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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Coping with colorectal cancer and the creation of a colostomy in the Thai context

Rattanajarana, Sahattaya, n/a January 2005 (has links)
The number of patients who suffer from colorectal cancer in Thailand has increased during the last three decades as a result of the change to a Westem-style diet. Due to many patients presenting at a late stage and the location of tumours in the rectum, patients have a higher probability of needing a colostomy. This study explores the experiences, coping strategies and the factors that influence coping strategies over a sixmonth period in a group of Thai colorectal cancer patients who have a colostomy. The conceptual framework used in this study was based on the Moos and Schaefer conceptual model of the stress and coping process. A case study methodology was employed to collect both quantitative and qualitative data from eleven participants at three points in time: within one month after the operation to create a colostomy, three months and six months after the operation. Data were collected from structured interviews, which followed the Coping Responses Inventory (CRI), the Ostomy Adjustment Scale (OAS), the Personal Resources Questionnaire 2000 (PRQ 2000), the Life Orientation Test-Revised (LOT-R), and the Functional Assessment Cancer Therapy- Colon (FACT-C). These data provided information on the participants' levels of coping strategies, adjustment to a colostomy, social support, optimism and quality of life. Indepth interviews with open-ended questions provided a deeper understanding of the participants' experiences in relation to their colostomy. Findings from quantitative data showed statistically significant changes in the participants' quality of life over time, particularly in their physical and functional wellbeing. An examination of the coping focus used (approach and avoidance) indicated that participants utilised both approach and avoidance coping at the same time, although approach coping was more common. Changes in the most frequently and the least frequently used coping subtypes at six months after the operation were observed. Correlation tests showed various relationships between the levels of quality of life domains and coping subtypes as time passed. Multidimensional scaling procedures uncovered a consistent pattern of coping which involved 'problem solving' and 'seeking guidance and support'. Six major qualitative themes emerged through content analysis of the in-depth interview data. The themes described how participants' psychological and emotional concerns changed over time; the steady improvements in physical health after the operation; the difficulties of adjusting to life with a stoma; facing up to the reality of the new circumstances; the spiritual aspects of their lives; and the level of social support experienced. Religious beliefs such as the 'Law of Kanna', as well as a variety of religious rituals and other practices such as Buddhist chanting and "making merit" played important roles in coping. The findings from the quantitative and qualitative data were used in a complementary and confirmatory manner to provide a richer understanding of the participants' experiences as they coped with this life changing event. The findings of the study are significant as they provide important indicators for improvements in nursing service, particularly the development of nursing procedures to enhance the psychological aspects of care. In addition, they offer important indicators for improvement of the nursing curriculum and directions for further research in Thai culture and the health care system.
12

THE PRESIDENTIAL SELECTION PROCESS IN UNIVERSITIES

Steiner, John Frederick, 1945- January 1973 (has links)
No description available.
13

Fabricação e caracterização elétrica de filmes nanoestruturados de derivados do politiofeno / Fabrication and electrical characterization of nanostructured films of polythiophene derivatives

Roncaselli, Lucas Kaique Martins [UNESP] 19 February 2016 (has links)
Submitted by Lucas Kaique Martins Roncaselli (lucaskaiique@hotmail.com) on 2016-03-31T19:01:49Z No. of bitstreams: 1 dissertação - Fabricação e caracterização elétrica de filmes nanoestruturados de derivados do politiofeno.pdf: 2213057 bytes, checksum: 090f4d69287d8df3078f3e9849957e37 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-04-05T13:52:15Z (GMT) No. of bitstreams: 1 roncaselli_lkm_me_prud.pdf: 2213057 bytes, checksum: 090f4d69287d8df3078f3e9849957e37 (MD5) / Made available in DSpace on 2016-04-05T13:52:15Z (GMT). No. of bitstreams: 1 roncaselli_lkm_me_prud.pdf: 2213057 bytes, checksum: 090f4d69287d8df3078f3e9849957e37 (MD5) Previous issue date: 2016-02-19 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho foram utilizados derivados alquilados do politiofeno (P3ATs), sendo eles regioirregulares (RI) e regiorregulares (RR), diferenciados pela organização molecular. Esses materiais apresentam diferentes características quando fabricados usando técnicas diferentes como, a Langmuir-Blodgett (LB) e a Langmuir-Schaeffer (LS). O objetivo fica em fabricar filmes mistos com ambas as técnicas LB e LS, sendo os derivados misturados com ácido esteárico (Stearic Acid, SA), afim de verificar os diagramas de energia de acordo com a organização e condutividade de cada politiofeno. Foram depositados filmes de LB e LS de poli(3-butiltiofeno) (P3BT), poli(3-hexiltiofeno) (P3HT), poli(3-octiltiofeno) (P3OT) e de poli(3-dodectiltiofeno) (P3DDT). Os P3ATs poli(3-alquiltiofenos) foram depositados em ITO (Indium-Tin Oxide), e realizado para a caracterização desses materiais de espectroscopia UV-Visível, eletroquímicas e condutividade. Através dessas medidas foi possível estabelecer uma relação entre a organização, reversibilidade e condutividade desses materiais, possibilitando construir um diagrama de energia para esses derivados alquilados do politiofeno. / In this work we were used alkylated derivatives of polythiophene (P3ATs), and they regioirregulares (RI) andregiorregulares (RR), differentiated by molecular organization. These materials exhibit different characteristics when manufactured using different techniques such as the Langmuir-Blodgett (LB) and Langmuir-Schaeffer (LS). The objective is to manufacture mixed films with both LB and LS techniques, and derivatives mixed with stearic acid (Stearic Acid SA) in order to check the energy diagram according to the conductivity of each organization and polythiophene. LB films were deposited and LS poly(3-butylthiophene) (P3BT), poly(3-hexylthiophene) (P3HT), poly(3-octylthiophene) (P3OT) and poly(3-dodectiltiofeno) (P3DDT). The P3ATs poly(3-alquiltiofenos) were deposited on ITO (Indium-Tin Oxide), and held for characterizing these materials spectroscopy UV-Visible, electrochemical, and conductivity. Through these measures it was possible to establish a relationship between the organization, reversibility and conductivity of these materials, making it possible to build an energy diagram for these alkylated derivatives of polythiophene.
14

A Comparative Study of Rhoda Kellogg's Children's Artistic Development Research

Heather G Vickers (11812166) 20 December 2021 (has links)
<p>This investigation is a comparative study of the artistic development research of Rhoda Kellogg and the research of Helga Eng, Henry Schaefer-Simmern, and Viktor Lowenfeld. The intent of this investigation is to compare Kellogg’s children’s artistic development research to other theorists of the period to discover similarities and differences in her work, validating its significance. The criteria of the selection of the theorists limit the investigation to the research of children’s artistic development stage theories in the mid-twentieth century. The results of this investigation found that Kellogg’s children’s artistic development research consisted of far more categorizations of marks in the scribble and pre-schema stages than Eng, Schaefer-Simmern, and Lowenfeld’s research. The study also expands on the significance of Kellogg’s children’s artistic development research in the field of art education and the context in which Kellogg undertook her research. This investigation also brought attention to and documented Kellogg’s research more extensively than previous studies.</p>
15

DEVELOPMENT OF THERMALLY CONTROLLED LANGMUIR–SCHAEFER CONVERSION TECHNIQUES FOR SUB-10-NM HIERARCHICAL PATTERNING ACROSS MACROSCOPIC SURFACE AREAS

Tyler R Hayes (9754796) 14 December 2020 (has links)
<div> As hybrid 2D materials are incorporated into next-generation device designs, it becomes more and more pertinent that methods are being developed which can facilitate large-area structural control of noncovalent monolayers assembled at 2D material interfaces. Noncovalent functionalization is often leveraged to modulate the physical properties of the underlying 2D material without disrupting the extended electronic delocalization networks intrinsic to its basal plane. The bottom-up nanofabrication technique of self-assembly permits sub-10-nm chemical patterning with low operational costs and relatively simple experimental designs.</div><div> The Claridge Group is interested in leveraging the unique chemical orthogonality intrinsic to the cellular membrane as a means of creating sub-10-nm hydrophilic-hydrophobic striped patterns across 2D material interfaces for applications ranging from interfacial wetting to large-area molecular templates to guide heterogeneous nanoparticle assembly. Using Langmuir–Schaefer conversion, standing phases of polymerizable amphiphiles at the air-water interfaces of a Langmuir trough are converted (through rotation) to lying-down phases on 2D material substrates. Using room temperature substrates, transfer of amphiphiles to a lowered substrate results in small domains and incomplete surface coverage.</div><div> Recognizing that heating the substrate during the LS conversion process may lower the energy barriers to molecular reorientation, and promote better molecular domain assembly, we developed a thermally controlled heated transfer stage that can maintain the surface temperature of the substrate throughout the deposition process. We found that heating during transfer results in the assembly of domains with edge lengths routinely an order of magnitude larger than transfer using room temperature substrates that are more stable towards rigorous repeat washing cycles with both polar and nonpolar solvents.</div><div> To promote the effectiveness of the LS conversion technique beyond academic environments for the noncovalent functionalization 2D material substrates for next-generation device designs, we designed and built a thermally controlled rotary stage to address the longstanding scaling demerit of LS conversion. First, we report the development of a flexible HOPG substrate film that can wrap around the perimeter of the heated disk and can be continuously cycled through the Langmuir film. We found that thermally controlled rotary (TCR) LS conversion can achieve nearly complete surface coverage at the slowest translation speed tested (0.14 mm/s). TCR–LS facilitates the assembly of domains nearly 10,000 μm<sup>2</sup> which were subsequently used as molecular templates to guide the assembly of ultranarrow AuNWs from solution in a non-heated rotary transfer step. Together, these findings provide the foundation for the use of roll-to-roll protocols to leverage LS conversion for noncovalent functionalization of 2D materials. A true roll-to-roll thermally controlled LS conversion system may prove to be advantageous and a cost-efficient process in applications that require large areas of functional surface, or benefit from long-range ordering within the functional film.</div>
16

The effects of the Swedish moosemanagement

Kärrman, Victoria January 2019 (has links)
The purpose of this study was to examine the effects on the Swedish moose populationof a new moose management system introduced in 2012. To this end, the size of thepopulation had to be measured. The methodology used was an empirical version of theGordon–Schaefer bioeconomic model previously employed to estimate Sweden’s wildboar population. The Effort variable for the model was modified in that traffic accidentsrelative to traffic density served as a proxy for it. The study investigated years for whichdata was available, namely 2004–2017. Nineteen out of Sweden’s 21 Counties wereincluded in the study. The result produced extremely high population estimates,suggesting that the model could not be directly transferred from wild boar to moose.Nonetheless, although the study’s population estimates in absolute terms are unrealistic,their relative sizes indicate that moose populations were somewhat smaller in 2017 thanin 2012 – the latter year being when the new management system was introduced.However, the trend line shows that, over a longer period, the moose population hasincreased in Sweden, and 2017 may just be a temporary deviation from that trend. Itappears, therefore, that Sweden’s latest moose management system does not have thedesired effect on its moose population.
17

Surexploitation des ressources halieutiques : habitat, récifs artificiels et apprentissage / Overexploitation of marine resources : habitat, artificial reefs and learning

Udumyan, Narine 26 March 2012 (has links)
Cette thèse a pour thème central l'étude de deux problèmes soulevés dans les pêcheries modernes, la dégradation des habitats et le manque d'informations, qui comptent parmi les causes les importantes de la surexploitation des ressources halieutiques. Les deux premiers chapitres sont consacrés à l'examen du problème de la dégradation des habitats marins liée notamment aux activités de pêche destructrices. Le modèle de Gordon-Schaefer est prolongé afin de tenir compte de l'impact négatif de la pêche sur les habitats. Les conséquences pour la gestion sont analysées et l'importance de la prise en compte des habitats dans le développement des programmes de gestion des ressources halieutiques est mise en évidence. Le modèle élaboré est ensuite utilisé pour évaluer les bénéfices économiques des récifs artificiels, un outil de gestion auquel font de plus en plus appel les gestionnaires des pêcheries artisanales pour répondre à la dégradation des habitats. Enfin, dans le troisième chapitre, le rôle de l'information pour une pêche durable est examiné lorsque la ressource est en accès libre. Si, dans les deux premiers chapitres, il est supposé que les informations complètes sont disponibles pour l'élaboration des recommandations de gestion, dans la dernière étude, la décision concernant l'exploitation des ressources halieutiques est prise dans un contexte où aucune information sur la ressource n'est accessible. Cette décision est prise individuellement par chaque pêcheur qui opère dans la pêcherie. En développant un modèle multi-agents, nous montrons l'impact de l'apprentissage des pêcheurs sur la dynamique globale du système halieutique. / This thesis focuses on two main problems posed in contemporary fisheries: habitat degradation and lack of information. They count among the most important causes of the overexploitation of marine resources. The first two chapters aim at examining the habitat degradation that is linked to destructive fishing activities. The Gordon-Schaefer model is extended to take account of the negative impact of fishing on the habitats. The consequences for fisheries management are analyzed and the importance of taking into account habitats in the development of fisheries management programs is highlighted. Then the extended model is used to evaluate the economic benefits of artificial reefs, a management tool to which frequently resort the managers of small-scale fisheries to mitigate the effects of habitat degradation. Finally, in the third chapter the role of information for sustainable fisheries is examined under open access. If in the first two chapters it is assumed that there is complete information, in the last study this assumption is relaxed - no information on the resource is known. The decision concerning the exploitation of marine resources is made individually by each fisherman that operates in the fishery. By developing an agent-based model, we show the impact of individual learning on the global dynamics of the system.
18

Étude par microscopie à force atomique de la séparation de phase latérale de monocouches Langmuir-Schaefer de DPPC/DLPC

Sanchez, Jacqueline January 2003 (has links)
Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.
19

Tailoring Nanoscopic and Macroscopic Noncovalent Chemical Patterns on Layered Materials at Sub-10 nm Scales

Jae Jin Bang (5929496) 20 December 2018 (has links)
<p></p><p></p><p>The unprecedented properties of 2D materials such as graphene and MoS2 have been researched extensively [1,2] for a range of applications including nanoscale electronic and optoelectronic devices [3–6]. Their unique physical and electronic properties promise them as the next generation materials for electrodes and other functional units in nanostructured devices. However, successful incorporation of 2D materials into devices entails development of high resolution patterning techniques that are applicable to 2D materials. Patterning at the sub-10 nm scale is particularly of great interest as the next technology nodes require patterning of (semi)conductors and insulators at 7 nm and 5 nm scales for nanoelectronics. It will also benefit organic photovoltaic cells as phase segregation of p/n-type semiconducting polymers on 2D electrodes at length scales smaller than the typical exciton diffusion length (10 nm)</p> <p>is expected to improve the charge separation efficiency [7].</p><br><p></p><p></p><p>Characterizing locally modulated properties of non-ovalently functionalized 2D materials requires high-resolution imaging techniques capable of extracting measurements of various physical/chemical properties. One such method is scanning probe microscopy (SPM) [18–21]. In Chapter 1, we present a brief review of SPM modalities, some of which are used to characterize interfacial properties, such as conductivity and local contact potential differences that can be modulated by amphiphilic assemblies [17, 22]. Atomic force microscopy (AFM) is one of main techniques that we use to determine topography. All imaging in this work were performed in attractive AC mode [23,24] in order to minimize disruption to the self-assembly of the amphiphiles by the scanning tip.</p><br><p></p><p></p><p>One challenge of using SAMs for locally modulated functionalization is that the proximity to the nonpolar interface can modify the behavior of the functionalities present on the surface in conjunction with the steric hindrance of 2D molecular assemblies. For instance, ionizable functional groups, one of the strongest local modulators of surface chemistry, undergo substantial pKa shifts (in some cases, > 5 units) at nonpolar interfaces, limiting their ability to ionize. In order to apply molecular assembly to create 2D chemical patterns, we needed to design alternative structures that can avoid such penalties against the intrinsic properties of functionalities present in the assemblies. Among amphiphiles, we observed that the chiral centers of phospholipids have the potential of elevating the terminal functional group in the head from the surface for improved accessibility. We refer to this type of assembly as a ’sitting’ phase. Chapter 2 describes sitting phase assembly of phospholipids; the projection of the terminal functionality allows it to maintain solution phase-like behavior while the dual alkyl tails provide additional stabilizing interactions with the substrates. Given the diversity of phospholipid architecture [25], the sitting phase assembly suggests the possibility of greatly diversifying the orthogonality of the chemical patterns, allowing highly precise control over surface functionalities.</p><br><p></p><p></p><p>While a variety of methods including drop-casting [26–28] and microcontact printing [29] have been used previously by others for noncovalent assembly of materials on the surface, they mostly address patterning scale in the sub-μm range. Here, we utilize Langmuir-Schaefer(LS) transfer, which has been historically used to transfer standing phase multilayers [30], and lying-down domains of PCDA at < 100 nm scales in the interest of molecular electronics [14, 31–33], as our sample preparation technique. LS transfer is remarkable in that the transferred molecules relinquish their pre-existing interactions in the standing phase at air-water interface to undergo ∼ 90◦ rotation and assemble into the striped phase on a substrate. This introduces the possibility of modulating local transfer rate across the substrate by manipulating local environment of the molecules. Thus, LS transfer has the potential to offer spatial control over the noncovalent chemical functionalization of the 2D substrate, essential in device applications.</p><br><p></p><p></p><p>In Chapter 3 and 4, We make comparative studies of various experimental factors such as surface pressure, temperature and molecular interactions that affect the efficiency of LS conversion. Considering the energetics of the transfer process, we predicted that the rate of transfer from the air-water interface to the substrate should be the highest from the regions around defects, which would be the energetically</p> <p>least stable regions of the Langmuir film [34, 35]. In Langmuir films, two phases of lipid assemblies—liquid expanded (LE) and liquid condensed (LC)—often coexist at the low surface pressures (< 10 mN/m) used for sample preparation. Hence, we hypothesized that the microscale structural heterogeneity of Langmuir films could be translated into microscale patterns in the transferred film on HOPG. We compare the transfer rates between LE and LC phases and investigate the impacts of physical conditions during LS transfer such as temperature, packing density, dipping rate and contact time to conclude that local destabilization of Langmuir films leads to increased transfer efficiency. (Chapter 3)</p><p><br></p><p></p><p>As in the case of lipid membranes that reorganize routinely based on the structure of the constituent molecules [36–38], the structure of Langmuir films is strongly dependent on the molecular structures of the constituent molecules [39–43]. Accordingly, we expected the molecular structures/interactions to provide additional control over the LS transfer process. In Chapter 4, we compare domain morphologies and the average coverages between three single chain amphiphiles and two phospholipids, each</p><p></p><p> </p><p>of which contain hydrogen bonding motifs of varying strengths. We show that by influencing the adsorption and diffusion rates, molecular architecture indeed influences LS conversion efficiency and subsequent assembly on the substrate. The presence of strong lateral interactions limits transfer and diffusion, forming vacancies in the transferred films with smaller domain sizes while weaker intermolecular interactions enabled high transfer efficiencies.</p><p></p><p><br></p><p></p>
20

Fabricação e caracterização de células solares baseadas em polímeros orgânicos low-bandgap nanoestruturados / Fabrication and characterization of organic solar cells based on nanostructured low-bandgap polymers

Silva, Edilene Assunção da 05 July 2018 (has links)
Submitted by EDILENE ASSUNÇÃO DA SILVA (edileneass@gmail.com) on 2018-10-15T12:58:45Z No. of bitstreams: 1 Thesis final corrected version_Silva.pdf: 5038032 bytes, checksum: 096e39873786dd29f13d8faedd460bb8 (MD5) / Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2018-10-15T17:17:09Z (GMT) No. of bitstreams: 1 silva_ea_dr_bauru.pdf: 5038032 bytes, checksum: 096e39873786dd29f13d8faedd460bb8 (MD5) / Made available in DSpace on 2018-10-15T17:17:09Z (GMT). No. of bitstreams: 1 silva_ea_dr_bauru.pdf: 5038032 bytes, checksum: 096e39873786dd29f13d8faedd460bb8 (MD5) Previous issue date: 2018-07-05 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Les cellules solaires polymériques attirent un grand intérêt dans ce domaine de recherche, en raison du faible coût, du procédé de fabrication de grandes surfaces, des matériaux de manutention légers et de la possibilité de leur fabrication par diverses techniques. Pour une bonne efficacité des dispositifs photovoltaïques, la couche active doit contenir une bonne absorption de la lumière du soleil. En termes de bandgap,cela signifie que plus le bandgap est petit, plus le flux de photons absorbés est grand. Une manière d'accomplir ceci avec les matériaux polymères est la synthèse d'un copolymère alterné dans lequel le bandgap optique est diminué, ce que l'on appelle des polymères low-bandgap. L'organisation structurelle de la couche active joue un rôle important dans la performance des dispositifs, y compris les dispositifs photovoltaïques, et la technique Langmuir-Schaefer (LS) permet de fabriquer des films nanostructurés avec contrôle de l'épaisseur, qui peuvent servir de base pour construire de meilleurs dispositifs. Dans ce contexte, l'objectif de ce travail était de synthétiser des polymères low-bandgap et ensuite de fabriquer et caractériser des films LS de ces polymères et leurs mélanges avec un dérivé de fullerène, le PCBM, pour leur application en tant que couche active de cellules solaires. Les films LS des polymères et leurs mélanges avec PCBM ont été fabriqués et des mesures de caractérisation ont été effectuées. Ces films ont été caractérisés par des mesures électriques (courant vs tension, spectroscopie d'impédance et voltampérométrie cyclique), morphologiques (microscopie à force atomique) et optiques (UV-visible, diffusion Raman et transmission infrarouge). Par les films de Langmuir et les mesures morphologiques, il a été possible d'observer les caractéristiques spécifiques concernant la conformation de chaque polymère sous forme de film. Des mesures optiques confirment l'absorption aux longueurs d'onde élevées attendues pour ces polymères. Dans les mesures électriques, les résultats ont montré des conductivités différentes pour les mêmes matériaux lorsque les types d'électrodes ont été changés. Les dispositifs photovoltaïques des films LS fabriqués n'ont pas atteint de bonnes valeurs d'efficicacité. Les films spincoating de ces polymères testés en tant que couche active des dispositifs, sous atmosphère contrôlée, ont montré un’efficacité allant jusqu'à 0,6%. / Células solares poliméricas atraem grande interesse nessa área de pesquisa, devido ao baixo custo, processo de fabricação de grandes áreas, materiais de manuseio leves e a possibilidade de sua fabricação por diversas técnicas. Para uma boa eficiência dos dispositivos fotovoltaicos, a camada ativa deve conter uma boa absorção da luz solar. Em termos de bandgap, isto quer dizer que quanto menor o bandgap maior o fluxo de fótons absorvidos. Uma maneira de realizar isto com os materiais poliméricos é a síntese de um polímero no qual o bandgap óptico tem a capacidade de aumentar a captura da luz solar, os chamados polímeros low-bandgap. A organização estrutural da camada ativa possui um papel importante na performance de dispositivos, inclusive dos fotovoltaicos, e a técnica Langmuir-Schaefer (LS) proporciona a capacidade de fabricar filmes nanoestruturados e com controle de espessura, podendo servir de base para construção de melhores dispositivos. Dentro deste contexto, o objetivo deste trabalho foi sintetizar polímeros low-bandgap e, posteriormente fabricar e caracterizar filmes LS destes polímeros e de suas blendas com um derivado de fulereno, o PCBM, para a aplicação dos mesmos como camada ativa de células solares. Foram fabricados filmes LS dos polímeros e de suas misturas com PCBM e realizadas medidas de caracterização. Estes filmes foram caracterizados por meio de medidas elétricas (corrente vs. Tensão, espectroscopia de impedância e voltametria cíclica), morfológica (microscopia de força atômica) e óptica (Ultravioleta-Visível, Espalhamento Raman e transmissão no infravermelho). Com os filmes de Langmuir e as medidas morfológicas foi possível observar as características específicas de como é a conformação de cada polímero na forma de filme. As medidas ópticas confirmam a absorção em altos comprimentos de onda esperados para estes polímeros. Nas medidas elétricas os resultados mostraram diferentes condutividades para os mesmos materiais quando mudado os tipos de eletrodos. Os dispositivos fotovoltaicos dos filmes LS fabricados não alcançaram bons valores de eficiência. Filmes spin-coating destes polímeros testados como camada ativa dos dispositivos, em atmosfera controlada, revelaram eficiência de até 0.6%. / Polymeric solar cells attract great interest in this area of research due to the potential low cost, large area fabrication process, lightweight physical feature and the possibility of fabricating these cells by several techniques. To achieve good efficiency in the photovoltaic devices the active layer must have an efficient absorption of sunlight. In terms of bandgap, this means that the smaller the bandgap the greater the flux of photons absorbed. One way to accomplish this, with the polymeric materials, is the synthesis of a polymer in which the optical bandgap has the ability to increase the capture of sunlight, the so-called low-bandgap polymers. The structural organization of the active layer plays an important role in the performance of devices, including in photovoltaic devices, and the Langmuir-Schaefer (LS) technique provides the ability to manufacture nanostructured films with thickness control, which can serve as a basis for building better devices. In this context, the aim of this work was to synthesize low-bandgap polymers for later manufacturing and characterization of LS films of these polymers and their blends with a fullerene derivative, PCBM, and test them as active layer of solar cells. LS films of such polymers and their blends with PCBM were made and characterization measurements were performed. These films were characterized by electrical (current vs. voltage, impedance spectroscopy and cyclic voltammetry), morphology (atomic force microscopy) and optical (ultraviolet-visible, Raman scattering and infrared) measurements. Through the Langmuir films and the morphological measurements, it was possible to observe the specific characteristics of how it is the conformation of each polymer in film form. Optical measurements confirmed the absorption at high wavelengths expected for these polymers. In the electrical measurements, the results showed different conductivities for the same materials when the types of electrodes were changed. The photovoltaic devices manufactured from LS technique have not reached good efficiency values. When spin-coated active layers were tested as OPV devices in a controlled atmosphere the efficiency achieved up to 0.6% / CAPES DS / CNPq SWE 205489/2014-1

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