4 research outputs found

    Interplay between microstructure/morphology and the opto-electronic properties of materials for organic photovoltaics.

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    216 p.Esta tesis recoge un amplio marco de trabajo que incluye la relación microestructura-procesado-morfología-propiedades de un sistema modelo de alto rendimiento en fotovoltaica orgánica. En primer lugar, la tesis aborda las cuestiones críticas que rodean la microestructura de estado-solido de los distintos componentes de la capa activa y se relacionan dichas características con sus propiedades optoelectrónicas. A continuación, la disertación se centra en estudiar la composición de los dominios de polímero (donor) y aceptor en la morfología con separación de fases a escala nanométrica denominada heterounión volumétrica (HUV). Finalmente, el control preciso logrado sobre la microestructura de los componentes individuales y la elección astuta de los disolventes y aditivos de procesado, permite delinear el impacto de tales características en relación morfología-función del dispositivo de la celda solar. De esta manera, el trabajo mostrado en este documento amplía la percepción actual de la estructura en estado sólido de los polímeros de alto rendimiento y la relación entre la microestructura, la morfología, el procesamiento en solución y el transporte de cargas en los dispositivos más eficientes de la actualidad. Además, se establece que es necesario un conocimiento exhaustivo de las propiedades físicas inherentes de los materiales orgánicos y su microestructura en estado-solido, para poder desarrollar dispositivos óptimos y realizar una transición eficiente de la escala laboratorio hacia una escala industrial.Polyma

    Reduction of the Lattice Thermal Conductivity of Polymer Semiconductors by Molecular Doping

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    Here we show that molecular doping of polymer thermoelectrics increases the electrical conductivity while reducing the thermal conductivity. A high-throughput methodology based on annealing and doping gradients within individual films is employed to self-consistently analyze and correlate electrical and thermal characteristics for the equivalent of >100 samples. We focus on the benchmark material system poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT) doped with molecular acceptor 2,3,5,6-tetrafittoro-7,7,8,8-tetra-cyanoquinodimethane (F4TCNQ). The thermal conductivity of neat PBTTT films is dominated by the degree of crystallinity, with thermal percolation observed for annealing temperatures >170 degrees C. Upon doping the samples with a relatively low amount of F4TCNQ (anion content <1 mol %), the thermal conductivity exhibits a two-fold reduction without compromising the crystalline quality, which resembles the effect of alloy scattering observed in several inorganic systems. The analysis of the relation between thermal and electrical conductivities shows that thermal transport is dominated by a doping-induced reduced lattice contribution.We acknowledge financial support from the Spanish Ministry of Science and Innovation through projects PGC2018-095411-B-I00 and MAT2017-90024-P (TANGENTS)-EI/FEDER, UE projects; the Generalitat de Catalunya through grants 2017SGR488 and AGAUR 2018 PROD 00191; and from the European Research Council (ERC) under grant agreement no. 648901. O.Z.-A. acknowledges CONACYT-SENER for his Ph.D. scholarship (no. 472571). J.M. thanks MCIU for the Ramo ' n y Cajal contract and grant PGC2018-094620-A-I00. We thank Dr. Agusti ' n Mihi for the access to and support with the FTIR equipment. We acknowledge the technical and human support provided by SGIker of UPV/EHU and European funding (ERDF and ESF). We thank Andre ' s Gom ' ez Rodrig ' uez from the Scanning Probe Microscopy Laboratory (ICMAB-CSIC) for a set of AFM measurements. We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI)

    Reduction of the Lattice Thermal Conductivity of Polymer Semiconductors by Molecular Doping

    Get PDF
    Here we show that molecular doping of polymer thermoelectrics increases the electrical conductivity while reducing the thermal conductivity. A high-throughput methodology based on annealing and doping gradients within individual films is employed to self-consistently analyze and correlate electrical and thermal characteristics for the equivalent of >100 samples. We focus on the benchmark material system poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT) doped with molecular acceptor 2,3,5,6-tetrafittoro-7,7,8,8-tetra-cyanoquinodimethane (F4TCNQ). The thermal conductivity of neat PBTTT films is dominated by the degree of crystallinity, with thermal percolation observed for annealing temperatures >170 degrees C. Upon doping the samples with a relatively low amount of F4TCNQ (anion content <1 mol %), the thermal conductivity exhibits a two-fold reduction without compromising the crystalline quality, which resembles the effect of alloy scattering observed in several inorganic systems. The analysis of the relation between thermal and electrical conductivities shows that thermal transport is dominated by a doping-induced reduced lattice contribution.We acknowledge financial support from the Spanish Ministry of Science and Innovation through projects PGC2018-095411-B-I00 and MAT2017-90024-P (TANGENTS)-EI/FEDER, UE projects; the Generalitat de Catalunya through grants 2017SGR488 and AGAUR 2018 PROD 00191; and from the European Research Council (ERC) under grant agreement no. 648901. O.Z.-A. acknowledges CONACYT-SENER for his Ph.D. scholarship (no. 472571). J.M. thanks MCIU for the Ramo ' n y Cajal contract and grant PGC2018-094620-A-I00. We thank Dr. Agusti ' n Mihi for the access to and support with the FTIR equipment. We acknowledge the technical and human support provided by SGIker of UPV/EHU and European funding (ERDF and ESF). We thank Andre ' s Gom ' ez Rodrig ' uez from the Scanning Probe Microscopy Laboratory (ICMAB-CSIC) for a set of AFM measurements. We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI)

    NEOTROPICAL CARNIVORES: a data set on carnivore distribution in the Neotropics

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    Mammalian carnivores are considered a key group in maintaining ecological health and can indicate potential ecological integrity in landscapes where they occur. Carnivores also hold high conservation value and their habitat requirements can guide management and conservation plans. The order Carnivora has 84 species from 8 families in the Neotropical region: Canidae; Felidae; Mephitidae; Mustelidae; Otariidae; Phocidae; Procyonidae; and Ursidae. Herein, we include published and unpublished data on native terrestrial Neotropical carnivores (Canidae; Felidae; Mephitidae; Mustelidae; Procyonidae; and Ursidae). NEOTROPICAL CARNIVORES is a publicly available data set that includes 99,605 data entries from 35,511 unique georeferenced coordinates. Detection/non-detection and quantitative data were obtained from 1818 to 2018 by researchers, governmental agencies, non-governmental organizations, and private consultants. Data were collected using several methods including camera trapping, museum collections, roadkill, line transect, and opportunistic records. Literature (peer-reviewed and grey literature) from Portuguese, Spanish and English were incorporated in this compilation. Most of the data set consists of detection data entries (n = 79,343; 79.7%) but also includes non-detection data (n = 20,262; 20.3%). Of those, 43.3% also include count data (n = 43,151). The information available in NEOTROPICAL CARNIVORES will contribute to macroecological, ecological, and conservation questions in multiple spatio-temporal perspectives. As carnivores play key roles in trophic interactions, a better understanding of their distribution and habitat requirements are essential to establish conservation management plans and safeguard the future ecological health of Neotropical ecosystems. Our data paper, combined with other large-scale data sets, has great potential to clarify species distribution and related ecological processes within the Neotropics. There are no copyright restrictions and no restriction for using data from this data paper, as long as the data paper is cited as the source of the information used. We also request that users inform us of how they intend to use the data
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