Raman Spectroscopy and DFT calculations for the Electronic Structure Characterization of Conjugated Polymers

Flash presentationIn the last three decades, there has been a broad academic and industrial interest in conjugated polymers as semiconducting materials for organic electronics. Their applications in polymer light-emitting diodes (PLEDs), polymer solar cells (PSCs), and organic field-effect transistors (OFETs) offer opportunities for the resolution of energy issues as well as the development of display and information technologies1. Conjugated polymers provide several advantages including low cost, light weight, good flexibility, as well as solubility which make them readily processed and easily printed, removing the conventional photolithography for patterning2. A large library of polymer semiconductors have been synthesized and investigated with different building blocks, such as acenes or thiophene and derivatives, which have been employed to design new materials according to individual demands for specific applications. To design ideal conjugated polymers for specific applications, some general principles should be taken into account, including (i) side chains (ii) molecular weights, (iii) band gap and HOMO and LUMO energy levels, and (iv) suited morphology.3-6 The aim of this study is to elucidate the impact that substitution exerts on the molecular and electronic structure of π-conjugated polymers with outstanding performances in organic electronic devices. Different configurations of the π-conjugated backbones are analyzed: (i) donor-acceptor configuration, (ii) 1D lineal or 2D branched conjugated backbones, and (iii) encapsulated polymers (see Figure 1). Our combined vibrational spectroscopy and DFT study shows that small changes in the substitution pattern and in the molecular configuration have a strong impact on the electronic characteristics of these polymers. We hope this study can advance useful structure-property relationships of conjugated polymers and guide the design of new materials for organic electronic applications.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Analysis of the Impact of the European Funds in Andalusia in 2007-2013 through a General Equilibrium Model

Ever since the accession of Spain to the European Economic Community, Andalusia has been recipient of European Funds. This paper proposes an analysis that will reveal the economic impact of the European Funds received by the Autonomous Region of Andalusia during the period 2007-2013. With this purpose, a Computable General Equilibrium (CGE) model will be implemented to assess, in different simulation scenarios, the effects of those funds on the main macroeconomic indicators. The results will highlight the significant contribution of the European Funds to the regional growth during the period analysed

Conjugated Polymers for Organic Electronics: Structural and Electronic Characteristics

The use of organic materials to design electronic devices has actually presented a broad interest for because they constitute an ecological and suitable resource for our current "electronic world". These materials provide several advantages (low cost, light weight, good flexibility and solubility to be easily printed) that cannot be afforded with silicium. They can also potentially interact with biological systems, something impossible with inorganic devices. Between these materials we can include small molecules, polymers, fullerenes, nanotubes, graphene, other carbon-based molecular structures and hybrid materials. Actually these materials are being used to build electronic structures into electronic devices, like organic light-emitting diodes (OLEDs), organic solar cells (OSCs), and organic field-effect transistors (OFETs), constituting and already commercial reality. Some of them are used on a widespread basis1, and are the focus of some recent researches in molecules2,3 and polymers4-6 suitable for these purposes. In this study we analyze the electronic and molecular characteristics of some different π-conjugated structures in order to evaluate their potential as semiconducting materials for organic electronics. For this purpose we focus on the study of conjugated polymers with different backbones configurations: (i) donor-acceptor configuration, (ii) 1D lineal or 2D branched conjugated backbones, and (iii) encapsulated polymers. To achieve this goal, we use a combined experimental and theoretical approach that includes electronic spectroscopies (i.e., absorption, emission and microsecond transient absorption), vibrational Raman spectroscopy and DFT calculations. These structural modifications are found to provoke a strong impact on the HOMO and LUMO levels and the molecular morphology, and, consequently, on their suitability as semiconductors in organic electronic applications.References 1. S. R. Forrest, M. E. Thompson. Chem. Rev., 2007, 107, 923 2. R. C. González-Cano, G. Saini, J. Jacob, J. T. López Navarrete, J. Casado and M. C. Ruiz Delgado. Chem. Eur. J. 2013, 19, 17165 3. J. L. Zafra, R. C. González-Cano, M. C. Ruiz Delgado, Z. Sun, Y. Li, J. T. López Navarrete, J. Wu and J. Casado. J. Chem. Phys. , 2014, 140, 054706 4. M. Goll, A. Ruff, E. Muks, F. Goerigk, B. Omiecienski, I. Ruff, R. C. González-Cano, J. T. López Navarrete, M. C. Ruiz Delgado, S. Ludwigs. Beilstein J. Org. Chem., 2015, 11, 335. 5. D. Herrero-Carvajal, A. de la Peña, R. C. González-Cano, C. Seoane, J. T. López Navarrete, J. L. Segura, J. Casado, M. C. Ruiz Delgado, J. Phys. Chem. C, 2014, 118, 9899. 6. M. Scheuble, Y. M. Gross, D. Trefz, M. Brinkmann, J. T. López Navarrete, M. C. Ruiz Delgado, and S. Ludwigs, Macromolecules, 2015, 48, 7049.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Análisis del impacto de los fondos europeos 2007-2013 en Andalucía a través de un modelo de equilibrio general aplicado

Tras dos décadas en las que Andalucía ha sido objeto de la financiación europea, este trabajo propone un análisis del impacto económico de los Fondos Europeos recibidos por la Comunidad Autónoma de Andalucía en el septenio 2007-2013, para tratar de evaluar la incidencia de las ayudas sobre esta economía. Para ello se presenta un Modelo de Equilibrio General Aplicado (MEGA) estático, que evaluará, en diferentes escenarios de simulación, los efectos sobre los principales indicadores económicos. Los resultados pondrán de manifiesto la contribución significativa de los Fondos Europeos para el crecimiento de la región en el periodo analizado

Cyclic Triindoles and Tetraindoles: Substituent and Symmetry Effects on their Structural and Electronic Characteristics

During the last decade heptacyclic 10,15-dihydro-5H-diindolo[3,2-a:3',2'-c]carbazole (triindole) has been extensively studied as a new π-conjugated platform in the construction of self-assembling materials for optoelectronics. Specially remarkably is the record hole mobility values determined on triindole liquid crystals.1 In order to facilitate the design of new materials on a molecular basis and establish clear guidelines to fine tuning electronic parameters, we have recently synthesized new triindole and tetraindole-based systems.2-3 Our joint experimental and theoretical investigation shows that N-substitution, symmetry lowering of the platform, and insertion of π-spacers in extended dimers strongly impact on the fundamental electronic properties of triindoles.2 In addition, saddle-shaped tetraindoles are found to be an interesting 3D rigid scaffold to obtain electroactive molecules with increased dimensionality.3 We hope that this study can not only advance useful structure-property relationships of conjugated indole-based systems but also guide the design of new materials with potential applications in organic electronics.References 1. E.M. García-Frutos, U.K. Pandey, R. Termine, A. Omenat, J. Barberá, J.L. Serrano, A. Golemme, B. Gómez-Lor, Angew. Chem. Int. Ed. 2011, 50, 7399 2. a) C. Ruiz, J.T. López Navarrete, M.C.Ruiz Delgado, B. Gómez-Lor, Org. Lett. 2015, 17, 2258−2261. b) C. Ruiz, E.M. García-Frutos, D.A. da Silva Filho, J.T. López Navarrete, M.C. Ruiz Delgado, and B. Gómez-Lor, J. Phys. Chem. C 2014, 118, 5470−5477 3. C. Ruiz, A. Monge, E. Gutiérrez-Puebla, I. Alkorta, J. Elguero, J. T. López Navarrete, M.C. Ruiz Delgado and B. Gómez-Lor, submittedUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

The Structural Funds in Andalusia for the Programming Period 2014-20. Time for Tightening Belts

During the period 2014–2020 it will be the first time since Spain joined the European Economic Community that the Southern region of Andalusia will not be considered as one of the Objective 1 priority areas for the European Regional Policy. This paper analyses the economic impact of the foreseeable withdrawal of an important amount of European Structural Funds in the region. Our point is to develop a dynamic general equilibrium model to assess, under different simulation scenarios, the effects of the removal of this funding on the main regional economic indicators, specially focusing on GDP growth, a key variable for the future of the region

Novel U-Shaped D-A-D π-conjugated Systems with Mechanochromic Properties: An Experimental and Theoretical Vibrational Spectroscopic Investigation

Π-conjugated compounds have been widely studied in the last few decades due to their huge field of application in organic electronics. Specifically, stimuli-responsive Π-conjugated materials which are sensitive to external stimulus (i.e., temperature, pressure, etc) have several uses like sensors, probes and security inks, for example.1 In this work, we study two U-shape Donor-Acceptor-Donor (D-A-D) systems that are found to exhibit interesting thermal- and pressure-dependent properties. 2 They consist on two different conformers of phenothiazine-dibenzo[a,j]phenazine-phenothiazine which differs from the position of the phenothiazine respect to the dibenzophenzaine central core. Compound 1R is the equatorial-equatorial conformer and 1Y is the axial-axial conformer (Figure 1). The dibenzophenzaine group acts as an electron-acceptor whereas the phenothiazine unit acts as an electron-donor. It has been reported that this U-shape D-A-D compound shows a multi-active color changing in 3 steps and their luminescence changes with temperature, pressure and acid exposition.2 In this work, we aim to elucidate how the external stimuli (i.e. temperature, pressure, acid ambient) affects the molecular structure at both intra- and intermolecular level. To this end, we use UV-Vis absorption, Raman (Figure 1) and Infrared spectroscopy experiments in combination with DFT calculations.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Conductas de riesgo, consumo de sustancias y género

La preocupación por el consumo de sustancias entre los jóvenes ha llevado a gobiernos, educadores e investigadores a cuestionarse no sólo los efectos que las drogas tienen sobre los chicos y chicas, tanto a nivel físico y emocional, como sobre su desarrollo posterior y a poner en marcha mecanismos y recursos para la prevención. Esta investigación es fruto de la puesta en marcha de un programa de formación para mediadores juveniles financiado por distintos organismos de la Junta de Andalucía y que se integra en una planificación de intervención más amplia denominada “Proyecto Forma Joven”. Los resultados ponen de manifiesto la coincidencia entre nuestra población y los datos de la población general respecto a consumo, tipo de consumo, diferencias por géneros y relación con conductas de riesgo, aunque podemos encontrar algunos matices diferenciales, lo que propició un programa de formación más consistente con los datos concretos.Concerned by the effects of substances abuse on boys and girls physical and emotional development, governments, educators, and researchers are committed to improve preventive programs against drugs consumption. In the frame of a wide program of intervention (“Proyecto Forma Joven”), aimed to form young people as mediators in peers health education, and financed by several institutional programs of the government of Andalusia (Spain), this study provided a detailed description of the relations between gender, and patterns of substances consumption, in order to reach a better adjustment of the formation of the future mediators that will implement preventive programs

Understanding the structure-property correlations of n-type organic semiconductors in OFETs

In the organic electronic research field, the development of high-performance unipolar n-type semiconductors is still challenging. Here we present an in-depth study of a series of ladder-type semiconductors, which due to their all-acceptor backbones, exhibit unipolar n-type transport in OTFTs. It is well know that the performance of organic semiconductors is governed not only by their molecular structures but also by their intermolecular assembly in the solid state. Thus, highly planar backbones are beneficial for a good molecular packing and film ordering leading to good charge transport characteristics. In this contribution, we study a series of BTI small molecules and polymers, both from a molecular and from a supramolecular point of view, in order to establish useful structure-property relationships that may guide the rational synthesis of new and improved materials. To carry out this study, we make use of different spectroscopic techniques, supported by quantum theoretical calculations at the DFT level.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech