Artículos (Física de la Materia Condensada)

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Resonant defect states of the SnO2:Ta transparent conductive oxide revealed by excitation wavelength-dependent Raman spectroscopy and hybrid functional DFT calculations
(Royal Society of Chemistry, 2025-04-01) Krause, Matthias; Romero-Muñiz, Carlos; Selyshchev, Oleksandr; Zahn, Dietrich R. T.; Escobar-Galindo, Ramón; Física de la Materia Condensada; Física Aplicada I
Excitation wavelength-dependent Raman spectroscopy, optical spectroscopy, and density functional theory (DFT) calculations with hybrid functionals were used to analyse the electronic structure of defects in SnO2:Ta (1.25 at% Ta) transparent conductive oxide thin films. Based on the Raman excitation profiles of the characteristic D1 and D2 defect modes of two tin vacancy VSn-type defects and one oxygen interstitial Oi-type defect, we derived the corresponding defect-induced electronic transitions of the involved defect states. DFT calculations revealed additional density-of-states for the three point defects at the top of the valence band (VB) in comparison to defect-free SnO2 and SnO2:Ta. The largest distortion of the VB electronic structure was caused by the VSn-type defect with the farthest possible distance from the Ta dopant in the studied 96-atom supercell, and the smallest distortion was caused by the Oi-type defect. Accordingly, the amount of VB splitting showed a reverse order to the electronic transition energies. From the projected defect-density-of-states, we found a delocalized nature of the VSn-type defects and a localized nature of the Oi-type defect, accounting for the different degrees of distortion of the SnO2:Ta electronic structure. Based on these complementary experimental and theoretical results, the electronic structure of point defects in the SnO2:Ta transparent conductive oxide was elucidated in detail. Thus, the proposed approach has great potential to resolve the ongoing controversy about point defects in SnO2.
Influence of outdoor time on the spherical equivalent and axial length in childhood myopia: A meta-analysis
(Wiley, 2025-03-11) Martínez Pérez, Clara; Sánchez Tena, Miguel Ángel; Sánchez González, José María; Villa Collar, Cesar; Álvarez Peregrina, Cristina; Física de la Materia Condensada
This meta-analysis investigates the effectiveness of outdoor activities in reducing the onset of myopia in children and adolescents by analysing changes in axial elongation and spherical equivalent refractive error. Following PRISMA guidelines and registered in PROSPERO (CRD42024592971), the study included randomized controlled trials (RCTs) and observational studies. The eligibility criteria targeted children and adolescents aged 6 to 18 years with varying levels of outdoor exposure. Primary outcomes were axial elongation and spherical equivalent change. Studies were assessed for quality using GRADE and AMSTAR-2 tools, and data were analysed using Review Manager 5.4, with random-effects models applied when heterogeneity was significant. Fifteen studies (9 RCTs and 6 observational) were included, with a total of 16 597 participants. Outdoor activities significantly reduced or delayed the onset of myopia, with a mean axial length difference of −0.08 mm per year (95% CI: −0.09 to −0.07) and a spherical equivalent difference of 0.16 diopters per year (95% CI: 0.07 to 0.25). These differences were observed after 1 year of intervention and sustained for up to 3 years, with daily outdoor exposure ranging from 40 to 120 min. Heterogeneity was moderate to high, but sensitivity analyses confirmed the robustness of the results. While higher outdoor exposure appeared more effective in reducing myopia progression, the certainty of this evidence was rated as low due to suspected publication bias, as indicated by the GRADE analysis. Outdoor activities, especially with prolonged exposure to intense light, effectively reduce or delay the onset of myopia in children and adolescents. This study emphasizes the importance of light intensity in maximizing the benefits of outdoor interventions and highlights regional differences in effectiveness, suggesting that environmental factors play a significant role in the outcomes.
Large low-field-driven electrocaloric effect in organic-inorganic hybrid TMCM-CdCl3
(Nature Research, 2025-04-29) Lin, Yuan; Chai, Congcong; Liu, Zhijie; Wang, Jing; Jin, Shifeng; Yang, Yurong; Law, Jia Yan; Franco García, Victorino; Shen, Baogen; Física de la Materia Condensada; National Key Research and Development Program of China; National Natural Sciences Foundation of China; Chinese Academy of Sciences; European Union (UE); Agencia Estatal de Investigación. España
Due to environmental-friendliness and high-efficiency, electrocaloric effect (ECE) is widely regarded as a refrigeration technology for tomorrow. Herein, utilizing organic-inorganic hybridization strategy, we achieve the largest lowfield-driven ECE and highest directly-measured electrocaloric strength (ECS) via packing sphere-like organic cation (CH3)3NCH2Cl+ (TMCM+ ) into inorganic one-dimension (1-D) CdCl3 chain framework. Single-crystal X-ray (SC-XRD) diffraction combined with Raman Spectra reveals that the simultaneous orderdisorder transition of organic cations and dramatic structure change of inorganic framework are responsible for the large ECE. Moreover, the measured P-E loops and density function theory (DFT) calculations convey that the distinctive electric-field-induced metastable phase and consequential two-step meta-electric transition could lower the transition energy barrier and account for the low driving field. This work shows that the low-symmetry interaction between inorganic framework and organic cations plays a key role in achieving large ECE under low-field, which provides a method for designing highperformance electrocaloric materials via organic-inorganic hybridization.
Incorporating thermal co-evaporation in current-matched all-perovskite triple-junction solar cells
(Royal Society of Chemistry, 2025-01-21) Yang, Terry Chien-Jen; Kang, Taeheon; Fitzsimmons, Melissa; Vega Morrone, Guadalupe; Lu, Yang; Rosado, Leo; Anaya Martín, Miguel; Stranks, Samuel D.; Física de la Materia Condensada; European Union (UE); University of Cambridge; Engineering and Physical Sciences Research Council (EPSRC). U. K.; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España
Thermal co-evaporation of halide perovskites is a solution-free, conformal, scalable, and controllable deposition technique with great potential for commercial applications, particularly in multi-junction solar cells. Monolithic triple-junction perovskite solar cells have garnered significant attention because they can achieve very high efficiencies. Nevertheless, challenges arise in fabricating these devices, as they require multiple layers and precise current matching across complex absorber stacks. Here we demonstrate a current-matched monolithic all-perovskite p–i–n triple-junction solar cell enabled by controlled thermal co-evaporation of various absorber layers in the stack. The top and middle subcells were fabricated by developing optimized thermally co-evaporated Cs0.3FA0.7Pb(I0.56Br0.44)3 (1.80 eV bandgap) and FAPbI3 (1.53 eV) perovskites, respectively, while the bottom subcell employed a solutionprocessed Cs0.25FA0.75Pb0.5Sn0.5I3 (1.25 eV) perovskite. By optimising absorber thicknesses and compositions through optical modelling, we achieve excellent current matching between the top (9.6 mA cm−2 ), middle (9.3 mA cm−2 ), and bottom subcells (9.0 mA cm−2 ), achieving an overall efficiency of 15.8%. Optical modelling simulations suggest that current matching and efficiency up to 11.4 mA cm−2 and 37.6% respectively could be attainable using the latest interlayer materials. This work highlights the potential of scalable vapour-based deposition techniques for advancing multi-junction perovskite-based solar cells, paving the way for future developments in this field
Influence of Dietary Habits on Macular Pigment in Childhood
(MDPI, 2025-04-14) Ponce García, Víctor; Bautista Llamas, María José; García Romera, Marta de la Concepción; Física de la Materia Condensada
Background/Objectives: To analyze the macular pigment optical density (MPOD) values in a child population and to evaluate the relation between MPOD and adherence to the Mediterranean diet using a validated questionnaire specially created for children. Eighty-eight children were included in this cross-sectional study from two primary education schools of Seville (Spain). Methods: MPOD values were measured using Macular Pigment Screener II ®. Lutein and Zeaxanthin intake was evaluated by KIDMED questionnaire, which classifies children according to adherence to the Mediterranean diet. A whole ocular exam with slit-lamp biomicroscopy was conducted by a specialized optometrist. Results: The mean age ranged between 6 and 8 years. The mean MPOD value was 0.46 ± 0.18. The mean score of the KIDMED questionnaire was 7.19 ± 1.85. No statistically significant differences were found as a function of gender or among Mediterranean diet adherence groups. No significant differences in MPOD values between answers were found in any KIDMED questions. No correlations were found for MPOD with several variables, such as Mediterranean diet adherence and KIDMED score. Conclusions: MPOD levels in children could not be correlated with Mediterranean Diet adherence and, thus, good dietary habits. Genetic characteristics, mother’s diet habits, oxidative stress, and body fat composition in children could be the main factors influencing MPOD levels.
Efficacy and Safety of Quantum Molecular Resonance Electrotherapy in Dry Eye Disease: A Systematic Review with Meta-analysis
(Springer, 2025-04-01) Ballesteros Sánchez, Antonio; Rocha de Lossada, Carlos; Sánchez González, José María; Tedesco, Giovanni Roberto; Borroni, Davide; Física de la Materia Condensada; Cirugía
Introduction: This study aimed to investigate the effcacy and safety of quantum molecular resonance (QMR) electrotherapy in patients with dry eye disease (DED). Methods: A systematic review with metaanalysis, reporting the effects of QMR electro therapy in three databases, PubMed, Scopus and Web of Science, was performed according to the PRISMA statement with a search period ending on December 24, 2024. Results: Seven studies, including four open-label, non-comparative trials and three randomized controlled studies (RCTs), were included. Although all studies reported signif cant improvements in most outcome measures after QMR electrotherapy, the meta-analysis indicated that overall effcacy did not signif cantly favor either group when comparing QMR electrotherapy to controls (SMD 0.40; 95% CI − 0.06 to 0.86; P = 0.09; I 2 = 85%). However, only the change in DED symptoms was signif cantly favorable for QMR electrotherapy com pared to controls (SMD 0.69; 95% CI 0.30–1.08; P = 0.0005; I 2 = 28%). In sensitivity analyses, overall effcacy remained non-signifcant when comparing QMR electrotherapy to placebo QMR electrotherapy (SMD 0.14; 95% CI − 0.24 to 0.52; P=0.46; I 2 =65%). Additionally, changes in DED symptoms, TBUT, ST, and CFS also showed no statistically signifcant differences between both groups. Regarding safety, most studies reported no AEs, with a satisfactory tolerability profle for QMR electrotherapy. However, a meta-analysis could not be performed. Conclusions: With the current scientifc litera ture available to date, QMR electrotherapy seems to show some evidence of alleviating DED symp toms. However, evidence supporting its effcacy in improving DED signs and safety remains lim ited. Therefore, further RCTs with robust designs are needed to confrm these fndings.
Microstructural control by freeze-casting of CaO architectures for improved and stable thermochemical energy storage performance
(Elsevier, 2025-07-30) Amghar, Nabil; Ivorra-Martinez, Juan; Perejón Pazo, Antonio; Hanaor, Dorian; Gurlo, Aleksander; Ramírez Rico, Joaquín; Pérez Maqueda, Luis Allan; Sánchez Jiménez, Pedro Enrique; Química Inorgánica; Física de la Materia Condensada; Ministerio de Ciencia e Innovación (MICIN). España
This study investigates the development of porous calcium-based monoliths via freeze-casting (FC) as a novel approach for thermochemical energy storage, particularly within the Calcium Looping (CaL) process. The freeze-casting technique enabled the fabrication of scaffolds with controlled porosity using polyvinyl alcohol (PVA) as a binder. Experimental results demonstrated that freeze-cast monoliths exhibited superior multicycle performance under various carbonation and calcination conditions. The FC-CaCO3 monolith achieved the highest residual conversion of 68.1 % under mild vacuum calcination conditions (780 °C, 0.1 bar CO2), significantly surpassing other configurations. Tests conducted in an inert atmosphere also yielded favorable results, with a conversion of 56.1 %, outperforming equivalent raw powder samples. The enhanced performance is attributed to improved CO2 interaction with the porous structure, mitigating sintering effects and preserving active surface area. Morphological observations by X-ray tomography and SEM confirmed limited particle sintering after multiple cycles, maintaining a reactive surface that supported consistent conversion rates. The pore size distribution of the material evolves upon cycling resulting in an increased microporosity, while the pore network maintains a low tortuosity (τ ~ 1.5–2.0). The addition of dopants such as ZrO2 and SiO2 did not enhance performance, as the monoliths' inherent structure provided sufficient stability. These findings highlight freeze-casting as a promising method for creating advanced porous materials suitable for energy storage applications.
Graphene exfoliation in cyrene for the sustainable production of microsupercapacitors
(Institute of Physics Publishing Ltd., 2025-04-22) Moreira, Pedro; Carvalho, Davide; Abreu, Rodrigo; Alba Carranza, María Dolores; Ramírez Rico, Joaquín; Fortunato, Elvira; Martins, Raúl A.; Pinto, Joana V.; Carlos, Emanuel; Coelho, João; Física de la Materia Condensada; Fundaçao para a Ciencia e a Tecnologia (FCT); Junta de Andalucía; European Union
Graphene and its composites have attracted much attention for applications in energy storage systems. However, the toxic solvents required for the exfoliation process have hampered the exploitation of its properties. In this work, graphene dispersions are obtained via liquid phase exfoliation (LPE) of graphite in cyrene, an environmentally friendly solvent with solubility parameters like those of N-methyl-2-pirrolidone. The obtained dispersions with a concentration of 0.2 mg ml−1 comprised multilayered graphene sheets with lateral sizes in the hundreds of nanometers, as confirmed by scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. Mixing the obtained dispersions with ethanol made it possible to collect the graphene, which was redispersed in 2-Propanol. This active material was used to fabricate supercapacitor electrodes using a scalable spray deposition method on carbon nanotube (CNT) current collectors with the aid of vinyl masks. The device, tested with a PVA/LiCl gel electrolyte, achieved a specific capacitance of 3.4 mF cm−2 (0.015 mA cm−2). In addition, the devices show excellent cycling stability (>10 000 cycles at 0.5 mA cm−2) and good mechanical properties, losing less than 10% of initial capacitance after 1000 bending cycles. This work demonstrates the adaptability of liquid-phase exfoliation to produce graphene sustainably, providing the proof-of-concept for further 2D materials processing and green microsupercapacitor (MSC) fabrication.
Boron nitride nanosheets as an effective strategy against the slow crack growth and hydrothermal ageing in zirconia composites
(Elsevier, 2025-06-18) Muñoz Ferreiro, Carmen; Morales Rodríguez, Ana; Reveron, H.; Guisado Arenas, Elisa; Cottrino, S.; Moreno, P.; Prada Rodrigo, J.; Chevalier, J.; Gallardo López, Ángela María; Poyato, Rosalía; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; European Union (UE)
This paper explores the effectiveness of boron nitride nanosheets in preventing the premature failure of yttria-stabilized tetragonal zirconia ceramics, particularly in humid environments. A simple, low-cost and scalable technique -shear exfoliation in a kitchen blender- was used to prepare BNNS, and pure zirconia and composites with 1, 2.5 and 5 vol. % BNNS were spark plasma sintered. Accelerated hydrothermal ageing experiments in autoclave revealed a remarkable improvement of low temperature degradation resistance in all the composites. Fracture toughness and slow crack growth of the composites with 1 and 2.5 vol. % BNNS were evaluated by bending tests performed in notched specimens. Although the composites presented fracture toughness values similar to those of the reference zirconia, an increase of ∼18 % on crack-tip toughness was achieved. Similar R-curves evaluated in air and in oil-impregnated 2.5 vol. % BNNS composites revealed a limitation of stress-assisted corrosion by water in zirconia, thanks to the BNNS incorporation.
Impact of Tb4+ and morphology on the Thermal Evolution of Tb-doped TiO2 Nanostructured Hollow Spheres and Nanoparticles
(Elsevier, 2021-02-05) Colomer, M. T.; Rodríguez, E.; Morán Pedroso, María; Vattier Lagarrigue, María Florencia; Andrés, A. de; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Universidad de Sevilla. Departamento de Química Inorgánica; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; European Union (UE)
Tb-doped TiO2 hollow spheres (HSs) in the range 0.0-2.0 at.% have been,synthesized by the first time to the best of our knowledge. The HSs are compared with,nanoparticles (NPs) to evaluate the impact of morphology on their physicochemical and,photoluminescence (PL) behavior upon increasing calcination temperature. After,calcination at 550ºC, the particles are anatase with a primary average size of 10.0 ± 0.2,nm for the NPs and 12.0 ± 0.2 nm for those that form the micron sized hollow spheres of,1.8 µm diameter and ca. 64 nm shell thickness. The temperature of the anatase–rutile,transition is found to be strongly dependent on the presence of Tb as well as on,morphology. Contrarily to the usual stabilization of anatase when doping with trivalent,rare-earth ions, the transition temperature is reduced when doping with Tb. The rutile,phase is further favored for the HSs compared to the NPs probably related to the low,density of the HSs and/or a more efficient packing of the nanoparticles that form those,spheres with respect to the packing of the NPs. A slight unit-cell volume decrease for the,anatase structure is observed upon Tb doping, in both the NPs and in the HSs, contrary to,the expected increment due to the larger ionic radius of Tb3+ compared to Ti4+,. In addition,,2,the intensity of the characteristic f-f Tb3+ emission bands is extremely weak both in the,anatase and rutile phases. The transition is accompanied with the emergence of an infrared,emission band centered at 810 nm related to the formation of defects during the structural,transformation providing deep levels in the gap that partly quench the f-f emissions in the,rutile phase. The results are consistent with the presence of Tb in both +3 and +4 valence,states. XPS measurements confirmed the presence of Tb3+ as well as of Tb4+ in both HSs,and NPs with a Tb4+ fraction that increases with increasing Tb doping. The large fraction,of Tb4+ present in the samples originates the weak f-f emission intensity, the slight,decrease of the cell parameters and the destabilization of the anatase phase
Proof of the Nernst theorem
(Springer, 2025-06-13) Martín Olalla, José María; Universidad de Sevilla. Departamento de Física de la Materia Condensada;
The Nernst heat theorem is proven from purely thermodynamic arguments connected with the second law of thermodynamics. The proof stipulates that T 0 is formalized by a Carnot thermometer, and is independent of the vanishing of the specific heats, or the unattainability of the zeroth isotherm. With this proof, the second law of thermodynamics would extend its applicability, and the third postulate of thermodynamics would be narrowed to the fact that the entropy of a finite density, chemically homogeneous body must not be negative.
High Piezoelectric Performance in Lead-free BCHT Fine-grained Ceramics Synthesized by Mechanochemistry
(Elsevier, 2025) Santiago Andrades, L.; Romero Landa, Francisco Javier; Gotor, F. J.; Sayagués, M. J.; Moriche Tirado, Rocío; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Ministerio de Ciencia, Innovación y Universidades (MICIU). España
Lead-free piezoelectric ceramics (Ba1-xCax) (Ti1-yHfy)O3 with stoichiometries close to the morphotropic phase boundary (MPB) were synthesized by high-energy ball milling. The influence of Hf and Ca contents and the sintering method (conventional and hot-press) on the piezoelectric, dielectric, and ferroelectric response was investigated. It was confirmed that the different phases stabilized at room temperature and the structural distortion are strongly dependent on the stoichiometry. The coexistence of tetragonal, orthorhombic and rhombohedral phases was observed in samples with the lowest Ca and Hf contents. These samples, which are in the MPB region, also showed the greatest structural distortion, resulting in higher values of d33. Samples with lower Hf content exhibited a higher coercive field, remnant polarization, and temperature in the ferroelectric to paraelectric transition. Despite the high sintering temperature leading to high densification, grain growth during sintering was limited because of the use of mechanochemically synthesized powders. Although Ba0.85Ca0.15Hf0.10Ti0.90O3 stoichiometry has been reported in the literature as the best for piezoelectric properties, in this work, BCHT solid solution with the lowest dopant content studied (Ba0.90Ca0.10Hf0.05Ti0.95O3) showed the best combination of functional properties. Ceramics of this composition with grain size <2 μm exhibited a d33 > 250 pC/N, with almost no relaxation after 24 h, and the highest permittivity. In the field of piezoelectric materials, there is considerable interest in reducing grain size while maintaining high piezoelectric performance, as this can lead to improvements in mechanical properties.
Piezoelectric and Dielectric Response of BaTiO3/PVDF-TrFE Composites with High β-Phase Content
(American Chemical Society, 2025) Otero Pino, Andrea; Sayagués, M. J.; Romero Landa, Francisco Javier; Gotor, F. J.; Moriche Tirado, Rocío; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Ministerio de Ciencia e Innovación (MICIN). España
The search for flexible piezoelectric materials to build adaptable sensors, electronics, and nanogenerators has becomea key area of interest. The addition of piezoceramic particles to piezoelectric polymers, such as the copolymer poly(vinylidenefluoride-trifluoroethylene) (PVDF-TrFE), is one of the strategies used to enhance the piezoelectric response. In this work, the effectof BaTiO3 content on the β-phase formation, crystallization, and piezoelectric and dielectric properties of the polymer-basedcomposites is investigated. High-energy ball milling was used as an effective, greener technique to achieve well-dispersed mixturescompared to those obtained using organic solvents. During the dispersion process, amorphization and reduction of the crystallinedomain size occur. After compression molding and postprocessing, the crystallinity was recovered and was strongly dependent onthe filler content. Although significant differences in the β-phase fraction were not observed, conformational defects are induced withhigh BaTiO3 contents. The interlayer distances became smaller due to the presence of the ceramic particles after compressionmolding and remained almost unchanged after postprocessing. For the composites, the minimum voltage required to obtain ameasurable piezoelectric coefficient (d33) was significantly reduced compared to neat PVDF-TrFE, even for low contents, which iskey for real applications. Three different piezoelectric behaviors were found depending on the BaTiO3 fraction. For composites with40 vol %, where both matrix and filler contribute to the overall piezoelectric response, the use of a two-step poling method induced asynergistic effect with an increase in d33 of ∼180%. However, the relaxation of the ceramic contribution after 24 h returns the valueof d33 to that obtained by applying a one-step poling strategy.
Pyroelectric Potassium Hydrogen Malate with Polarized Hydrogen Bond Chains and Aligned Dipole Moments
(American Institute of Physics, 2008) de Matos Gomes, E.; Belsley, M. S.; Criado Vega, Alberto; Rodrigues, V. H.; Costa, M. M.R.; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Fundação para a Ciência e a Tecnologia. Portugal
A spontaneous polarization of 16 μC/ cm2 at room temperature has been found in the semiorganic crystal potassium hydrogen malate (KHC 4H4O5 · H2O). This high polarization results from a structural arrangement of oriented dipoles formed by the potassium cations and the COO- group from the malate anion, and long hydrogen bonded polarized chains created by the hydrogen L-malate anion via O-H⋯O interactions, directed along the polar sixfold axis. The material shows a second harmonic generation with a rotationally averaged effective second order susceptibility equal to 0.70 of potassium dihydrogen phosphate at an incident wavelength of 1064 nm.
Space- and Time-resolved Emission Features of Micro- and Nano-sized Perylene-based Zr Metal-Organic Frameworks
(2024-10-15) Romero-Muñiz, Ignacio; García Calvo, José; Romero-Muñiz, Carlos; Rodríguez San Miguel, David; Torres, Tomás; Zamora, Félix; Bottari, Giovanni; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Agencia Estatal de Investigación. España; Ministerio de Ciencia e Innovación (MICIN). España; Comunidad Autónoma de Madrid
While many photoresponsive metal‒organic frameworks (MOFs) have been reported to date, finding applications in several technologically relevant fields such as photocatalysis, sensors, and light-emitting devices, significantly scarcer are the reports addressing the relationship between the MOFs emissive features and their crystalline domain size (i.e., micro- and nano-sized materials). Herein, a valuable contribution is offered to this issue which consists of the use of reticular chemistry to prepare a Zr-MOF featuring spatially separated tetracarboxylated-functionalized perylenes as ligand. Single crystal X-ray analysis of such Zr-MOF revealed the formation of micro- and meso-porous channels. The perylene-based Zr-MOF exhibited notable optoelectronic features, including a relatively small optical bandgap of 1.82 eV and emission features different from that of the constituting perylene ligand in the solid state. Additionally, local probe techniques are used to unveil the emission properties of isolated Zr-MOF crystals. Space- and time-resolved fluorescence studies revealed a strong dependence of the emissive features of the Zr-MOF, both in terms of its intensity and lifetime, to the crystalline domain size.
Fabrication of Al2O3-Y3Al5O12-ZrO2 composites by single-step spark plasma sintering
(Elsevier, 2025-03-12) Vakhshouri, Maryam; Talimian, Ali; Najafzadehkhoee, Aliasghar; Gallardo López, Ángela María; Poyato, Rosalía; Gutiérrez Mora, Felipe; Galusek, Dušan; Universidad de Sevilla. Departamento de Física de la Materia Condensada; European Union (UE)
Fabricating Al2O3-Y3Al5O12-ZrO2 ceramic composites with a eutectic microstructure is challenging and costly, as it requires high-temperature melting of precursor materials. Here, we report on the successful production of Al2O3-Y3Al5O12- 5 mol% ZrO2 composites with lamellar eutectic microstructure through single-step spark plasma sintering (SPS) of sol-gel synthesized powder. The release of volatile species from partially calcined powders, due to limited calcination at 1000°C for 2 h, as well as their fine particle size, were used to create the conditions for local electric discharge and plasma formation during SPS; this resulted in the local formation of eutectic liquids, enabling the formation of lamellar microstructures. The microstructural features can be tailored by modifying the calcination process.
Diversity and composition of ocular microbiota in contact lens wearers: Efficacy of liposomal ozonated oil
(Elsevier, 2025-06) Sánchez González, María del Carmen; Gallardo Real, Inmaculada; Gutiérrez Sánchez, Estanislao; Hita Cantalejo, María Concepción de; Capote Puente, Raúl; Sánchez González, José María; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Universidad de Sevilla. Departamento de Cirugía
Purpose: To characterize the ocular surface microbiota in regular contact lens wearers with dry eyes and assess the effectiveness of reducing bacterial load using a liposomal ozonated oil solution. Methods: This prospective, longitudinal, controlled study randomized subjects into two groups. Group A (45 subjects) received hydroxypropylmethylcellulose (HPMC, Artific®), while Group B (41 subjects) received ozonated sunflower seed oil with soybean phospholipids (OSSO, Ozonest®). Microbial communities were analyzed via DNA metabarcoding of the 16S rRNA gene, and statistical analyses (alpha and beta diversity) were performed in R. Results: Both groups predominantly harbored Staphylococcus caprae, Streptococcus oralis, and Corynebacterium spp., with OSSO and HPMC users showing distinct bacterial profiles. Alpha diversity showed no significant differences, but beta diversity revealed differences in bacterial composition between the groups. Conclusions: The results seem to indicate that the use of ozonized oil reduces the bacterial load compared to the solution used as a control.
Efficacy of eyelid warming devices as first-step treatment in meibomian gland dysfunction: A systematic review with meta-analysis
(Elsevier, 2025-07) Ballesteros Sánchez, Antonio; Rocha de Lossada, Carlos; Sánchez González, José María; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Universidad de Sevilla. Departamento de Cirugía
Purpose: To investigate the efficacy of eyelid warming devices as first-step treatment in patients with meibomian gland dysfunction (MGD). Methods: A systematic review with meta-analysis of RCTs, reporting the effects eyelid warming devices in 3 databases, PubMed, Scopus and Web of Science, was performed according to the PRISMA statement. Results: Seven studies including 367 patients, and 440 eyes were analysed. The overall efficacy did not significantly favor either group when comparing eyelid warming devices to the control groups or warm towel compresses, nor between moisture chamber devices and warm compress devices. However, the change in OSDI questionnaire (SMD 0.91; 95 % CI: 0.44 to 1.39; P = 0.0002) and NIBUT (SMD 1.10; 95 % CI: 0.61 to 1.59; P < 0.0001) were significantly favorable for eyelid warming devices compared to the control groups. Similar results were obtained for tear film stability (SMD 0.97; 95 % CI: 0.32 to 1.61; P = 0.003) when comparing eyelid warming devices to warm towel compresses. Specifically, the sensitivity analysis of these groups revealed that changes in OSDI questionnaire (MD 9.41; 95 % CI: 1.70 to 17.13; P = 0.02; I2 = 49 %) and NIBUT (MD 2.24; 95 % CI: 1.20 to 3.28; P < 0.0001; I2 = 71 %) were significantly favorable for eyelid warming devices. When comparing moisture chamber devices and warm compress devices, only the change in TBUT (SMD 0.75; 95 % CI: 0.23 to 1.28; P = 0.005; I2 = 30 %) were significantly favorable for moisture chamber goggles. Conclusions: Despite their limited overall efficacy, eyelid warming devices significantly reduce OSDI questionnaire and improve NIBUT compared to controls or warm towel compress groups. Evidence remains insufficient to confirm whether moisture chamber devices provide better outcomes than warm compress devices. Further well-designed RCTs are needed to confirm these findings.
Outcomes of Corneal Compound Hyperopic Astigmatism With Presbyopia by Zeiss PRESBYOND Laser Blended Vision LASIK Using Default Custom Refractive Software Master Target Refractions for Reduced Anisometropia
(Slack Incorporated, 2024) Hernández Lucena, Julia; Alonso Aliste, Federico; Amián Cordero, Jonatan; Sánchez González, José María; Universidad de Sevilla. Departamento de Física de la Materia Condensada
PURPOSE: To evaluate the effectiveness, safety, and stability of a modified PRESBYOND Laser Blended Vision protocol (Carl Zeiss Meditec AG) for correcting hyperopic astigmatism and presbyopia, using Custom Refractive Software Master (CRSM) targeting over a 6-month period. METHODS: A total of 636 eyes of 318 patients with a mean age of 51.05 ± 4.71 years (range: 40 to 60 years) met the inclusion and exclusion criteria. All patients completed a 6-month follow-up. CRSM software was used to generate ablation profiles for the MEL90 excimer laser (Carl Zeiss Meditec AG). The target refraction was emmetropic for the dominant eyes and between -0.75 and -1.12 diopters (D) for the near eyes. RESULTS: Visual and refractive results were studied separately by the dominant and non-dominant eyes. The mean attempt to correct for spherical equivalent refraction was +2.17 ± 1.16 D (range: -1.00 to +5.37 D). The mean attempted cylinder was -0.60 ± 0.75 D (range: -4.00 to 0.00 D). All eyes monocularly achieved uncorrected distance visual acuity (UDVA) of 20/25 or better after refractive treatment and 88% achieved 20/20. Binocularly all eyes achieved UDVA of 20/25 or better and 96.54% achieved 20/20. Ninety-eight percent of the patients maintained their corrected distance visual acuity before surgery and UDVA 6 months after surgery. CONCLUSIONS: This hyperopic micro-anisometropia protocol with PRESBYOND Laser Blended Vision was an effective, safe, and well-tolerated refractive treatment. It was an effective procedure with excellent results for UDVA and uncorrected near visual acuity and demonstrates that binocular summation exists.
Phase transition behavior in ferroelectric BaTi0.8Zr0.2O3: Evidence of polar cluster reorientation above Curie temperature
(AIP Publishing, 2025-05-27) Aktas, Oktay; Romero Landa, Francisco Javier; He, Zhengwang; Linyu, Gan; Ding, Xiangdong; Martín Olalla, José María; Gallardo Cruz, María del Carmen; Lookman, Turab; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Natural National Science Foundation of China (NSFC); Scientific and Technological Research Council of Turkey (TÜBİTAK)
We study the phase transition behavior of the ferroelectric BaTi0.8Zr0.2O3 in the paraelectric region above the Curie temperature. The investigation of the phase transition using caloric, dielectric, and elastic measurements indicates that the ferroelectric transition at Tc = 292 K is continuous and displays weakly relaxor characteristics. The nonlinear scaling of entropy and polarization, as well as the temperature dependencies of dielectric and elastic properties, indicates the presence of local structures in the paraelectric phase. The non-zero remnant polarization is measured up to a characteristic temperature T* ∼ 350 K. This temperature coincides with the temperature where the dielectric constant deviates from the Curie–Weiss law and is identified as the coherence temperature T*, associated with the formation of static polar nanostructures. Finally, direct current field cooling in the paraelectric phase using fields smaller than the coercive field leads to an elastic response and remnant piezoelectricity below T*, attributed to the re-orientation of polar nanostructures. The observed remnant effect, along with the temperature dependence of the piezoelectric effect and its time dependence below and above T*, is consistent with increased coherence and slower dynamics of these structures on cooling, leading to symmetry-disallowed remnant piezoelectricity due to glassy behavior below T*.

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