Studies on organic solar cells based on small-molecules : tetraphenyldibenzoperiflanthene and fullerene C70

This work deals with the research on organic solar cells based on small-molecules semiconductors. In particular, organic solar cells of this thesis have been used tetraphenyldibenzoperiflanthene as donor material and fullerene C70 as acceptor material. In the first part of this thesis, we focus on the influence of the density of states of the donor layer on the characteristic parameters of solar cells. Further, organic solar cells with p-i-n structure are presented, where the intrinsic layer is obtained by coevaporation of donor and acceptor. The influence of the thickness of the intrinsic layer on the p-i-n solar cell characteristic is analysed. In the second part, an equivalent circuit for organic solar cells is presented. A new term is added to the standard model representing recombination losses in the active layer of the device. The analysis of the characteristics of current - voltage measured at different illumination intensities allows the estimation of the term recombination. The model clearly separates technological issues (series and parallel resistance) from effects related to the physics of the device (recombination losses). It also allows obtaining an effective mobility-lifetime product in the active layer of the device to be determined, characterising its state of degradation.En aquesta tesi s’investiguen cèl·lules solars orgàniques basades en semiconductors de petita molècula. En particular, les cèl·lules solars orgàniques d’aquesta tesi han emprat tetraphenyldibenzoperiflanthene com material donador i ful·lerè C70 com material acceptador. En la primera part d'aquesta tesi, ens centrem en la influència de la densitat d'estats de la capa donadora en els paràmetres característics de les cèl·lules solars. Més endavant, es presenten cèl·lules solars orgàniques amb una estructura p-i-n, on la capa intrínseca s'obté per l'evaporació conjunta del donador i l’acceptador. S'analitza la influència del gruix de la capa intrínseca de la cèl·lula solar p-i-n en la característica de la cèl·lula solar. En la segona part, es presenta un circuit equivalent per a les cèl·lules solars orgàniques. S'afegeix un nou terme en el model estàndard que representa les pèrdues de recombinació a la capa activa del dispositiu. L’anàlisi de les característiques de corrent-tensió mesurades a diferents intensitats de llum permeten l'estimació del terme de recombinació. El model separa clarament les qüestions tecnològiques (resistències en sèrie i en paral·lel) dels efectes relacionats amb la física del dispositiu (pèrdues de recombinació). També permet l’obtenció d’un producte de la mobilitat - temps de vida efectiu a la capa activa del dispositiu a ser determinat, la caracterització del seu estat de degradació

Deposition of composite materials using a wire-bar coater for achieving processability and air-stability in Organic Field-Effect Transistors (OFETs)

Organic thin films based on composite materials of semiconducting dibenzo-tetrathiafulvalene (DB-TTF) and insulating styrenic matrices (Polystyrene (PS10k) and Poly-alpha methylstyrene (PAMS10k) ) have been fabricated by the wire-bar coating technique in ambient conditions (air, light, humidity) and contrasted with the ones prepared by thermally evaporating the organic semiconductor. The transistors fabricated with DB-TTF:PS10k composites show a clear fieldeffect behavior with p-type characteristics, exhibiting charge carriers mobilities in the range of 0.01 cm2/Vs, fully comparable with the films obtained by thermal evaporation. However, while the thermally evaporated films show poor stability in air, the wire-bar coated composites films and devices are highly reproducible and exhibit lower threshold voltage values. Thus, we demonstrate the suitability of the wire-bar technique for manufacturing large area devices.The authors thank the ERC StG 2012-306826 e-GAMES project, the Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), the DGI (Spain) with project BE-WELL CTQ2013-40480-R, and the Generalitat de Catalunya (2014-SGR-17). F. G. D. P. thanks Universidad Técnica de Ambato and Secretaría de Educación Superior, Ciencia, Tecnología e Innovación for funding through a doctoral scholarship “Convocatoria abierta 2010”.Peer Reviewe

A Rapid, Low-Cost, and Scalable Technique for Printing State-of-the-Art Organic Field-Effect Transistors

In the last few years exciting advances have been achieved in developing printing techniques for organic semiconductors, and impressive mobility values have been reported for the resulting organic field-effect transistors (OFETs). However, not all these techniques are scalable and some of them require additional crystallization steps. This study reports on the fabrication of OFETs employing blends of four benchmark organic semiconductors with polystyrene and demonstrates that applying the same formulation and experimental conditions for printing them, highly reproducible and uniform crystalline films exhibiting high OFET performance are successfully achieved. It is noted that the mobility values achieved here are not the highest reported for the studied materials; however, they are state-of-the-art values and could be regarded as exceptional considering the low cost and fast speed of the fabrication process involved here.This work was mainly funded by the ERC StG 2012 306826 e GAMES and ERC PoC 2014 640120 LAB TECH projects. The authors also thank the Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER BBN), the DGI (Spain) project BE WELL CTQ2013 40480 R, the Generalitat de Catalunya (2014 SGR 17) and the Spanish Ministry of Economy and Competitiveness, through the “Severo Ochoa” Programme for Centres of Excellence in R&D (SEV 2015 0496). The authors would like to thank the ICTS "NANBIOSIS", more specifically to the Nanotechnology Platform, unit of CIBER BBN at the Institute for Bioengineering of Catalonia (IBEC) for their assistance in ToF SIMS analyses. I. T. acknowledges FPU fellowship from the Ministery and the Materials Science PhD Program of Universitat Autònoma de Barcelona. F. G. D. P. thanks Universidad Técnica de Ambato and Secretaría de Educación Superior, Ciencia, Tecnología e Innovación for funding through a doctoral scholarship “Convocatoria abierta 2010”.Peer reviewe

Single Crystal-Like Performance in Solution-Coated Thin-Film Organic Field-Effect Transistors

In electronics, the fi eld-effect transistor (FET) is a crucial cornerstone and successful integration of this semiconductor device into circuit applications requires stable and ideal electrical characteristics over a wide range of temperatures and environments. Solution processing, using printing or coating techniques, has been explored to manufacture organic fi eld-effect transistors (OFET) on fl exible carriers, enabling radically novel electronics applications. Ideal electrical characteristics, in organic materials, are typically only found in single crystals. Tiresome growth and manipulation of these hamper practical production of fl exible OFETs circuits. To date, neither devices nor any circuits, based on solution-processed OFETs, has exhibited an ideal set of characteristics similar or better than today’s FET technology based on amorphous silicon. Here, bar-assisted meniscus shearing of dibenzo-tetrathiafulvalene to coat-process self-organized crystalline organic semiconducting domains with high reproducibility is reported. Including these coatings as the channel in OFETs, electric fi eld and temperature-independent charge carrier mobility and no bias stress effects are observed. Furthermore, record-high gain in OFET inverters and exceptional operational stability in both air and water are measured.The authors thank the ERC StG 2012-306826 e-GAMES project, the Networking Research Center on Bioengineering, Biomaterials, and Nanomedicine (CIBER-BBN), the DGI (Spain) project BE-WELL CTQ2013-40480-R, and the Generalitat de Catalunya (2014-SGR- 17). Research in Sweden was fi nancially supported by the Advanced Functional Materials Center at Linköping University, the Önnesjö Foundation, the Knut and Alice Wallenberg Foundation (Power Paper project, scholars), the Swedish Foundation for Strategic Research (SSF, Synergi project). F.G.D.P. thanks Universidad Técnica de Ambato and Secretaría de Educación Superior, Ciencia, Tecnología e Innovación for funding through a doctoral scholarship “Convocatoria abierta 2010.” The authors also thank Witold Tatkiewicz for his help with the ImageJ software.Peer reviewe

A rapid, low-cost, and scalable technique for printing state-of-the-art organic field-effcet transistors

In the last few years exciting advances have been achieved in developing printing techniques for organic semiconductors, and impressive mobility values have been reported for the resulting organic field-effect transistors (OFETs). However, not all these techniques are scalable and some of them require additional crystallization steps. This study reports on the fabrication of OFETs employing blends of four benchmark organic semiconductors with polystyrene and demonstrates that applying the same formulation and experimental conditions for printing them, highly reproducible and uniform crystalline films exhibiting high OFET performance are successfully achieved. It is noted that the mobility values achieved here are not the highest reported for the studied materials; however, they are state-of-the-art values and could be regarded as exceptional considering the low cost and fast speed of the fabrication process involved here.Peer ReviewedPostprint (published version

Ruta verde y Plan S en la Universitat Politècnica de València

El objetivo principal del Plan S es hacer que la información financiada con fondos públicos esté en Acceso Abierto inmediatamente tras su publicación. Para ello se establecen tres rutas diferentes: publicación en revistas de Acceso Abierto, depósito en repositorios y publicación en revistas a través de acuerdos transformativos. Hasta ahora, la tendencia en Europa es la negociación de acuerdos transformativos entre las editoriales y las instituciones, que normalmente llevan aparejados un sobrecoste respecto al modelo de suscripción. Sin embargo, en España se lleva apostando desde hace tiempo por la ruta verde para alcanzar el Acceso Abierto a las publicaciones científicas. Es muy probable que se establezca en las negociaciones, un escenario para el cumplimiento del Plan S basado en el depósito inmediato en Acceso Abierto de la versión aceptada tras el proceso de revisión o la versión editorial a través de repositorios. Resulta, por tanto, imprescindible conocer la situación actual de los repositorios institucionales de cara a futuras negociaciones con las editoriales. Por ejemplo, ¿qué sentido tendría asumir un sobrecoste para eliminar el embargo si el depósito de un artículo en un repositorio tiene una demora de varios meses? Por este motivo, se ha analizado el repositorio institucional de la UPV (Riunet) respondiendo a varias preguntas: ¿se cumple con los requisitos técnicos del Plan S?, ¿están depositados todos los trabajos financiados por la Comisión Europea y/o por agencias de carácter público?, ¿cuál es el tiempo de demora entre la publicación del trabajo y el depósito en el repositorio

Effects of Cannabis Use on the Protein and Lipid Profile of Olfactory Neuroepithelium Cells from Schizophrenia Patients Studied by Synchrotron-Based FTIR Spectroscopy.

Schizophrenia (SCZ) is a neurodevelopmental disorder with a high genetic component, but the presence of environmental stressors can be important for its onset and progression. Cannabis use can be a major risk factor for developing SCZ. However, despite the available data on the neurobiological underpinnings of SCZ, there is an important lack of studies in human neuronal tissue and living cells addressing the effects of cannabis in SCZ patients. In this study, we analysed the most relevant bio-macromolecular constituents in olfactory neuroepithelium (ON) cells of healthy controls non-cannabis users, healthy cannabis users, SCZ patients non-cannabis users, and SCZ patients cannabis users using Synchrotron Radiation-Fourier Transform Infrared (SR-FTIR) spectrometry and microscopy. Our results revealed that SCZ patients non-cannabis users, and healthy cannabis users exhibit similar alterations in the macromolecular profile of ON cells, including disruption in lipid composition, increased lipid membrane renewal rate and lipid peroxidation, altered proteins containing more β-sheet structures, and showed an increase in DNA and histone methylation. Notably, these alterations were not observed in SCZ patients who use cannabis regularly. These data suggest a differential effect of cannabis in healthy controls and in SCZ patients in terms of the macromolecular constituents of ON cells

Large Stokes shift downshifting Eu(III) films as efficiency enhancing UV blocking layers for dye sensitized solar cells

Large Stokes shift downshifting organolanthanide complex, Eu(tta)(3)phen, is examined for inclusion in polymeric layers to replace the UV blocking layer in dye sensitized solar cell (DSSC) technology. The UV blocking layer increases stability but power conversion efficiency decreases as incident UV photons are not converted into photocurrent. Eu(tta) 3phen doped polymeric film are prepared and attached to DSSC devices following optimized thickness and concentration from a ray-trace numerical model for the specific DSSC. External quantum efficiency is significantly increased in the UV spectral region compared to DSSCs utilizing a passive, non-luminescent, UV-BL. High Eu(tta)(3)phen film transparency in the visible range minimizes DSSC EQE losses at visible wavelengths. Short-circuit current (I-sc) enhancement due to downshifting is demonstrated (similar to 1%) in small-scale DSSC prototypes, where the specific geometry limits the photon collection efficiency and overall enhancement. Model predictions indicate that 2%-3% I-sc enhancement is realizable in flexible single DSSC compared to, non-luminescent, UV-BL. Added to this, in outdoor conditions taking into account diffuse light, the increment in Isc can increase 50% more. Although photostability of the blended LSS-DS polymer films is not sufficient to be useful for medium-long term outdoor PV applications, the results demonstrate that significant efficiency enhancement can be realized. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimPeer ReviewedPostprint (author’s final draft

IVO Robot: a new social robot for human-robot collaboration

© 2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.We present a new social robot named IVO, a robot capable of collaborating with humans and solving different tasks. The robot is intended to cooperate and work with humans in a useful and socially acceptable manner to serve as a research platform for long-term Social Human-Robot Interaction. In this paper, we proceed to describe this new platform, its communication skills and the current capabilities the robot possesses, such as, handing over an object to or from a person or performing guiding tasks with a human through physical contact. We describe the social abilities of the IVO robot, furthermore, we present the experiments performed for each robot's capacity using its current version.Peer ReviewedPostprint (author's final draft

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field