Efecto de la nanotecnología en la capa activa de dispositivos fotovoltaicos utilizando derivados de porfirinas

La nueva generación de fotovoltaicas tiene un enfoque alternativo y complementario para la explotación de la energía solar, con bajo coste de fabricación, felixibilidad, transparencia y peso ligero. Las células solares más prometedoras por su notable progreso son las células solares orgánicas (OSC), células solares sensibilizadas por colorante (híbridas) y células solares de perovskita. Las porfirinas, que son análogos sintéticos de las clorofilas naturales, son de especial interés, debido a su elección natural como sistemas de antenas de recolección de luz que participan en procesos de transferencia de energía y electrones. En los últimos años, ha habido un gran interés en el campo de las células solares orgánicas de heterounión masiva (BHJ) procesadas en disolución utilizando derivados de porfirina como dadores y derivados de fulereno como aceptores, presentando resultados de PCE del 9.06%. En este trabajo se presenta la síntesis y propiedades de derivados de porfirinas A-D-A y el efecto dela capa activa de tamaño nanométrico utilizando diferentes proporciones con PCBM como aceptor alcanzando eficiencias superiores al 8%

New cyclopentadithiophene (CDT) linked porphyrin donors with different end-capping acceptors for efficient small molecule organic solar cells

The synthesis of two new A-π-D-π-A molecules bearing a Zn-porphyrin core donor linked through cyclopenta[2,1-b:3,4- b’]dithiophene bridges to the electron-acceptor rhodanine (SA1) or dicyanovinylene (SA2) groups is described. The optical and electrochemical properties of these compounds are investigated. The horizontal conjugation of cyclopentadithiophene between the porphyrin core and the end-capping acceptor not only effectively increases the light harvesting between the Soret and Q bands of the porphyrin unit, but also optimizes the molecular packing through linear -conjugated backbones. Compounds SA1 and SA2 are employed as donors along with [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as an acceptor in organic bulk heterojunction organic solar cells. After optimizing the processing of the active layer (a solvent additive and subsequent solvent vapor annealing), overall power conversion efficiencies of 6.94% and 8.19% (with low energy loss of 0.55 eV) are obtained for the organic solar cells. The use of a solvent additive and subsequent solvent vapor annealing provide enhanced nanoscale morphology and the bi-continuous interpenetrating networks in the active layer required for efficient exciton dissociation into free charge carriers and their subsequent transportation towards electrodes. This change let to higher PCE values when compared to devices based on as-cast active layers

High Photo-Current in Solution Processed Organic Solar Cells Based on Porphyrin Core A-π-D-π-A as Electron Donor Material

Two new conjugated acceptor-donor-acceptor (A-p-D-p-A) molecules with a porphyrin core linked by ethynylene bridges to two thiophene (1a) or thienylenevinylenethiophene (1b) units and both capped by N-ethylrhodanine have been synthesized. These compounds were used as the main electron donor moieties for bulk heterojunction small molecule organic solar cells (BHJ-SMOSC). The optimized devices, with PC71BM as the main electron acceptor molecule, show remarkable short circuit currents, up to 13.2 mA/cm2, an open circuit voltage of around 0.85 V, and power conversion efficiencies up to 4.3% under 100 W/cm2. The External Quantum Efficiency (EQE), Atomic Force Microscopy (AFM), hole mobility, Photo-Induced Charge Extraction (PICE) and Photo-Induced Transient Photo-Voltage (PIT-PV) were analyzed in devices based on 1a and 1b in order to account for differences in the final performance of the two molecules. The PIT-PV decays showed slower recombination kinetics for devices fabricated with 1b. Moreover, the EQE was greater for 1b and this is ascribed to the better nanomorphology, which allows better charge collection before carrier recombination takes place

Novel porphyrins for DSSC and BHJ solar Cells

The global challenge of sustainable development, clean energy and climate change needs to be pursued by development of energy technologies. Moreover the energy sector is responsible of two thirds of the world’s greenhouse-gas (GHG) emissions ; therefore the world needs to change the inefficient energy system based on fossil fuels to renewable sources as sunlight, wind, rain, waves, tides, biomass and geothermal heat. Besides solar energy is available throughout the world as radiant light or heat from the sun, using technology such as photovoltaics devices. New generation of photovoltaics can provide an alternative and complementary approach for the exploitation of solar energy; offers low manufacture cost, they are flexible, light, and more environmental friendly; the most promising for their remarkable progress are: organic solar cells, hybrid dye sensitized solar cells, and perovskite solar cells. Nevertheless, in this thesis the first two types of cells will be widely described focusing on devices comprising porphyrins, these molecules have been explored due to their robustness, thermal stability, rich metal coordination chemistry, strong aromaticity, optical, electronic and magnetic properties. Content In the first chapter twelve novel small molecule porphyrins, with configuration A-?-D-?-A, were synthesized and characterized to be applied in solution processed bulk heterojunction solar cells (BHJSC). Also zinc porphyrin core (D) and ? conjugated linker were separated by an ethynyl group, to improve the planarity and enhance the ? conjugation of the system. Moreover each molecule comprise two strong ? electron withdrawing moieties (A) to control the absorption spectrum in the near infrared region, by a conjugation with electron rich aromatic units. In order to study, all molecules were synthesized and properly characterized, photophysical and electrochemical properties were measured, and theoretical HOMO-LUMO orbitals and optimized geometries were calculated. Additionally, to complete these studies, devices performance was evaluated and the best PCE (4.24%) was achieved with PC71BM:SA4 (4:1 w/w) (comprising a mesityl zinc porphyrin core, (E)-1,2-bis(3,4-dihexylthiophen-2-yl)ethylne as ? conjugated linker and 3-ethylrhodanine as acceptor), with a high short circuit current (JSC) of 13.2 mAcm-2. In the second chapter six novel dyes bearing triphenylamine donor groups were synthesized and characterized. The absorption and electrochemical properties were investigated to determine the electronic features of these compounds. Moreover these molecules were employed as sensitizer for Dye Sensitized Solar Cells (DSSCs), and their efficiencies were measured in nanocrystalline TiO2. The best PCE (6%) was achieved for SA12 employing two thiophene rings connected by a double bond as spacers between the conjugated porphyrin core and the anchoring cyanoacrylate group. Novel designs of porphyrin and improvements in photovoltaic devices can be achieved. Therefore, there is still much work to be done to improve solar cells. Moreover, in the last years the research on this thematic is allowing to develop best photovoltaics

Nanopartículas de dióxido de titanio y aditivo hidrofóbico para mejorar las propiedades de auto-limpieza de morteros de recubrimientos

Nuevos morteros de textura lisa con propiedades hidrofóbicas y de autolimpieza han sido desarrollados utilizando nanopartículas de dióxido de titanio y silicona de polisioloxano (TiO2/Si). La fotocatálisis heterogénea de TiO2 es una estrategia eficiente para obtener superficies autolimpiadoras en los morteros de recubrimiento y el Si aporta propiedades hidrofóbicas. Se caracterizaron las nanopartículas de TiO2 con difracción de rayos X y se analizaron los morteros utilizando diferentes proporciones de TiO2 0.5, 1, 3 y 0.5% de Si, la fase de mezclado mecánico se realizó acorde a la norma ASTM C 305-12. El estudio de termogravimetría identificó los hidratos presentes en la matriz y la temperatura de descomposición siendo esta mayor de 600°C para todas las muestras. Se evaluó la actividad fotocatalítica heterogénea utilizando un análisis colorimétrico y la exposición a radiación ultravioleta, para la degradación del colorante orgánico rodamina B. A edades tempranas de curado las probetascon adición de 1%TiO2-0.5%Si obtuvieron mejores resultados de degradación de color. A edades tardías de curado (28 días) se observó una disminución en la actividad fotocatalítica de las muestras. Se determinaron las propiedades hidrofóbicas del mortero, mediante un análisis de ángulo de contacto y permeabilidad utilizando el tubo de Karsten. Este estudio demuestra que los morteros que contienen TiO2-Si presentan propiedades autolimpiantes y propiedades humectantes que favorecen la limpieza de partículas sueltas con el agua de lluvia.</p

Efecto de la nanotecnología en la capa activa de dispositivos fotovoltaicos utilizando derivados de porfirinas

La nueva generación de fotovoltaicas tiene un enfoque alternativo y complementario para la explotación de la energía solar, con bajo coste de fabricación, felixibilidad, transparencia y peso ligero. Las células solares más prometedoras por su notable progreso son las células solares orgánicas (OSC), células solares sensibilizadas por colorante (híbridas) y células solares de perovskita. Las porfirinas, que son análogos sintéticos de las clorofilas naturales, son de especial interés, debido a su elección natural como sistemas de antenas de recolección de luz que participan en procesos de transferencia de energía y electrones. En los últimos años, ha habido un gran interés en el campo de las células solares orgánicas de heterounión masiva (BHJ) procesadas en disolución utilizando derivados de porfirina como dadores y derivados de fulereno como aceptores, presentando resultados de PCE del 9.06%. En este trabajo se presenta la síntesis y propiedades de derivados de porfirinas A-D-A y el efecto dela capa activa de tamaño nanométrico utilizando diferentes proporciones con PCBM como aceptor alcanzando eficiencias superiores al 8%.</p

Methodology for Monitoring Sustainable Development of Isolated Microgrids in Rural Communities

Microgrids are a rapidly evolving and increasingly common form of local power generation used to serve the needs of both rural and urban communities. In this paper, we present a methodology to evaluate the evolution of the sustainability of stand-alone microgrids projects. The proposed methodology considers a composite sustainability index (CSI) that includes both positive and negative impacts of the operation of the microgrid in a given community. The CSI is constructed along environmental, social, economic and technical dimensions of the microgrid. The sub-indexes of each dimension are aggregated into the CSI via a set of adaptive weighting factors, which indicate the relative importance of the corresponding dimension in the sustainability goals. The proposed methodology aims to be a support instrument for policy makers especially when defining sound corrective measures to guarantee the sustainability of small, isolated microgrid projects. To validate the performance of the proposed methodology, a microgrid installed in the northern part of Chile (Huatacondo) has been used as a benchmarking project

Análisis y valoración de la influencia que ejerce el perfil formativo de los entrenadores en jóvenes futbolistas

The aim of this research is to analyze and assess the formative profile of football coaches, based on Nicholls� Goal Theory (1984), Bandura�s Self-efficiency Theory (1986) and Deci and Ryan�s Self Determination Theory (1985). We selected three coaches from the lower categories of Real Sociedad S.A.D. and 4 players (aged 15 to 19) from each of their teams. We selected the players depending on the time they participated in the competition, to represent the footballers that play almost every minute, the ones that play around 75% of the minutes and the ones who play the smallest amount of minutes (more or less 50%). At the end of the season, these players filled in the questionnaire of Perceived Formative Climate, which involves four different variables (Motivational Climate, Trust in the players, Communication and Decisional style). The results we obtained show that there are significant differences (pd».05) in the perception of players with regard to the formative climate of their coaches. Specifically, we found these differences in four of the seven dimensions composing the formative climate (Individual Mastery Climate, Emotional Communication, Decisional Style and Reactive Communication). These results emphasize how important are coach�s criteria and the way he/she communicates with players regarding the formative quality and sports experience. Moreover, these conclusions also suggest that it is necessary to tackle it from a multidimensional perspective to be able to analyze it in depth and within the context.El objetivo de esta investigación es el de analizar y valorar el perfil formativo de los entrenadores de fútbol, basado en la Teoría de Metas de Nicholls (1984), en la Teoría de Autoeficacia de Bandura (1986) y en la Teoría de Autodeterminación de Deci y Ryan (1985). Se seleccionaron tres entrenadores de las categorías inferiores de la Real Sociedad S.A.D. y 4 jugadores (de 15 a 19 años) de cada uno de sus equipos. La selección de estos jugadores se hizo en función del tiempo de participación en competición, para representar a los jugadores que disputan prácticamente todos los minutos de competición, a los que disputan alrededor del 75 % de los minutos y a los que menos minutos disputan (en torno al 50%). Al final de la temporada realizaron el cuestionario de Clima Formativo Percibido, que contempla cuatro variables (Clima Motivacional, Confianza en los jugadores, Comunicación y Estilo Decisional). Los resultados obtenidos indican que existen diferencias significativas (pd».05) en la percepción de los jugadores respecto al clima formativo de sus entrenadores. Concretamente, estas diferencias se encuentran en cuatro de las siete dimensiones que componen el clima formativo (Clima de Maestría Individual, Comunicación Afectiva, Estilo Decisional y Comunicación Reactiva). Estos resultados destacan la importancia que tienen los criterios y la forma de comunicarse del entrenador con los jugadores en relación a la calidad formativa de la experiencia deportiva y además, sugieren que, para analizarla en el contexto con una adecuada profundidad, es necesario abordarlo desde una perspectiva multidimensional

Analysis and assessment of the influence coaches’ formative profile has on young footballers

The aim of this research is to analyze and assess the formative profile of football coaches, based on Nicholls’ Goal Theory (1984), Bandura’s Self-efficiency Theory (1986) and Deci and Ryan’s Self Determination Theory (1985). We selected three coaches from the lower categories of Real Sociedad S.A.D. and 4 players (aged 15 to 19) from each of their teams. We selected the players depending on the time they participated in the competition, to represent the footballers that play almost every minute, the ones that play around 75% of the minutes and the ones who play the smallest amount of minutes (more or less 50%). At the end of the season, these players filled in the questionnaire of Perceived Formative Climate, which involves four different variables (Motivational Climate, Trust in the players, Communication and Decisional style). The results we obtained show that there are significant differences (pd».05) in the perception of players with regard to the formative climate of their coaches. Specifically, we found these differences in four of the seven dimensions composing the formative climate (Individual Mastery Climate, Emotional Communication, Decisional Style and Reactive Communication). These results emphasize how important are coach’s criteria and the way he/she communicates with players regarding the formative quality and sports experience. Moreover, these conclusions also suggest that it is necessary to tackle it from a multidimensional perspective to be able to analyze it in depth and within the contex

CuSCN as Selective Contact in Solution Processed Small Molecule Organic Solar Cells Leads to over 7% Efficient Porphyrin Based Device

Two conjugated acceptor?p?donor?p?acceptor (A?p?D?p?A) small molecules with a zinc porphyrin donor core and 3-ethylrhodanine terminal acceptors connected at the meso positions by ethynylene groups and linked by one or two thienylenevinylene units denoted by 1a and 1b were synthesized and their optical and electrochemical properties were investigated. Bulk heterojunction organic solar cells fabricated with 1a : PC71BM and 1b : PC71BM processed with THF exhibited power conversion efficiencies of 2.75% (Jsc = 7.96 mA cm-2, Voc = 0.96 V and FF = 0.36) and 3.18% (Jsc = 8.84 mA cm-2, Voc = 0.90 V and FF = 0.40), respectively. Moreover, organic solar cells based on 1a : PC71BM and 1b : PC71BM processed with pyridine/THF solution displayed PCEs of 5.27% (Jsc = 10.61 mA cm-2, Voc = 0.92 V and FF = 0.54) and 5.78% (Jsc = 11.58 mA cm-2, Voc = 0.86 V and FF = 0.58), respectively. However, most important is the observation that the PCE was further increased to 7.24% for devices based on 1a : PC71BM and 1b : PC71BM active layers processed with pyridine/THF solution by employing CuSCN as a selective contact electrode instead of the most common hole transport material, namely, PEDOT:PSS