Person: Díaz Blanco, Cristina
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First Name
Cristina
Last Name
Díaz Blanco
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Química Física
Area
Química Física
Identifiers
19 results
Search Results
Now showing 1 - 10 of 19
Item Graphene grown on transition metal substrates: Versatile templates for organic molecules with new properties and structures(Surface Science Reports, 2022) Díaz Blanco, Cristina; Calleja, Fabián; Vázquez de Parga, Amadeo L.; Martín, FernandoThe interest in graphene (a carbon monolayer) adsorbed on metal surfaces goes back to the 60’s, long before isolated graphene was produced in the laboratory. Owing to the carbon-metal interaction and the lattice mismatch between the carbon monolayer and the metal surface, graphene usually adopts a rippled structure, known as moir´e, that confers it interesting electronic properties not present in isolated graphene. These moir´e structures can be used as versatile templates where to adsorb, isolate and assemble organic-molecule structures with some desired geometric and electronic properties. In this review, we first describe the main experimental techniques and the theoretical methods currently available to produce and characterize these complex systems. Then, we review the diversity of moir´e structures that have been reported in the literature and the consequences for the electronic properties of graphene, attending to the magnitude of the lattice mismatch and the type of interaction, chemical or physical, between graphene and the metal surface. Subsequently, we address the problem of the adsorption of single organic molecules and then of several ones, from dimers to complete monolayers, describing both the different arrangements that these molecules can adopt as well as their physical and chemical properties. We pay a special attention to graphene/Ru(0001) due to its exceptional electronic properties, which have been used to induce long-range magnetic order in tetracyanoquinodimethane (TCNQ) monolayers, to catalyze the (reversible) reaction between acetonitrile and TCNQ molecules and to efficiently photogenerate large acenes.- Project number: 350
Item EChemTest: sistema de evaluación de la Calidad en Química(2022) Sánchez Benítez, Francisco Javier; Díaz Blanco, Cristina; Guerrero Martínez, Andrés; Gutiérrez Alonso, Ángel; Lacadena García-Gallo, Francisco Javier; Lainez Ferrando, Alfredo; Pilo Santos, Miguel; Villalba Díaz, MaríaTeresa; García Linares, SaraEste proyecto plantea la herramienta EChemTest como mecanismo de evaluación de la Calidad de un Grado relacionado con la Química. También presenta la oportunidad de evaluar cómo ha influido la docencia online en la adquisición de conocimientos, comparando con cursos anteriores. - Project number: 192
Item Digitalización del laboratorio de Química Física I en tiempos de COVID-19(2021) Guerrero Martínez, Andrés; Díaz Blanco, Cristina; Sánchez Benítez, Francisco Javier; Caselli, Niccolo; Aoiz Moleres, Francisco Javier; Fernández Castillo, Jesús; González MacDowel, Luis; Guzmán Solís, Eduardo; Menéndez Carbajosa, Alicia Marta; Suardíaz del Río, Reynier; Verdasco Costales, Juan Enrique; Marggi Poullain, Sonia Item Optoelectronic properties of electronacceptor molecules adsorbed on graphene/silicon carbide interfaces(Communications materials, 2024) Mansouri, Masoud; Díaz Blanco, Cristina; Martín, Fernando; Springer NatureSilicon carbide has emerged as an optimal semiconducting support for graphene growth. In previous studies, the formation of an interfacial graphene-like buffer layer covalently bonded to silicon carbide has been observed, revealing electronic properties distinct from ideal graphene. Despite extensive experimental efforts dedicated to this interface, theoretical investigations have been confined to its ground state. Here, we use many-body perturbation theory to study the electronic and optical characteristics of this interface and demonstrate its potential for optoelectronics. By adsorbing graphene, we show that the quasiparticle band structure exhibits a reduced bandgap, associated with an optical onset in the visible energy window. Furthermore, we reveal that the absorption of two prototypical electron-accepting molecules on this substrate results in a significant renormalization of the adsorbate gap, giving rise to distinct low-lying optically excited states in the near-infrared region. These states are well-separated from the substrate’s absorption bands, ensuring wavelength selectivity for molecular optoelectronic applications.Item Semiquantum versus quantum methods for grazing-incidence fast-atom diffraction: Influence of the wave-packet size(Physical Review A, 2024) Muzas, Alberto S.; Frisco, Leandro; Bocan, Gisela A.; Díaz Blanco, Cristina; Gravielle, María SilviaTo take full advantage of the capabilities of grazing-incidence fast-atom diffraction (GIFAD) as an experimental technique for analyzing surfaces and phenomena that occur on them, versatile theoretical tools are needed that accurately describe the experiments while allowing a simple but meaningful interpretation at a reasonable computational cost. During the last years, the semiquantum method named surface initial value representation (SIVR) has been postulated to fill this room. However, to date, SIVR has not yet been validated using full quantum calculations as a reference. Here, we have contrasted GIFAD simulations performed with the SIVR approach with those obtained with the full quantum method known as multiconfiguration time-dependent Hartree (MCTDH), taking into account the influence of the size of the initial wave packet. Our comparative study, using GIFAD for the He-LiF(001) system as a benchmark, shows a very good agreement, both qualitative and quantitative, between SIVR and MCTDH simulated diffraction spectra, under different incidence conditions. These findings support the use of SIVR as a versatile theoretical tool to extract as much accurate information as possible from GIFAD experiments.- Project number: PIMCD378/23-24
Item Innovación sobre la docencia y evaluación del laboratorio de Química Física I(2024) Omiste Romero, Juan José; Ahijado Guzmán, Rubén; Blázquez Fernández, Samuel; Caselli, Niccolo; Díaz Blanco, Cristina; Guerrero Martínez, Andrés; Hernández Díaz, María Yolanda; Labrador Páez, Lucía; Marggi Poullaín, Sonia; Pulido Lamas, Cintia; Sánchez Benítez, Francisco Javier; Sola Reija, Ignacio; Suardíaz Delrío, Reynier; Izquierdo Ruiz, Fernando; Lobato Fernández, Álvaro; Sánchez González, Julia Item Engineering the HOMO–LUMO gap of indeno[1,2b]fluorene(Journal of Materials Chemistry C, 2022) Casares, Raquel; Martínez-Pinel, Álvaro; Rodríguez-González, Sandra; Márquez, Irene ; Lezama, Luis; González, Maria Teresa; Leary, Edmund; Blanco, Víctor; Fallaque, Joel ; Díaz Blanco, Cristina; Martín, Fernando; Cuerva, Juan ; Millán, AlbaA direct, efficient and versatile strategy for the modulation of optoelectronic and magnetic properties of indeno[1,2-b]fluorene has been developed. 4-Substituted-2,6-dimethylphenyl acetylene groups placed in the apical carbon of the five-membered rings lead to redshifted absorption maxima (lmax rangin from 600–700 nm) and considerable narrowing of the HOMO–LUMO energy gap (down to 1.5 eV). Experimental and theoretical data show an increase in the diradical character (y) and a decrease of the singlet-triplet energy gap. Moreover, we have investigated the single-molecule conductance of the antiaromatic indeno[1,2-b]fluorene for the first time by including thiomethyl (-SMe) anchor groups on the phenylacetylene moiety. Conductance values one order of magnitude higher than those of a reference linear 3-ring para-phenylene ethylene have been found, despite the longer length of the S-to-S molecular junction. First principles transport calculations support this high conductance value.Item Efficient photogeneration of nonacene on nanostructured graphene(Nanoscale Horizons, 2021) Ayani, Cosme ; Pisarra, Michele; Urgel, José ; Navarro, Juan Jesús; Díaz Blanco, Cristina; Hayashi, Hironobu; Yamada, Hiroko; Calleja, Fabián; Miranda, Rodolfo; Fasel, Román; Martín, Fernando; Vázquez de Parga, AmadeoThe on-surface photogeneration of nonacene from a-bisdiketone precursors deposited on nanostructured epitaxial graphene grown on Ru(0001) has been studied by means of low temperature scanning tunneling microscopy and spectroscopy. The presence of an unoccupied surface state, spatially localized in the regions where the precursors are adsorbed, and energetically accessible in the region of the electromagnetic spectrum where n–p* transitions take place, allows for a 100% conversion of the precursors into nonacenes. With the help of state-of-the-art theoretical calculations, we show that such a high yield is due to the effective population of the surface state by the incoming light and the ensuing electron transfer to the unoccupied states of the precursors through an inelastic scattering mechanism. Our findings are the experimental confirmation that surface states can play a prominent role in the surface photochemistry of complex molecular systems, in accordance with early theoretical predictions made on small molecules.Item Accurate simulations of atomic diffractive scattering from KCl(0 0 1) under fast grazing incidence conditions(Nuclear Instruments and Methods in Physics Research B, 2020) Cueto, Marcos del; Muzas, Alberto; Martín, Fernando; Díaz Blanco, CristinaMotivated by recent experimental and theoretical results, we have studied the diffraction of atoms (D, 3He, 4He) from KCl(001). To perform this study, we have computed continuos potential energy surfaces (PESs) using density functional theory to obtain total interaction energies, with and without taking into account van der Waals forces, and the corrugation reduction procedure. Subsequently, we have performed quantum dynamics simulations using the multi-configuration time-dependent Hartree method. Our simulated spectra compare rather well with those recorded experimentally, specially well for 3He. The agreement is, in general, better for incidence along the [100] direction. In the case of He projectiles, the inclusion of vdW forces does not systematically improve agreement with the experiment. Finally, in agreement with similar calculations for other systems, we have found that the diffraction spectra are quite sensitive to the subtle characteristics of PES, whereas phonons and electronic excitations seem to play a minor role.Item Evaluation of the role of graphene-based Cu(I) catalysts in borylation reactions(Catalysis Science & Technology, 2021) Franco, Mario; Sainz, Raquel; Lamsabhi, Al Mokhtar; Díaz Blanco, Cristina; Tortosa, Mariola; Cid, M. BelénCarbon-supported catalysts have been considered as macromolecular ligands which modulate the activity of the metallic catalytic center. Understanding the properties and the factors that control the interactions between the metal and support allows a fine tuning of the catalyzed processes. Although huge effort has been devoted to comprehending binding energies and charge transfer for single atom noble metals, the interaction of graphenic surfaces with cheap and versatile Cu(I) salts has been scarcely studied. A methodical experimental and theoretical analysis of different carbon-based Cu(I) materials in the context of the development of an efficient, general, scalable, and sustainable borylation reaction of aliphatic and aromatic halides has been performed. We have also examined the effect of microwave (MW) radiation in the preparation of these type of materials using sustainable graphite nanoplatelets (GNP) as a support. A detailed analysis of all the possible species in solution revealed that the catalysis is mainly due to an interesting synergetic Cu2O/graphene performance, which has been corroborated by an extensive theoretical study. We demonstrated through DFT calculations at a high level of theory that graphene enhances the reactivity of the metal in Cu2O against the halide derivative favoring a radical departure from the halogen. Moreover, this material is able to stabilize radical intermediates providing unexpected pathways not observed using homogeneous Cu(I) catalysed reactions. Finally, we proved that other common carbon-based supports like carbon black, graphene oxide and reduced graphene oxide provided poorer results in the borylation process.