Is the exchange rate an adjustment mechanism?.

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Formación de nuevas estructura moleculares en películas ultrafinas.Preparación de dispositivos electroluminiscentes y fotovoltaicos

The evolution of technology has to meet the energetically needs of actual societies and be respectful for the environment through a sustainable and efficient use of energy. In this context organic electronic represents a promising technology. Organic semiconductors are abundant, easy to fabricate and their properties can be easily tuned. In the form of thin films, they exhibit interesting electronic and magnetic properties, which in many cases result from the specific molecular organization and interactions of their components. A low cost organic alternative to the classical lighting systems are the light-emitting electrochemical cells (LECs),. They require only one ionic emitting layer, are processed at ambient conditions and are compatible with air stable electrodes, avoiding rigorous encapsulation in inert atmosphere. Recently, LECs have shown high luminance, high efficiencies and relatively high stabilities when specific emitters were used. However, their slow response, their selflimiting nature and the absence of efficient white light emission, remain the limitations preventing their application in general lighting. On the other hand, organic thin films can also be used in photovoltaics, which represents an abundant and low cost alternative to the silicon established solar cell technology. Nevertheless, their record efficiency (~ 12%) is still below the requirements for a massive application. This suggests the need of new materials and configurations to achieve efficiencies close to those obtained in inorganic Si-cells (20 - 25%) but reducing the manufacturing costs. In this Thesis, thin films are studied from two different points of view: as organized ultra-thin systems containing UV-Vis absorbing molecules, frequently used in many optoelectronic devices; and as interlayers in LECs and OPV devices. In the first case, two superficial techniques, the Brewster Angle Microscopy and the UV-Vis Reflection Spectroscopy, are studied in order to obtain useful information from such highly organized systems. A new detailed description of the theoretical treatment needed for each technique is presented, which provides, through a relatively simple..

Efficient photovoltaic and electroluminescent perovskite devices

Planar diode structures employing hybrid organic-inorganic methylammonium lead iodide perovskites lead to multifunctional devices exhibiting both a high photovoltaic efficiency and good electroluminescence. The electroluminescence strongly improves at higher current density applied using a pulsed driving method

On the austerity policies in the Eurozone: What can we learn after the crisis?.

In the Eurozone, the financial crisis effects have been hit countries in a different manner. Austerity policies have not been good for everyone and have caused inequality in some groups. Some countries of the periphery have showed more vulnerable, producing alarming figures on output decreases and unemployment increases, particularly those of young unemployment. This compromise the inter-generational aspects of sustainable growth and development. In this paper, we consider an economic framework featuring the use of monetary and fiscal rules within a monetary union. In this scenario, that should be representative of the Eurozone, we will analyse the effects of stabilization policies when dealing with a financial crisis having contractive effects on output. Using data provided by Eurostat, we will perform an empirical application for three sets of European countries: the core, the peripheral, and the Eastern countries. In our analysis, we will also differentiate countries according with their historical unemployment path. We will show the results of stabilization fiscal policies by the supply-side, in terms of output and young unemployment before the crisis, 2007, and ten years later, 2017. The exercises will be performed under different degrees of conservativeness of the central bank, austerity of the fiscal authorities and different levels of public debt. Our results could help us to stablish the conditions under which stabilization policies have would lead to a less inequality outcomes.pre-print1033 K

Algumas chaves políticas para pensar na dor em tempos de dor

This is an article of reflection, proposing a biographical and event-based approach to the phenomenon of pain. In the discussions that are developed here, pain is understood as a referent of spatiotemporal action that transcends the traditional concepts and places of pain in a corporeality that requires physical and moral understanding. The arguments derived from the discussion invite to think about pain from both the personal experience and the shared experience, and opens the question as to whether such experiences are a platform for political action.Este artículo de reflexión propone una aproximación acontecimental y biográfica sobre la categoría del dolor. En las discusiones que aquí se desarrollan, esta categoría es comprendidacomo un referente de acción espaciotemporal, cuanto que trasciende las concepciones tradicionales y sitúa al dolor en una corporalidad que precisa de su comprensión física y moral. Los argumentos derivados de la discusión invitan a pensar en el dolor, tanto desde la experiencia personal como desde la experiencia compartida y abren la pregunta respecto a si dicha experiencia se constituye en una plataforma de acción política.Este artigo de reflexão propõe uma perspetiva biográfica e como acontecimento sobre a categoria da dor. Nas discussões desenvolvidas no presente artigo, esta categoria é compreendida como um referencial de ação espaço-temporal, desse modo, transcende as concepções tradicionais e situa a dor em uma corporalidade que exige sua compreensão física e moral. Os argumentos derivados da discussão convidam a pensar na dor tanto a partir da experiência pessoal como a partir da experiência compartilhada, e deixam em aberta a questão de se esta vivência se constitui em uma plataforma de ação política

Dispositivos optoelectrónicos basados en perovskitas orgánico-inorgánico conteniendo el catión guanidinio

La presente investigación se enfoca en el campo de dispositivos optoelectrónicos, concretamente en células solares basadas en perovskitas hibrídas orgánicas-inorgánicas, las cuales han emergido recientemente como un material prometedor para complementar o reemplazar a las actuales células solares basadas en silicio (Si). Los investigadores del Departamento de Química Física y Termodinámica Aplicada/ Instituto de Química Fina y Nanoquímica (UCO) en colaboración con el Group of Molecular Engineering of Functional Materials (EPFL) han logrado introducir el catión Guanidinio (Gua) en la red cristalina de la perovskita MAPbI3, basada en metilamonio (MA) y yoduro de plomo (PbI2), sustituyendo hasta un 25% de MA por Gua. Estos resultados son sorprendentes debido a que el radio catiónico del Guanidinio está por encima del límite de tolerancia de Goldsmith (0.8-1), el cual predice la formación de una estructura cristalina cubica. Este nuevo material GuaxMA(1-x)PbI3 (0 ≤ x ≤ 0.25) presenta una mayor estabilidad a la humedad y al oxígeno que su antecesor el MAPbI3. Además, conserva sus propiedades ópticas, las cuales fueron verificadas al fabricar células solares de alta eficiencia (hasta un 20%) y sometiéndolas a un test de estrés de mil horas bajo iluminación constante y a una temperatura de 65ºC (equivalente a 1333 días bajo condiciones normales). Este hallazgo abre la puerta a la incorporación de nuevas especies con radios catiónicos que excedan el límite teórico de Goldsmith

Efficient Semitransparent Perovskite Solar Cells Based on Thin Compact Vacuum Deposited CH3NH3PbI3 Films

Lead halide perovskite materials are promising candidates for the application of semitransparent solar cells due to their bandgap tunability and high device efficiencies. The high absorption coefficient of these materials, however, makes it difficult to attain high average visible transmittance values without compromising the power conversion efficiencies (PCEs). In this work, a co-evaporation process is employed to fabricate thin (50 and 100 nm) methylammonium lead iodide (MAPI) perovskite films and integrate them in semitransparent perovskite solar cells (ST-PSCs). Due to the compact nature of the thin MAPI films, the resultant fully vacuum and room temperature-processed devices demonstrate high fill factor values approaching 80% and open-circuit voltage values close to 1100 mV. As a result of this, the ST-PSCs exhibit PCE's as high as 9% with a photopic average visible transmittance of the full device of 23%

Effectiveness of mixtures of vivianite and organic materials in preventing iron chlorosis in strawberry

Application of Fe salts with different organic matter sources has been demonstrated to be effective in preventing Fe deficiency chlorosis. The main objective of this work was to study the effectiveness of different Fe sources based on mixtures of humic substances or compost with vivianite in preventing this nutritional disorder in strawberry (Fragaria × ananassa cv Camarosa). To this end, a randomised block experiment involving four replications (3 plants per replication) and one factor (Fe source) was performed in a greenhouse using a calcareous growing medium. Iron sources studied were: (i) control without Fe, (ii) control with an effective Fe source in calcareous media (EDDHA-Fe, 0.1 g kg–1), (iii) vivianite (1 g kg–1 medium, which is the recommended rate), (iv) vivianite (1 g kg–1) + humic substances (HS 0.06 g kg–1), (v) vivianite (0.5 g kg–1) + HS (0.06 g kg–1) and (vi) a mixture of composted cork residue and vivianite at a 6:1 mass ratio (CORVIV) applied at a dose of 6 g kg–1 medium. All Fe sources were effective in increasing SPAD readings when compared with control without Fe. Treatments based on vivianite provided non-significantly different SPAD readings from that obtained with EDDHA-Fe. However, only CORVIV showed non-significantly different dry matter (DM) production, leaf area index, and total Fe content in the aerial part than EDDHA-Fe. Humic substances and vivianite at 1 g kg–1 increased DM yield in plants when compared with vivianite without HS, results with this last treatment being similar to those obtained with vivianite at 0.5 g kg–1 with HS. It can be concluded that studied sources of organic matter increased the efficiency of vivianite in preventing Fe chlorosis in strawberry, especially vivianite enriched cork compost which was as effective as EDDHA-Fe

Diodos orgánicos emisores de luz: estrategias para la optimización de dispositivos y la obtención de un oled blanco

III Encuentro sobre Nanociencia y Nanotecnología de Investigadores y Tecnólogos Andaluce