@thermogramer: Thermal Imaging as a Tool for Science Communication and E-Learning in Social Media

[Abstract] The COVID-19 pandemic boosted the presence of thermal cameras in our society. These devices are becoming cheaper and smaller and can even be plugged in our smartphones. Therefore, soon enough everybody will have access to these instruments. Thermal cameras have been widely used for industrial, research and/or academic purposes. Now, in the rise of the online era, this work proposes and assesses a new application for such devices as visual engaging tools for science communication and e-learning in social media. Here, we introduce @thermogramer as a science communication channel that shows multispectral (optical and thermal) images of daily life objects to explain the science behind different topics of social interest (climate change, emerging technologies, health, and popular traditions). This young project is already present in social media, press, TV and museum’s exhibitions, and its designed content have been already useful for new inexperienced users, science educators and communicators.This work was funded by Xunta de Galicia and Spanish Ministry of Science (PDC2021-121076-I00

Classic molecular compounds and emergent organic-inorganic hybrid perovskites with (multi) functional properties and (multi)stimuli responsiveness

Programa Oficial de Doutoramento en Química Ambiental e Fundamental. 5031V01[Resumo] Esta Tese de Doutoramento céntrase no desenvolvemento de novos materiais (multi)funcionais e (multi)sensibles, baseados en híbridos orgánico-inorgánicos e compostos moleculares, onde a aplicación de diferentes estímulos externos (temperatura, presión isostática/uniaxial externa e/ou presión química interna) é capaz de inducir unha función específica nestes materiais. Ademais, este estudo trata de atopar novos precursores híbridos de materiais nanoestruturados de carbono. Estas son áreas importantes de investigación en Ciencia de Materiais por mor do potencial destes materiais para aplicacións tecnolóxicas e medioambientais, que están relacionadas coas súas propiedades funcionais como, por exemplo, piezoeletricidade, ferroeletricidade, ferromagnetismo, magnetorresistencia, supercondutividade, multiferroicidade, etc. Neste contexto, esta Tese de Doutoramento explora as propiedades funcionais nos novos compostos híbridos orgánico-inorgánicos de fórmula molecular [TPrA][M(dca)3] (M = Mn2+, Fe2+, Co2+ e Ni2+) e estrutura tipo perovskita; ademais de materiais moleculares coñecidos como o ferroceno, [Fe(C5H5)2], e o amino-borano (H3N·BH3). Estes estudos tamén revelaron efectos calóricos inducidos pola presión sobre o composto [TPrA][Mn(dca)3], o que demostra gran potencial para aplicacións en refrixeración de estado sólido. Finalmente, verificouse que os compostos [TPrA][M(dca)3] (M = Ni2+ e Co2+) son precursores versátiles para sintetizar nanotubos de carbono con nanopartículas magnéticas incorporadas, M@CNTs (M = Ni2+ e Co2+), usando un método sinxelo, escalable e accesible.[Resumen] Esta Tesis Doctoral se centra en el desarrollo de nuevos materiales (multi)funcionales y (multi)sensitivos, basados en híbridos orgánico-inorgánicos y en compuestos moleculares, donde la aplicación de diferentes estímulos externos (temperatura, presión isostática/uniaxial externa y/o presión química interna) es capaz de inducir funcionalidades específicas en estos materiales. Además, este trabajo trata de buscar nuevos precursores híbridos de materiales nanoestructurados de carbono. Estas son importantes áreas de investigación en Ciencia de Materiales, debido al potencial tecnológico y las aplicaciones medioambientales de estos materiales. En este contexto, en esta Tesis Doctoral se han explorado las propiedades funcionales en los nuevos compuestos híbridos orgánico-inorgánicos de fórmula molecular [TPrA][M(dca)3] (M = Mn2+, Fe2+, Co2+ y Ni2+) y estructura tipo perovskita, algunos de los cuales se han sintetizado y/o descrito por primera vez. Además se han estudiado dos materiales moleculares muy conocidos, como son el ferroceno, [Fe(C5H5)2], y el amino-borano (H3N·BH3), en búsqueda de orden ferróico. Asimismo, estos estudios han revelado efectos calóricos inducidos por la presión en el compuesto [TPrA][Mn(dca)3], que muestra un gran potencial para aplicaciones de refrigeración en estado sólido. Finalmente, se ha encontrado que los compuestos [TPrA][M(dca)3] (M = Ni2+ y Co2+) son precursores muy versátiles para obtener nanotubos de carbono con nanopartículas magnéticas embebidas su interior, M@CNTs (Ni2+ y Co2+), mediante un método sencillo, escalable y económicamente accesible.[Abstract] This Ph.D. Thesis focus on the development of new (multi)functional and (multi)stimuli responsive materials, based on organic-inorganic hybrids and molecular compounds, where the application of different stimuli (temperature, external isostatic/uniaxial pressure and/or internal chemical pressure) is able to induce specific functionalities in the materials. Moreover, this work aims to find new hybrid precursors for nanostructured carbon materials. These are important areas of research in Solid State and Materials Science in view of their technological potential and environmental applications. In this context, this Ph.D. Thesis has explored new functional properties on novel organic-inorganic hybrid materials with formula [TPrA][M(dca)3] (M = Mn2+, Fe2+, Co2+ and Ni2+) perovskite-like structure, some of which are synthesized and/or described for the first time. Also two very well-known molecular compounds, namely ferrocene, [Fe(C5H5)2], and ammonia-borane, (H3N·BH3), are investigated in the search for ferroic order. In addition, these studies have revealed pressure-induced caloric effects in the [TPrA][Mn(dca)3], which shows a promising potential for solid state cooling applications. Finally, the [TPrA][M(dca)3] (M = Ni2+ and Co2+) have been found to be very useful precursors in a simple, scalable and economical accessible synthetic method to obtain carbon nanotubes with magnetic nanoparticles embedded, M@CNTs (Ni2+ and Co2+)

Dicyanamide-Perovskites at the Edge of Dense Hybrid Organic–Inorganic Materials

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] Hybrid organic–inorganic ABX3 perovskites with dicyanamide-ligands (dca: [N(CN)2]−) on the X-site are emerging as a distinct group of materials courtesy of their multifunctional properties. Here we present an in-depth analysis of the members of this dicyanamide perovskite family, where the presence of the 5 atom-long dca ligand gives rise to relatively open crystal structures - especially when compared with other dense hybrids such as perovskite formates, and which has a profound influence on their chemistry and properties. We compile the synthetic procedures used to obtain these compounds, along with their chemical and structural properties. In terms of their functional properties, dicyanamide-perovskites have already shown an enormous potential for future applications, such as dielectric or magnetic switches, eco-friendly barocaloric refrigerants at low-pressure and room-temperature, or precursors for oil-recovery nanomaterials and thermoelectric glasses, as reviewed here. Additionally, we highlight several emerging phenomena in this family, and anticipate areas with room for development in the field.This work was financially supported by the Ministerio de Economía y Competitividad (MINECO) and EU-FEDER under the project MAT2017-86453-R, and funding for open access charge was covered by Universidade da Coruña/CISUG J. G.-B. and J. M. B.-G. acknowledges Xunta de Galicia for a Predoctoral and Postdoctoral Fellowships, respectivetly. T.D.B. thanks the Royal Society for a University Research Fellowship (UF150021) and the University of Canterbury Te Whare Wānanga o Waitaha, New Zealand, for a University of Cambridge Visiting Canterbury Fellowship. He would also like to acknowledge, alongside L.N.M, the Leverhulme Trust for a Philip Leverhulme PrizeReino Unido. Royal Society; UF15002

Simple and Low-Cost Footstep Energy-Recover Barocaloric Heating and Cooling Device

[Abstract] In this work, we design, build, and test one of the very first barocaloric devices. The here presented device can recover the energy generated by an individual’s footstep and transform it into barocaloric heating and/or cooling. Accordingly, we present an innovative device that can provide eco-friendly and gas-free heating/cooling. Moreover, we test the device by measuring a new barocaloric organic polymer that exhibits a large adiabatic temperature change of ~2.9 K under the application of 380 bar. These results pave the way towards novel and more advanced barocaloric technologies and provide a simple and low-cost device to explore new barocaloric materials.This research was funded by Ministerio de Economía y Competitividad MINECO and EU-FEDER (project MAT2017-86453-R), and Xunta de Galici

Anomalous and Colossal Thermal Expansion, Photoluminescence, and Dielectric Properties in Lead Halide-Layered Perovskites With Cyclohexylammonium and Cyclopentylammonium Cations

[Abstract] A detailed study of lead halide-layered perovskites with general formula A2PbX4 (where A is cyclohexylammonium (CHA) or cyclopentylammonium (CPA) cation and X is Cl− or Br− anion) is presented. Using variable temperature synchrotron X-ray powder diffraction, we observe that these compounds exhibit diverse crystal structures above room temperature. Very interestingly, we report some unconventional thermomechanical responses such as uniaxial negative thermal expansion and colossal positive thermal expansion in a perpendicular direction. For the polymorphs of (CHA)2PbBr4, the volumetric thermal expansion coefficient is among the highest reported for any extended inorganic crystalline solid, reaching 480 MK−1. The phase transitions are confirmed by calorimetry and dielectric measurements, where the dielectric versus temperature curves show anomalies related with the order-disorder phase transitions. In addition, these compounds exhibit a broad photoluminescence (PL) emission with a large Stokes shift, which is related with an exciton PL emission.This work was financially supported by the Ministerio de Ciencia e Innovación (MICINN) and EU-ERDF under the projects MAT2017-86453-R and PDC2021-121076-I00. We thank Alba synchrotron for the provision of beamtime at BL04-MSPD beamline (experiment 2019023280). We also thank prof. Dr. R. Artiaga and Dr. J.J. López-Beceiro (University of A Coruña) for assistance during DSC measurements. J.M.B.G. thanks Xunta de Galicia for a postdoctoral fellowshi

Narrowing the Tolerance Factor Limits for Hybrid Organic-Inorganic Dicyanamide-Perovskites

[Abstract] In this work we focus in setting the limits of the tolerance factor and the size of the A-cations that stabilize the perovskite structure in hybrid dicyanamide compounds [A][Mn(dca)3]. For this purpose, we propose an alternative, simple approach to calculate a more realistic effective ionic radius for the large and anisotropic A-cations often present in these type of compounds. We test the proposed procedure by analysing the crystal structures of [A][Mn(dca)3] dicyanamide hybrids reported in the literature and recalculating the tolerance factors of such compounds, as well as by preparing five new [A][Mn(dca)3] members, discussing also the influence of the A-cation shape in the stability limits of the perovskite structure. Interestingly, such methodology is not only useful to develop new compounds of the emerging family of (multi)functional multi(stimuli)-responsive dicyanamide materials but can also be applied to other hybrid organic-inorganic perovskites and related materials.As for financial support, the authors thank Ministerio de Economía y Competitividad MINECO and EU-FEDER (projects MAT2017-86453-R and PDC2021-121076-I00), and Xunta de Galicia for the collaboration agreement “Development of research strategic actions Universidade da Coruña I ​+ ​D ​+ ​i 2021–2022: CICA-Disrupting Projects 2021SEM-A3 (NanoCool). J.G.-B. and J.M.B.-G. acknowledge Xunta de Galicia for Predoctoral and Postdoctoral Fellowships, respectively. I.D.-F thanks Ministerio de Universidades for a FPU Predoctoral Fellowship. A. G.-F. and U.B.C thank the Carl Tryggers foundation and the Göran Gustafsson foundation for financial suppor

Multiple phase and dielectric transitions on a novel multi-sensitive [TPrA][M(dca)3] (M: Fe2+, Co2+ and Ni2+) hybrid inorganic–organic perovskite family

The hybrid inorganic–organic [TPrA][M(dca)3] (M: Fe2+, Co2+ and Ni2+) compounds, where TPrA is the tetrapropylammonium cation and dca is the dicyanamide anion, are unique multi-sensitive compounds that display multiple phases and dielectric transitions. These materials exhibit up to three first-order structural transitions (between the polymorphs I, Ia, Ib and II) associated with the same number of dielectric transitions in the temperature range of 210–360 K. The mechanisms responsible for these dielectric responses are found to be novel within the hybrid perovskites, involving ionic displacements of the A-site cations (TPrA) and order/disorder processes of the X anions (dca). In addition, the phase transitions and dielectric transition temperatures can be tuned by applying external hydrostatic pressure or by inducing internal pressure by modifying the tolerance factor through ionic substitution in the B-sites. This multi-sensitive response towards temperature, external and internal pressure opens up promising technological applications for this family of materials, such as dielectric transductors or multistimuli-sensors, whose response can be modulated in a wide range of temperatures and pressuresThe authors are grateful for the financial support from Ministerio de Economía y Competitividad MINECO (MINECO) ENE2014-56237-C4-4-R and Xunta de Galicia under the project GRC2014/042. J. M. B.-G. also wants to thank Barrié Foundation for a predoctoral fellowship and S. Y.-V. to the Xunta de Galicia for a postdoctoral grant (Plan I2C)S

Coexistence of magnetic and electrical order in the new perovskite-like (C3N2H5)[Mn(HCOO)3] formate

This is the accepted manuscript of the following article: Pato-Doldán, B., Gómez-Aguirre, L., Bermúdez-García, J., Sánchez-Andújar, M., Fondado, A., & Mira, J. et al. (2013). Coexistence of magnetic and electrical order in the new perovskite-like (C3N2H5)[Mn(HCOO)3] formate. RSC Advances, 3(44), 22404. doi: 10.1039/c3ra43165gIn this work we further the structural characterization of the recently discovered (C3N2H5)[Mn(HCOO)3] metal–organic framework with perovskite-like structure, and we present its magnetic and dielectric properties up to 350 K. At low temperature, the C3N2H5+ imidazolium cations, that sit oblique within the cavities of the [Mn(HCOO)3]− framework structure, show a cooperative order resulting in an antiparallel arrangement of their electrical dipole moments. Very interestingly, it is only above 220 K that thermal energy seems to be able to break this antiferroelectric order, resulting in a linear increase of its dielectric constant with temperature. In addition, this Mn(II) compound is antiferromagnetic below TN = 9 K, with a slightly non-collinear arrangement of its magnetic moments, yielding to a weak ferromagnetism. Therefore, this is a new multiferroic material which exhibits coexistence of magnetic and electric orderingThe authors are grateful for financial support from Ministerio de Economía y Competitividad MINECO (Spain) under project FEDER MAT2010-21342-C02-01 and from Xunta de Galicia under project PGIDIT10PXB103272PR. B.P.-D. also wants to thank MICINN for a FPI fellowshipS

Discovery of Colossal Breathing-Caloric Effect under Low Applied Pressure in the Hybrid Organic–Inorganic MIL-53(Al) Material

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] In this work, “breathing-caloric” effect is introduced as a new term to define very large thermal changes that arise from the combination of structural changes and gas adsorption processes occurring during breathing transitions. In regard to cooling and heating applications, this innovative caloric effect appears under very low working pressures and in a wide operating temperature range. This phenomenon, whose origin is analyzed in depth, is observed and reported here for the first time in the porous hybrid organic–inorganic MIL-53(Al) material. This MOF compound exhibits colossal thermal changes of ΔS ∼ 311 J K–1 kg–1 and ΔH ∼ 93 kJ kg–1 at room temperature (298 K) and under only 16 bar, pressure which is similar to that of common gas refrigerants at the same operating temperature (for instance, p(CO2) ∼ 64 bar and p(R134a) ∼ 6 bar) and noticeably lower than p > 1000 bar of most solid barocaloric materials. Furthermore, MIL-53(Al) can operate in a very wide temperature range from 333 K down to 254 K, matching the operating requirements of most HVAC systems. Therefore, these findings offer new eco-friendly alternatives to the current refrigeration systems that can be easily adapted to existing technologies and open the door to the innovation of future cooling systems yet to be developed.This work was financially supported by Ministerio de Economía y Competitividad MINECO and EU-FEDER (projects MAT2017-86453-R and PDC2021-121076-I00), Xunta de Galicia and IACOBUS Programme. Funding for open access fee was provided by Universidade da Coruña/CISU

Near-Room-Temperature Reversible Giant Barocaloric Effects in [(CH₃)₄N]Mn[N₃]₃ Hybrid Perovskite

[Abstract] We report giant reversible barocaloric effects in [(CH₃)₄N]Mn[N₃]₃ hybrid organic–inorganic perovskite, near its first-order cubic-monoclinic structural phase transition at ₀ ∼ 305 K. When driving the transition thermally at atmospheric pressure, the transition displays a large change in entropy of ∼80 J K⁻¹ kg⁻¹ and a small thermal hysteresis of ∼7 K, as well as a large change in volume of ∼1.5%. When driving the transition with pressure near room temperature, the transition displays large changes in entropy of ∼70 J K⁻¹ kg⁻¹, which represent a giant barocaloric response. Hybrid perovskites with similar barocaloric response and lower operating temperatures may find applications in environmentally friendly cooling.The authors are grateful for financial support from Ministerio de Economía y Competitividad MINECO and EU-FEDER (MAT2017-86453-R), Xunta de Galicia (ED431G/09), FAMEPA (COOPI-07771/17), and ERC Starting Grant no. 680032Xunta de Galicia; ED431G/0