Artículos (Instituto de Ciencia de Materiales de Sevilla (ICMS) – CIC Cartuja)
URI permanente para esta colecciónhttps://hdl.handle.net/11441/10964
Examinar
Envíos recientes
Artículo Selective H/D Exchange in E–H (E = Si, Ge, Sn) Bonds Catalyzed by 1,2,3-Triazolylidene-Stabilized Nickel Nanoparticles(American Chemical Society, 2025) Molinillo, Pablo; Gálvez Del Postigo, Ana; Puyo, Maxime; Vattier Lagarrigue, María Florencia; Beltrán, Ana M.; Rendón Márquez, Nuria; Lara Muñoz, Patricia; Suárez, Andrés; Universidad de Sevilla. Departamento de Química Inorgánica; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Ministerio de Ciencia e Innovación (MICIN). España; European Union (UE)Nickel nanoparticles (Ni·MIC) stabilized with mesoionic 1,2,3-triazolylidene (MIC) ligands were prepared via decomposition of the [Ni(COD)2] (COD = 1,5-cyclooctadiene) complex with H2 (3 bar) in the presence of 0.2 or 0.5 equiv of ligand. The obtained monodisperse and small-sized (3.2–3.8 nm) nanoparticles were characterized by high-resolution transmission electron microscopy (TEM, HRTEM) and inductively coupled plasma (ICP) analysis. Further analysis of the nickel nanoparticles by X-ray photoelectron spectroscopy (XPS) demonstrated the coordination of the MIC ligands to the metal surface. Finally, the Ni·MIC nanoparticles were applied in the isotopic H/D exchange in hydrides of group 14 elements (Si, Ge, Sn) using D2 gas under relatively mild conditions (1.0–1.8 mol % Ni, 1 bar D2, 55 °C). High and chemoselective deuterium incorporation at the E–H (E = Si, Ge, Sn) bond in these derivatives was observed.
Artículo Quantification of the H Content in Diamondlike Carbon and Polymeric Thin Films by Reflection Electron Energy Loss Spectroscopy(American Institute of Physics, 2005) Yubero, F.; Rico, V. J.; Espinós, J. P.; Cotrino Bautista, José; González-Elipe, A. R.; Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear; Ministerio de Educación y Ciencia (MEC). EspañaA nondestructive method to determine the hydrogen content at the surface of diamondlike carbon and polymeric thin films is proposed. The method relies on the analysis of the elastic peak produced by backscattering of electrons from the hydrogen atoms present at the sample surface. Quantitative analysis of the H content at the surface is achieved through use of a phenomenological sensitivity factor for elastic electron backscattering by H atoms with respect to other atoms present at the surface of reference polymeric samples. The validity of the method is checked with elastic recoil detection measurements and infrared spectroscopy analysis of the same samples. The accuracy of the method in the determination of H content at the sample surface is estimated to be ±10%.Artículo 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. PortugalA 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.Artículo Formation of the complete range of Ti5Si3-xGe x solid solutions via mechanically induced self-sustained reactions(Elsevier, 2011-11) Córdoba Gallego, José Manuel; Chicardi Augusto, Ernesto; Avilés Escaño, Miguel Ángel; Gotor Martínez, Francisco José; Universidad de Sevilla. Departamento de Química Inorgánica; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Agencia Estatal de Investigación. EspañaThe complete range of Ti5Si3-Ti5Ge 3 solid solutions was synthesised from elemental mixtures of Ti, Si, and Ge under an inert atmosphere via mechanically induced self-sustaining reactions (MSR). The stoichiometry of Ti5Si3-xGe x solid solutions was controlled by adjusting the Si/Ge ratio of the initial mixture. The chemical composition and lattice parameters of the materials confirmed that Ti5Si3-Ti5Ge 3 solid solutions with good chemical homogeneity could be produced via MSR.Artículo V2O5/TiO2 Catalyst for Catalytic Glucose Oxidation to Formic Acid in Batch Reactor: Vanadium Species Nature and Reaction Conditions Optimization(Springer, 2024-07-04) Álvarez Hernández, Débora; Ivanova, Svetlana; Domínguez Leal, María Isabel; Martínez Blanes, José María; Centeno Gallego, Miguel Ángel; Universidad de Sevilla. Departamento de Química Inorgánica; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España; European Union (UE)This study focused on the development of vanadium-based catalysts for formic acid production from glucose. The influence of different vanadium precursors on the catalytic activity of titania supported catalysts was contemplated and compared to the performance of commercial and synthesized unsupported V2O5. The obtained results reveal a successful deposition of multiple vanadium species on TiO2 as confirmed by XRD, Raman, and UV-Vis measurements. Catalyst screening identifies V5+ species as main player indicating its important oxidizing potential. Afterwards, the key reaction conditions, as temperature, time, pressure and catalyst loading, were optimized as well as the state of the catalyst after the reaction characterized.Artículo 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.Artículo Solid-state spectroscopic, thermokinetics and thermal analysis of aceclofenac coordination complexes with lanthanum and gadolinium(Soc Brasileira Quimica, 2024-05-24) Melo, Laís D. S. M. K; Carvalho, Cláudio T.; Sánchez Jiménez, Pedro Enrique ; Sequinel, Thiago; Perejón Pazo, Antonio; Pérez Maqueda, Luis Allan ; Colman, Tiago A. D.; Universidad de Sevilla. Departamento de Química Inorgánica; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). Brasil; Finaciadora de Estudos e Projetos (FINEP). BrasilIn recent years, the field of coordination chemistry has experienced a surge in interest regarding the synthesis and characterization of coordination complexes for diverse applications. This study is dedicated to investigating coordination compounds resulting from the interaction of nonsteroidal anti-inflammatory drugs (NSAIDs) with metal ions. The study research places significant emphasis on understanding the stability and thermal behavior of these coordination compounds. The utilization of thermoanalytical techniques is crucial in achieving this goal. Thermal analysis and thermokinetics provide valuable insights into the underlying mechanisms, kinetics, and energetics of these reactions, thereby facilitating the optimization of synthesis procedures. The research employs concurrent techniques, namely thermogravimetric analysis (TG) and differential scanning calorimetry (DSC), to explore the thermal stability and decomposition pathways of these coordination compounds. Thermokinetic models and optimization methodologies are subsequently applied to identify key reaction parameters. The primary aim of this research is to unveil the thermal behavior, stability, and reaction kinetics of aceclofenac coordination compounds, thus contributing significantly to the understanding of thermokinetics and thermal analysis in the domain of coordination chemistry. Specifically, this study is focused on aceclofenac coordination complexes involving lanthanum and gadolinium, with the ultimate goal of advancing the field of coordination chemistryArtículo Integrated CO2 capture and dynamic catalysis for CO2 recycling in a microbrewery(Elsevier, 2025-02) Merkouri, Loukia Pantzechroula; Bobadilla Baladrón, Luis Francisco; Martín Espejo, Juan Luis; Odriozola Gordón, José Antonio; Penkova, Anna Dimitrova; Torres Sempere, Guillermo; Ramírez Reina, Tomás; Short, Michael; Duyar, Melis S.; Universidad de Sevilla. Departamento de Química Inorgánica; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España; European Union (UE)In this study, we used fermentation off-gases from a brewery for integrated CO2 capture and utilisation in order to produce CH4 with a dual-function material (DFM) containing NiRu as catalyst and dispersed CaO as adsorbent. CH4 was produced from captured CO2 via 2 pathways (fast and slow), proceeding through formyl intermediates according to the operando DRIFTS-MS results. The NiRuCa DFM showed a stable CH4 capacity over 8 cycles (105 μmol/gDFM) with fermentation off-gases being used as a CO2 capture feed. H2O and O2, which were present in small amounts in the emissions feed, resulted in the passivation of Ni in the form of a NiO layer and hence, the DFM did not undergo excessive oxidation and deactivation. This work constitutes a first in terms of validating the use of DFMs with real industrial emissions, and it directly correlates the DFM activity performance with its reaction mechanism and intermediate species.Artículo Improving the photocatalytic degradation of EDTMP: Effect of doped NPs (Na, Y, and K) into the lattice of modified Au/TiO2 nano-catalysts(Elsevier, 2025-01) Riedel, Ramona; Schowarte, Julia; Semisch, Laura; González Castaño, Míriam; Ivanova, Svetlana; Arellano-García, Harvey; Martienssen, Marion; Universidad de Sevilla. Departamento de Química InorgánicaThis study presents the photocatalytic degradation of the aminophosphonate ethylenediaminetetra(methylenephosphonic acid) (EDTMP) with a range of different doped nanoparticles (NP). The photocatalysts were based on TiO2 benchmark P25 and gold (Au) doped either with sodium (Na), potassium (K) or yttrium (Y). The synthesized photocatalysts were characterized via TEM, XRF, XRD, UV-DRS (band gap estimation) and N2-physisorption. Photocatalytic pre-screening at pH values of 3, 7 and 10 indicated highest o-PO4 release of EDTMP at pH 7 and 10 for NP either doped with K or Y. The results of LC/MS analysis showed that the NPs doped with 5 % Y (Au2/Y5/P25) resulted in the fastest degradation of EDTMP. The target compound was completely degraded within 60 min, 4 times faster than photochemical treatment of unadulterated EDTMP. Importantly, also the transformation products were accelerated by the photocatalytic treatment with Au2/P25 either doped with 5 % Y or 10 % K. The results of scavenger experiments indicated that the enhanced photocatalytic degradation of EDTMP is primarily attributable to the presence of hydroxyl radicals in the bulk and to a lesser extent to •O2 − and electron-holes (h+) at the surface of the catalysts. The study demonstrates that the catalytic efficiency of TiO2 nanocomposites is significantly influenced by the choice of dopants, which affect particle size, band gap, and photocatalytic activity. Yttrium at low concentrations (i.e., 5 wt% Y) doping emerged as particularly effective, enhancing both the visible light absorption and h+ separation, leading to superior photocatalytic performance in the degradation of EDTMP. The Au content also plays a crucial role in enhancing the photocatalytic efficiency. However, the combination of Au and Na doping was found to be less effective for this photocatalysis in aqueous media, potentially due to larger particle sizes and insufficient dopant contents. In conclusion, the findings emphasise the necessity of optimising both the selection of dopants and the design of catalysts in order to enhance photocatalytic applications.Artículo Improved CO selectivity during CO2 hydrogenation by bimetallic copper-cobalt supported SBA-15(Elsevier, 2025-02) Escamilla, María; Caballero Martínez, Alfonso; Colón, Gerardo; Universidad de Sevilla. Departamento de Química Inorgánica; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España; European Union (UE)Co-Cu/SBA-15 systems have been studied for the reverse water gas shift (rWGS) reaction within mild temperature range of 250–650 ºC. CuOx and CoOx species at different weight ratios were deposited from wet impregnation method over SBA-15 support. We have stated that pre-reduction treatment before reaction leads to the complete Co and Cu reduction for Co-Cu/SBA systems. A low copper content on Co/SBA system leads to similar CO2 conversion than monometallic Co-catalyst. However, competitive Sabatier side reaction appears almost suppressed. So, upon Cu incorporation a significant improvement on CO yield has been attained with respect to Co/SBA catalyst. Thus, a good compromise is attained at 450 ºC using Co5Cu5/SBA catalyst for which a stable CO2 conversion of 22 % and 97 % CO selectivity has been obtained under lowest H2:CO2 ratio.Artículo Direct biogas methanation at moderate pressure: Mechanism investigation over Ni-based catalysts(Elsevier, 2025-03) Giarnieri, Ilenia; Chen, Sining; Ballesteros Plata, Daniel; Holgado, Juan P.; Maluta, Francesco; Caballero Martínez, Alfonso; Mata Benito, Patricia; Universidad de Sevilla. Departamento de Química Inorgánica; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; European Union (UE); Junta de AndalucíaDirect upgrading of biogas by CO2 methanation aims to produce a gas to be injected into the grid. Operating at moderate pressures favors thermodynamics, but catalyst surface and reaction mechanism under realistic conditions are not well investigated. We study the role of basic and metallic sites on performance and mechanism of clean biogas methanation (CO2/CH4=1/1 v/v) at 1, 5 and 7 bar. Ni/Mg/La/Al hydrotalcite-derived catalysts, with different Ni and La contents, are investigated combining tests and physico-chemical characterization, including quasi-in situ XPS at 7 bar, with CO2-adsorption and methanation DRIFTS at 1 and 7 bar, respectively. An optimized catalyst (6.5 wt% La, 35 wt% Ni) with 3–4 nm Ni0 and balanced basicity, achieves 96 LCH4*gcat− 1 * h− 1 (300◦C, 7 bar). DRIFTS confirm catalysts activity experimental trend. Optimizing Ni and La results in higher consumption rates of formate intermediate and sufficient Ni0 sites for CO formation. Increasing pressure to 7 bar promotes CO and m-HCOO reactivity.Artículo Effect of Temperature Variations on Equilibrium Distances in Levitating Parallel Dielectric Plates Interacting through Casimir Forces(American Institute of Physics (AIP), 2016) Esteso Carrizo, Victoria; Carretero Palacios, Sol; Míguez, Hernán; Universidad de Sevilla. Departamento de Física de la Materia Condensada; European Union (UE); Ministerio de Economía y Competitividad (MINECO). EspañaWe study at thermal equilibrium the effect of temperature deviations around room temperature on the equilibrium distance (deq) at which thin films made of Teflon, silica, or polystyrene immersed in glycerol levitate over a silicon substrate due to the balance of Casimir, gravity, and buoyancy forces. We find that the equilibrium nature (stable or unstable) of deq is preserved under temperature changes, and provide simple rules to predict whether the new equilibrium position will occur closer to or further from the substrate at the new temperature. These rules depend on the static permittivities of all materials comprised in the system (ϵ0(m)) and the equilibrium nature of deq. Our designed dielectric configuration is excellent for experimental observation of thermal effects on the Casimir force indirectly detected through the tunable equilibrium distances (with slab thickness and material properties) in levitation mode.Artículo Textile microfibers valorization by catalytic hydrothermal carbonization toward high-tech carbonaceous materials(American Association for the Advancement of Science, 2024-11-18) Parrilla Lahoz, Silvia; Zambrano, Marielis C.; Pawlak, Joel J.; Venditti, Richard A.; Ramírez Reina, Tomás; Odriozola Gordón, José Antonio; Duyar, Melis S.; Universidad de Sevilla. Departamento de Química Inorgánica; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; Next Generation EuropeMicroplastics fibers shed from washing synthetic textiles are released directly into the waters and make up 35% of primary microplastics discharged to the aquatic environment. While filtration devices and regulations are in development, safe disposal methods remain absent. Herein, we investigate catalytic hydrothermal carbonization (HTC) as a means of integrating this waste (0.28 million tons of microfibers per year) into the circular economy by catalytic upcycling to carbon nanomaterials. Herein, we show that cotton and polyester can be converted to filamentous solid carbon nanostructures using a Fe-Ni catalyst during HTC. Results revealed the conversion of microfibers into amorphous and graphitic carbon structures, including carbon nanotubes from a cotton/polyethylene terephthalate (PET) mixture. HTC at 200°C and 22 bar pressure produced graphitic carbon in all samples, demonstrating that mixed microfiber wastes can be valorized to provide potentially valuable carbon structures by modifying reaction parameters and catalyst formulation.Artículo The impact of interfacial quality and nanoscale performance disorder on the stability of alloyed perovskite solar cells(Nature Research, 2024-10-30) Frohna, Kyle; Chosy, Cullen; Al-Ashouri, Amral; Scheler, Florian; Chiang, Yu-Hsien; Dubajic, Milos; Anaya Martín, Miguel; Stranks, Samuel D.; Universidad de Sevilla. Departamento de Física de la Materia Condensada; European Union (UE). H2020; Engineering Physical Sciences Research Council (EPSCR) U. K.Microscopy provides a proxy for assessing the operation of perovskite solar cells, yet most works in the literature have focused on bare perovskite thin flms, missing charge transport and recombination losses present in full devices. Here we demonstrate a multimodal operando microscopy toolkit to measure and spatially correlate nanoscale charge transport losses, recombination losses and chemical composition. By applying this toolkit to the same scan areas of state-of-the-art, alloyed perovskite cells before and after extended operation, we show that devices with the highest macroscopic performance have the lowest initial performance spatial heterogeneity—a crucial link that is missed in conventional microscopy. We show that engineering stable interfaces is critical to achieving robust devices. Once the interfaces are stabilized, we show that compositional engineering to homogenize charge extraction and to minimize variations in local power conversion efciency is critical to improve performance and stability. We fnd that in our device space, perovskites can tolerate spatial disorder in chemistry, but not charge extraction.Artículo Revisiting Stability Criteria in Ball-Milled High-Entropy Alloys: Do Hume–Rothery and Thermodynamic Rules Equally Apply?(Willey, 2024-10-07) Blázquez Gámez, Javier Sebastián; Manchón Gordón, Alejandro F.; Vidal Crespo, Antonio; Caballero Flores, Rafael; Ipus Bados, Jhon Jairo; Conde Amiano, Clara Francisca; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Junta de Andalucía; Universidad de SevillaStability descriptors for the formation of solid solutions can be divided into two categories: inspired by Hume–Rothery rules (HRR) and derived from thermodynamic approaches. Herein, HRRs are extended from binary to high-entropy alloys (HEAs) focusing on compositions prepared by ball milling. Parameters describing stability criteria are interrelated and implicitly account for the microstrains’ storage energy, more determinant than entropy increase in stabilization of HEAs and more effective in bcc structures than close-packed ones (fcc and hcp). An effective temperature, Teff, is defined as the ratio between increase in metallic bonding energy of solid solutions with respect to segregated pure constituents and configurational entropy. This versatile parameter is used as a threshold for stabilization of HEAs at equilibrium and out of equilibrium. When Teff is below room temperature, HEA would be stable at equilibrium. When Teff is below melting temperature, HEA would be obtained by rapid quenching. Limitations related to electronegativity differences remain valid in mechanically alloyed solid solutions. However, ball milling broadens the allowed differences in atomic size to form HEA. Moreover, thermodynamic criteria can be surpassed in these systems, allowing the formation of single-phase solid solutions beyond the compositional range predicted by those criteria.Artículo Navigating the Legislative Interventions, Challenges, andOpportunities in Revolutionizing Textile Upcycling/RecyclingProcesses for a Circular Economy(American Chemical Society (ACS), 2024) Saif, Maria; Blay Roger, José Rubén; Zeeshan, Muhammad; Bobadilla Baladrón, Luis Francisco; Ramírez Reina, Tomás; Nawaz, Muhammad Asif; Odriozola Gordón, José Antonio; Universidad de Sevilla. Departamento de Química Inorgánica; Ministerio de Ciencia e Innovación (MICIN). España; European Union (UE)Embracing a circular economy in the textile industry represents a crucial steptoward sustainability, where fashion and textile sectors contribute significantly to CO2emissions. However, transitioning from a linear “take-make-waste” model to circularity,poses multifaceted challenges, that highlight the staggering volume of annual textile wastesurpassing industry predictions, thus emphasizing the urgent need for comprehensivestrategies. Despite advancements in recycling technologies, challenges persist in collectingand sorting textile waste, where fragmentation in waste management and recycling processeshinders effective management of post-consumer waste. Addressing these challenges demandselevated efforts in collection, sorting, and pre-processing, alongside regulatory interventions todrive enhanced waste collection and circular business models. Efforts are underway to promotesustainable textile recycling, with initiatives like the EU’s Sustainable and Circular TextilesStrategy aiming to reduce reliance on virgin resources. However, achieving a circular textilemarket in the near future requires collaborative action and innovative solutions. Thoughchallenges in scaling and technological limitations still remain, recent breakthroughs in textile-recycling technologies offer promise,signaling a shift toward scalable and sustainable alternatives to virgin fibers, where bio-based chemical processes, andthermochemical recycling processes present transformative opportunities. Where, bold scaling targets, collaborative efforts, andshort-term funding support narrated in this perspective article are imperative to accelerate the transition to a circular textileeconomy, thus delving into the pivotal role of textile recycling, tracing the evolution of recycling technologies, and addressing criticalchallenges hindering widespread adoption.Artículo Magnetostructural transformation and magnetocaloric response in Mn(Fe)NiSi(Al) alloys(Elsevier, 2024-09-30) Khan, Aun N.; Moreno Ramírez, Luis Miguel; Law, Jia Yan; Franco García, Victorino; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; Oficina de Investigación Científica de la Fuerza Aérea. EE. UU.; European Innovation Council. E. U,An efficient magnetocaloric refrigerant must have certain characteristics such as a sharp transition near the desired working temperature, a large cyclic magnetocaloric response, and the use of raw materials with reduced costs and low environmental consequences. In this sense, this work focuses on a series of rare-earth- and Co-free Mn0.5Fe0.5NiSi1-xAlx alloys (x = 0.0525, 0.060, 0.0685) with promising magnetocaloric properties. The alloys were synthesized using combined arc melting and induction melting techniques, as this synthesis route provides improved control on the sample composition and homogeneity. We investigated how the heat treatment temperature and Al content affect the magnetostructural and magnetocaloric properties of the alloys. On the one hand, it is found that annealing at 1173 K for 7 days leads to a sharp magnetostructural transformation with no traces of impurities for the alloy with x = 0.0525. Under these conditions, a large isothermal entropy change of –11.5 J kg−1 K−1 for 1 T is obtained near room temperature, significantly improving the value of the as-cast sample. On the other hand, following this optimal heat treatment, the influence of Al content is studied: upon increasing the Al concentration the magnetostructural transformation shifts to lower temperatures, ranging from 320 K for x = 0.0525 to 220 K for x = 0.0685 (measured upon heating).Artículo Interplay between connectivity and passivating agents in perovskite quantum dot networks(Royal Society of Chemistry, 2024-10-02) Morán Pedroso, María; Tiede, David O.; Romero-Pérez, Carlos; Calvo, Mauricio E.; Galisteo López, Juan F.; Míguez, Hernán; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; Unión Europea NextGeneration; Junta de AndalucíaIntroducing quantum dots (QDs) as the active element of an optoelectronic device demands its incorporation in the shape of interconnected arrays that allow for some degree of electronic coupling in order to inject/extract charge carriers. In doing so, beyond reducing the degree of quantum confinement, carriers are exposed to an enhanced defect landscape as they can access adjacent QDs, which is at the origin of the strong reduction of photoluminescence observed in QD solids when compared to that of the isolated QDs. In this work we demonstrate how a proper defect passivating strategy or atmospheric treatment can greatly enhance charge diffusion in a QD film, needed for an optimal carrier injection/extraction demanded for optoelectronic applications, and also improved its stability against external radiation. From a fundamental perspective, we provide evidence showing that trap density distribution, rather than QD size distribution, is mostly responsible for the observed variations in emission decay rates present in the QD networks under analysis.Artículo Influence of the chemical activation with KOH/KNO3 on the CO2 adsorption capacity of activated carbons from pyrolysis of cellulose(Elsevier, 2024-10-07) Lamata Bermejo, Irene; Alba, María D.; Ramírez Rico, Joaquín; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Junta de Andalucía; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER)Plant biomass is an attractive precursor to prepare activated carbons with high surface area for CO2 adsorption due to its low-cost and easy regeneration. Despite this interest, there are still remaining questions regarding the optimal processing conditions and the choice of activating agent. Moreover, since plant biomass shows a highly variable proportion of different biopolymers (cellulose, hemicellulose, lignin), it is important to understand the activation effect on each constituent. In this work, carbons obtained from pyrolysis of cellulose were activated using two potassium salts, using two different activation temperatures. The samples were characterized to elucidate the influence of the activation conditions on their CO2 adsorption capacity. In general, all the carbons activated at higher temperature showed higher adsorption capacity. These results are comparable with other carbons derived from biomass described in the bibliography. Among the activated carbons studied, the carbon activated only with KOH exhibits the highest CO2 adsorption capacity at 1 bar meanwhile the highest adsorption capacity at saturation pressure belongs to the carbon activated with larger ratio of KNO3.Artículo Compositional Gradient of Mixed Halide 2D Perovskite Interface Boosts Outdoor Stability of Highly Efficient Perovskite Solar Cells(Willey, 2023-12-23) Degani, Matteo; Pallotta, Riccardo; Pica, Giovanni; Karimipour, Masoud; Mirabelli, Alessandro; Frohna, Kyle; Anaya Martín, Miguel; Grancini, Giulia; Universidad de Sevilla. Departamento de Física de la Materia Condensada; European Research Council (ERC); European Union (UE). H2020; Engineering and Physical Sciences Research Council (UK)Interface engineering using self-assembled 2D perovskite interfaces is a consolidated route to efficient and durable perovskite solar cells. Whether the 2D perovskite forms a homogeneous conformal layer or is heterogeneously distributed on the surface, interface defects are passivated, leading to a general improvement in the device's open circuit voltage (VOC) and stability. Here, an innovative strategy is developed for manipulating the composition of the 2D/3D perovskite interface that results in the formation of a gradient halide distribution, which extends from the surface to the bulk. The use of a bromide-based 2D perovskite triggers a progressive Br/I exchange, affecting not only the surface but also the perovskite underneath. As a result, not only the device VOC improve, as expected, but also the photogenerated current is boosted, leading to a device efficiency of up to 24.4%. Such mixed halide gradient effectively passivates surface and bulk defects making the perovskite active layer more efficient and robust, as demonstrated by the superior device stability showing zero losses in performances upon 36 days (more than 800 h) test in outdoor conditions, those ones relevant for a marketable product.