrix method (MMTMM) for accurate Bloch analysis of generic 1D-periodic leaky-wave structures. The method offers a systematic methodology for computing the complex wavenumbers of both proper and improper leaky modes by using the multimodal transfer matrix of a single unit cell, which can be obtained with commercial software. The versatility and accuracy of the MMTMM are first validated for rectangular waveguides loaded with periodic slots, where the leaky mode arises as a perturbation of the fundamental waveguide mode. Its applicability is further demonstrated for more complex surface-wave-supporting periodic structures commonly used in leaky-wave antennas (LWAs), including corrugated surfaces and grounded-dielectric strip gratings. The results are verified against ad hoc solutions using the method of moments (MoM). The reliability of the method is demonstrated by the convergence of the solutions from multiple simulations. The MMTMM proves to be an efficient, accurate, and reliable means of obtaining the leakage constant and phase shift of general 1D-periodic open structures.
Accurate Ray-Tracing Modeling of Radiation From Leaky-Wave Antennas
(Institute of Electrical and Electronics Engineers, 2025-09-08) Poveda García, Miguel; Mesa Ledesma, Francisco Luis; Gómez Tornero, José Luis; Quevedo Teruel, Óscar; Algaba Brazalez, Astrid; Electrónica y Electromagnetismo; Física Aplicada I; Ministerio de Ciencia e Innovación (MICIN). España; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Gobierno de España; TIC112: Microondas
In this letter, we propose the use of a radial ray-tracing approach to accurately model the radiation from leaky-wave antennas (LWAs). The technique involves the launching of several sets of rays that emanate radially from different source points along the LWA aperture. The trajectory of the emitted rays is determined and applied to accurately evaluate the impact of every source point on the radiation pattern of the LWA, with particular attention to complex setups incorporating dielectric lenses. Each source point’s contribution is superimposed, weighted by a complex factor related to the LWA’s leaky mode. The method demonstrates both efficiency and accuracy in modeling radiation patterns for different taperings of the leaky mode used to generate shaped beams, leading to a significant reduction in computation time compared to commercial full-wave solvers.
Design of Broadband Aperture-Stacked Patch Microstrip Antennas Based on Third Order Filtering Equivalent Circuits
(Institute of Electrical and Electronics Engineers, 2025-12-05) Delgado Lozano, Ignacio María; Rodríguez Boix, Rafael; Losada Torres, Vicente; Fernández Prieto, Armando; Electrónica y Electromagnetismo; Física Aplicada I; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); TIC112: Microondas
In this paper the authors describe the design of a broadband aperture-stacked patch (ASP) microstrip antenna based on a filtering equivalent circuit. The antenna consists of two stacked microstrip patches that are fed by a microstrip line through a resonant aperture. An equivalent circuit is proposed for the antenna consisting of three LC parallel resonators, out of which two resonators are inductively coupled and two resonators are capacitively coupled. The equivalent circuit is de-embedded from the antenna response by means of the least squares method, and the dimensions of the antenna are adjusted in such a way their equivalent circuit matches the response of a broadband third order filter. The reference filter is used as a mean to ensure broadband matching of the antenna. Following this design strategy, a broadband ASP antenna has been designed, fabricated and measured at a center frequency of 5.5 GHz with a bandwidth of roughly 45%.
On the Brillouin Zones of Glide-Symmetric Structures
(Institute of Electrical and Electronics Engineers, 2025-12-11) Petek, Martin; Tobón Vásquez, Jorge Alberto; Valerio, Guido; Mesa Ledesma, Francisco Luis; Quevedo Teruel, Óscar; Vipiana, Francesca; Física Aplicada I; TIC112: Microondas
In this work, we investigate the appropriate definitions of the Brillouin zones and unit cells for glide-symmetric structures. In addition to translational periodicity, such structures possess glide symmetry; that is, invariance after a translation and a mirroring. Starting from basic concepts, we show that defining glide-symmetric structures only by their translational periodicity leads to dispersion diagrams that are less clear and practical, similar to the effect observed when unnecessarily large periods are employed. In particular, we observe that the anisotropy of the structure is incorrectly assessed when following the definitions commonly adopted in the existing literature. Therefore, we introduce a modeling technique utilizing the multi-modal transfer matrix method. This method can incorporate glide-periodicity effectively, leading to an efficient solution as it operates with a reduced computational domain. It also leads to the demonstration of the effects of misleading definitions on various commonly used geometric configurations in the literature. The framework described here is applicable to any glide-symmetric structure and facilitates the comparison of different types of unit cells.
Stable bi-frequency spinor modes as Dark Matter candidates
(Springer, 2025-10-10) Comech, Andrew; Kulkarni, Niranjana; Boussaïd, Nabile; Cuevas-Maraver, Jesús; Física Aplicada I; Ministerio de Ciencia e Innovación (MICIN). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); FQM280: Física no Lineal
We show that spinor systems with scalar self-interaction, such as the Dirac-Klein-Gordon system with Yukawa coupling or the Soler model, generically have bi-frequency solitary wave solutions. We develop the approach to stability properties of such waves and use the radial reduction to show that indeed the (linear) stability is available for a wide range of parameters. We show that only bi-frequency modes can be dynamically stable and suggest that stable bi-frequency modes can serve as storages of the Dark Matter. The approach is based on linear stability results of one-frequency solitary waves in (3+1)D Soler model, which we obtain as a by-product.
Glide-shifted dielectric gratings for independent leakage and phase tuning in leaky-wave antennas
(Institute of Electrical and Electronics Engineers, 2025-10) Tomic, Dubravko; Mesa Ledesma, Francisco Luis; Sipus, Zvonimir; Física Aplicada I; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); TIC112: Microondas
This paper presents a comprehensive analysis of grounded glide-shifted dielectric periodic structures and their application to the design of leaky-wave antennas (LWAs). A modified Rigorous Coupled Wave Analysis (RCWA) framework has been developed to calculate the dispersion characteristics of these periodic structures (containing glide-shifted layers) and decrease the computational complexity. A method for solving the derived dispersion equation is discussed that enables differentiation between proper and improper radiating modes. The proposed unit cell geometry, featuring a grounded two-layer dielectric grating (identical gratings with glide-shift between them) demonstrates intriguing dispersion characteristics governed by the ratio of the thicknesses of the two layers. These characteristics include the first stopband closure and the possibility of precise control over the leakage rate while maintaining minimal variation in the phase constant. Numerical validation using the Legume-GME package and CST Eigenmode Solver confirms the accuracy of the method. Building on this analysis, the framework is applied to design LWAs with tapered aperture illumination, with a dielectric Mikaelian lens used as a surface wave launcher. This work underscores the critical role of glide symmetry and analytical modeling in advancing periodic structures, with LWAs emerging as a practical outcome for tailored microwave and millimeter-wave applications.
Enhanced Luminous Transmission and Solar Modulation in Thermochromic VO2Aerogel-like Films via Remote Plasma Deposition
(American Chemical Society, 2025-09-22) Obrero, José Manuel; Moreno Martínez, Gloria P.; Rojas Ruiz, Teresa Cristina; Ferrer Fernández, Francisco Javier; Moscoso, Francisco G.; Contreras-Bernal, Lidia; Castillo Seoane, Javier; Núñez Gálvez, Fernando; Aparicio Rebollo, Francisco Javier; Borrás Martos, Ana Isabel; Sánchez Valencia, Juan Ramón; Barranco Quero, Ángel; Física Atómica, Molecular y Nuclear; Química Física; Física Aplicada I; Ministerio de Ciencia e Innovación (MICIN). España; European Union (UE); Junta de Andalucía; Consejo Superior de Investigaciones Científicas (CSIC)
Vanadium dioxide (VO2) is a thermochromic material that undergoes a phase transition from a monoclinic semiconducting state to a rutile metallic state at 68 °C, a temperature close to room temperature. This property makes VO2 particularly valuable in applications such as optical and electrical switches, data storage, neuromorphic computing, and remarkably dynamic smart windows for solar radiation control. VO2 typically needs to be synthesized for these applications as nanostructured thin films. Over the past few decades, significant efforts have been made to control the thermochromic properties of VO2 through crystal structure tuning, doping, and the development of VO2 nanocomposites. Additionally, introducing nano- and mesoporosity has been shown to enhance the optical properties of thermochromic VO2 films. This study presents a methodology for producing highly porous, aerogel-like V2O5 films, which can be thermally processed to form aerogel-like VO2 films. This process is based on sequential plasma polymerization and plasma etching to produce aerogel-like V2O5 films that are annealed to yield ultraporous nanocrystalline VO2 films. The sacrificial vanadium-containing plasma polymers are obtained by remote plasma-assisted vacuum deposition (RPAVD) using vanadyl porphyrin as a precursor and Ar as plasma gas. Additional reference compact films VO2 films are obtained by a direct RPAVD process using the same precursor and oxygen plasmas in combination with thermal annealing. The aerogel-like VO2 films show exceptional thermochromic performance with luminous transmittances higher than 54%, solar modulation up to 18.8%, and IR modulation up to 35.5%. The presented plasma methodology is versatile, allowing both the synthesis of VO2 plasmonic structures to enhance the thermochromic response and the encapsulation of films to improve their stability in air dramatically. Additionally, this solvent-free synthetic method is fully compatible with doping procedures, scalable, and holds great potential for designing and optimizing smart window coatings.
Memory effects in a vibrated thin granular layer
(EDP Sciences, 2025-12-01) Vega Reyes, Francisco; Rodríguez Rivas, Álvaro; García de Soria Lucena, María Isabel; Maynar Blanco, Pablo; Física Atómica, Molecular y Nuclear; Matemática Aplicada II; Física Aplicada I
We present in this work the first experimental evidence of the termal memory effect in agran-ular fluid. In particular, we observe here the Kovacs memory effect (an anomalous evolution of at least one macroscopic variable) in the granular temperatura of the fluidized granular monolayer. The experimental set-up consists here in a vertically shaken granular monolayer. The evolution of the granular temperatura curves clearly displays the characteristic Kovacs humps. Furthermore, it appears that, at experimental level, the shaken monolayer displays the so-called anomalous Kovacs effec; i. e., and upwards hump for cool down protocol (or a downwards hump for a heating up process). The experimental results are also supported by molecular dynamics simulation data which use a realisti ccomputational model for both the dynamics and tribology properties of the oscillatory top and bottom walls that are present in our laboratory.
Soliton dynamics in the ABS nonlinear spinor model with external fields
(IOP Publishing, 2021-09-09) Mertens, Franz G.; Sánchez-Rey, Bernardo; Quintero, Niurka R.; Física Aplicada I; Ministerio de Economía y Competitividad (MINECO). España; Ministerio de Ciencia e Innovación (MICIN). España; FQM392: Física Interdisciplinar y de no Equilibrio; FQM415: Modelado Físico-Matemático de Sistemas no Lineales
We consider the novel nonlinear model in (1 + 1)-dimensions for Dirac spinors recently introduced by Alexeeva, Barashenkov, and Saxena [1] (ABS model), which admits an exact explicit solitary-wave (soliton for short) solution. The charge, the momentum, and the energy of this solution are conserved. We investigate the dynamics of the soliton subjected to several potentials: a ramp, a harmonic, and a periodic potential. We develop a Collective Coordinates Theory by making an ansatz for a moving soliton where the position, rapidity, and momentum, are functions of time. We insert the ansatz into the Lagrangian density of the model, integrate over space and obtain a Lagrangian as a function of the collective coordinates. This Lagrangian differs only in the charge and mass with the Lagrangian of a collective coordinates theory for the Gross-Neveu equation. Thus the soliton dynamics in the ABS spinor model is qualitatively the same as in the Gross-Neveu equation, but quantitatively it differs. These results of the collective coordinates theory are confirmed by simulations, i.e., by numerical solutions for solitons of the ABS spinor model, subjected to the above potentials.
Radionuclides in algae from Swedish coastal waters for over half a century
(Oxford University Press, 2025-09) Mattsson, Sören; Stenström, Kristina Eriksson; Pédehontaa-Hiaa, Guillaume; Bernhardsson, Christian; Jönsson, Mattias; López Gutiérrez, José María; Lérida Toro, Victoria; Chamizo Calvo, Elena; Física Aplicada I; RNM138: Física Nuclear Aplicada
Samples of Fucus serratus and Fucus vesiculosus have been regularly collected at Särdal (56.76 N, 12.63E) on the Swedish west coast since 1967, for most of the time, every two months. In 2020, sampling of Fucus spp. was extended to 44 other locations along the Swedish west, south, and east coast for comparison with Särdal data. At seven of these locations, water samples and extra samples of Fucus spp. were also taken for 3H analysis. Measurements have been performed by gamma spectrometry, or by radiochemical separation followed by low background beta measurements, alpha spectrometry or accelerator mass spectrometry. Time variations of the measured concentrations of various radionuclides (³H, ¹⁴C, ⁶⁰Co, ⁹⁹Tc, ¹²⁹I, ¹³¹I, ¹³⁴Cs, ¹³⁷Cs, ²³⁶U, ²³⁸U, ²³⁹Pu, and ²⁴⁰Pu) are reported. The concentrations have been correlated with emissions from the nuclear fuel reprocessing facilities at Sellafield (UK) and La Hague (France). Contributions from the nuclear power plants in Ringhals and Barsebäck have also been identified, as has fallout from Chernobyl still stored mainly in the sediments and water of the Baltic Sea. In recent decades, studies have shown increasing levels of ¹²⁹I and ²³⁶U and decreases in ¹³⁷Cs, ⁹⁹Tc, and ²³⁹⁺ ²⁴⁰Pu concentrations over time. The ¹⁴4C analyses show an impact of anthropogenic ¹⁴C from activities other than atmospheric nuclear weapons tests in the 1950s and 1960s. The considerable variation in the concentration of different radionuclides over time and along the coasts warrants further studies to determine the possible origin of these radionuclides and to map background data in the event of future releases.
Low-Temperature Remote Plasma Synthesis of Highly Porous TiO2 as Electron Transport Layers in Perovskite Solar Cells
(Wiley, 2025-10-21) Obrero Pérez, José M.; Núñez Gálvez, Fernando; Contreras Bernal, Lidia; Castillo Seoane, Javier; Moreno, Gloria P.; Czermak, Triana; Aparicio Rebollo, Francisco Javier; Rojas, Teresa C.; Ferrer Fernández, Francisco Javier; Borras, Ana; Barranco, Ángel; Sánchez Valencia, Juan Ramón; Química Física; Física Atómica, Molecular y Nuclear; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; European Union (UE)
Halide perovskite solar cells (PSCs) oﬀer high eﬃciency at low productioncosts, making them a promising solution for future photovoltaic technologies.Optimizing charge transport layers is crucial, with porous TiO2 widely used aselectron transport layers (ETLs) due to their suitable energy band alignment,transparency, and abundance. However, their performance dependsstrongly on crystallinity, requiring high-temperature processing (>450 °C),which increases costs and limits their applicability on ﬂexible substrates.Low-temperature wet-chemical methods face scalability issues due tomaterial waste and hazardous solvents. Therefore, plasma-based technologiesprovide a scalable, eco-friendly alternative for fabricating oxide-based ETLs.This study presents a plasma-based synthesis of TiO 2 layers using remoteplasma-assisted vacuum deposition (RPAVD) and soft plasma etching (SPE)at temperatures below 200 °C, enabling precise control over microstructureand porosity. The resulting nanocolumnar and aerogel-like TiO2ﬁlms are antireﬂective and enhance optical and electronic properties, leadingto improved PSC eﬃciency (champion PCE = 14.6%) comparable to high-temperature processed devices. The devices are based on a 3D organometalperovskite with mixed cations (MA, FA, Cs, Rb) and halides (I, Br), witha nominal composition of (Rb 0.03 Cs0.03 FA0.69 MA0.25 )(PbI 3 )0.83 (PbBr 3 )0.17 . Ourresults highlight the potential of RPAVD+SPE for producing low-temperatureETLs, oﬀering a feasible, industrially scalable solution for ﬂexible,high-performance photovoltaics.
Water-resistant hybrid perovskite solar cell - drop triboelectric energy harvester
(Elsevier, 2026) Núñez Gálvez, Fernando; García Casas, Xabier; Contreras-Bernal, Lidia; Descalzo Ruiz, Alejandro; Obrero-Pérez, José Manuel; Castillo Seoane, Javier; Ginés Arteaga, Antonio José; Leger, Gildas; Sánchez López, Juan Carlos; Espinós, Juan P.; Barranco, Ángel; Borrás, Ana; Sánchez Valencia, Juan Ramón; López Santos, Carmen; Física Aplicada I; Química Física; Física de la Materia Condensada; Electrónica y Electromagnetismo; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España
Hybrid energy-harvesting systems that combine perovskite solar cells (PSCs) with drop-driven triboelectric nanogenerators (D-TENGs) offer a compelling solution for continuous power generation under diverse weather conditions. Yet, the inherent vulnerability of halide perovskites to moisture and environmental stressors remains a critical barrier to their widespread deployment. To overcome this bottleneck, we introduce plasma-deposited fluorinated polymers (CFₓ) films as multifunctional encapsulation layers that simultaneously provide water resistance, triboelectric functionality, and optical transparency (>90 %). Plasma deposition enables conformal, room temperature, and solvent-free coating of complex surfaces, ensuring uniform protection without compromising photovoltaic performance. After encapsulation of PSCs with CFx films, power conversion efficiency remained virtually unchanged, and champion cells preserved a PCE of 17.9 %. More importantly, the devices exhibited high environmental stability, retaining over 50 % of their initial PCE for 10 days under high humidity and temperature. Furthermore, CFx layers enabled Spiro-OMeTAD compatibility with commercial UV-curable resins, leading to a thin-film hybrid PSC/D-TENG device capable of simultaneous solar and rain energy harvesting. This device maintained 80 % of its initial performance after 300 h of continuous illumination under humid conditions and demonstrated stability under continuous dripping and illumination for more than 5 h. We demonstrated that optimizing the chemical composition of CFx layers significantly enhances their triboelectric performance. In standalone operation, the optimized CFₓ-based D-TENG, enriched with 36.4 % of (CF2 + CF3) functional species, delivered open-circuit voltage peaks up to 110 V and a maximum power density of ∼4 mW/cm2 under rainwater droplets, while retaining over 85 % of its initial output after more than 17,000 droplet impacts. As a proof of concept, using the same CFx layer for both encapsulation and triboelectric functionality, the hybrid PSC/D-TENG device achieved short-circuit current densities of 11.6 mA/cm2 under 0.5 sun illumination and peak voltages of 12 V per raindrop, enabling simultaneous solar and rain energy harvesting. A self-charging prototype powered LED arrays via a custom boost converter, demonstrating practical multisource energy harvesting for low-power electronics.
Soliton dynamics and stability in the ABS spinor model with a PT-symmetric periodic complex potential
(IOP Publishing, 2024-03-25) Mertens, Franz G.; Sánchez-Rey, Bernardo; Quintero, Niurka R.; Física Aplicada I; Ministerio de Ciencia e Innovación (MICIN). España; Junta de Andalucía; FQM392: Física Interdisciplinar y de no Equilibrio; FQM415: Modelado Físico-Matemático de Sistemas no Lineales
We investigate the effects on solitons dynamics of introducing a PT-symmetric complex potential in a specific family of the cubic Dirac equation in (1+1)-dimensions, called the Alexeeva–Barashenkov–Saxena model. The potential is introduced taking advantage of the fact that the nonlinear Dirac equation admits a Lagrangian formalism. As a consequence, the imaginary part of the potential, associated with gains and losses, behaves as a spatially periodic damping (changing from positive to negative, and back) that acts at the same time on the two spinor components. A collective coordinates (CCs) theory is developed by making an ansatz for a moving soliton where the position, rapidity, momentum, frequency, and phase are all functions of time. We consider the complex potential as a perturbation and verify that numerical solutions of the equation of motions for the CCs are in agreement with simulations of the nonlinear Dirac equation. The main effect of the imaginary part of the potential is to induce oscillations in the charge and energy (they are conserved for real potentials) with the same frequency and phase as the momentum. We find long-lived solitons even with very large charge and energy oscillations. Additionally, we extend to the nonlinear Dirac equation an empirical stability criterion, previously employed successfully in the nonlinear Schrödinger equation.
Functional and semi-transparent CIS solar cells deposited on aesthetic ceramic substrates for building integrated photovoltaic applications
(Elsevier, 2026) Delgado Sánchez, José María; Larrañeta, Miguel; Lillo Bravo, Isidoro; Física Aplicada I; Ingeniería Energética
This work demonstrates the feasibility of directly fabricating functional CuInSe2 (Cis thin film solar cells on commercial ceramic substrates without the use of any diffusion-barrier layer, representing a significant advance compared with previous existing works using ceramic or metallic substrates, which typically require barrier coatings to prevent impurity migration and enhance surface leveling. Two ceramic finishes, matte and polished, were evaluated, exhibing distinct surface morphologies yet comparable compatibility with CIS growth. The ceramic substrates provided natural alkali diffusion to the absorber, enhancing the open-circuit voltage (Voc) and enabling device efficiencies of 5.5 and 5.8 %, close to that of a glass reference cell (6.1 %), thus confirming that ceramic roughness, porosity and ceramic composition do not critically limit performance. Additionally, semi-transparent device architectures were developed by replacing the metallic Mo back contact with a transparent conductive oxide (ITO) layer, achieving >30 % optical transmittance for 100 nm thick absorber layers. Complementary, SCAPS-1D simulations corroborated the experimental trends, indicating that photovoltaic operation remains viable even for ultra-thin absorber layers despite the expected loss in efficiency. These findings validate ceramic substrates as structurally and aesthetically attractive substrate for Building Integrated Photovoltaic (BIPV) applications, establishing a foundation for future optimization toward higher-efficiency CIGS-based devices.
Stability of parametrically driven, damped nonlinear Dirac solitons
(American Institute of Physics, 2025-08-22) Sánchez-Rey, Bernardo; Mellado-Alcedo, David; Quintero, Niurka R.; Física Aplicada I; Matemática Aplicada I; Junta de Andalucía; Ministerio de Ciencia e Innovación (MICIN). España; Universidad de Sevilla; FQM392: Física Interdisciplinar y de no Equilibrio; FQM415: Modelado Físico-Matemático de Sistemas no Lineales
The linear stability of two exact stationary solutions of the parametrically driven, damped nonlinear Dirac equation is investigated. Stability is ascertained through the resolution of the eigenvalue problem, which stems from the linearization of this equation around the exact solutions. On the one hand, it is proven that one of these solutions is always unstable, which confirms previous analysis based on a variational method. On the other hand, it is shown that sufficiently large dissipation guarantees the stability of the second solution. Specifically, we determine the stability curve that separates stable and unstable regions in the parameter space. The dependence of the stability diagram on the driven frequency is also studied, and it is shown that low-frequency solitons are stable across the entire parameter space. These results have been corroborated with extensive simulations of the parametrically driven and damped nonlinear Dirac equation by employing a novel and recently proposed numerical algorithm that minimizes discretization errors. The nonlinear Dirac equation has attracted a lot of attention in recent years. Far from being restricted to the realm of high-energy particle physics, it also describes nonlinear excitations in other fields, such as nonlinear optics and Bose-Einstein condensates. Since these kinds of systems are susceptible to being controlled and manipulated, they constitute an excellent benchmark to study relativistic solitons. Moreover, dissipative losses, present in all physical systems, cause a decay of the soliton amplitude. Therefore, an interesting question is whether a parametric force can inject energy from outside to compensate for the losses in such a way that the soliton becomes stable. In this paper, this question is answered affirmatively. In fact, we prove that one exact stationary soliton solution of the parametrically driven and damped nonlinear Dirac equation is linearly stable in the majority of the parameter space. Furthermore, it is shown that instability regions tend to disappear for sufficiently low frequencies.

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