Syftet var att undersöka betydelsen av utseende vid val av socialsekreterare (som representerades av fotografier). Hälften av en undersökningsgrupp med 60 klienter (eller f.d.) valde att välja socialsekreterare i stället för att bli tilldelad och personbedömningar gjordes på grundval av enbart foton. / Person judgements of social workers were made by clients only on the basis of photos. / Examensuppsats handledd av Bo Edvardsson

The main purpose of this essay is investigating to which extent individuals withcompetence in film and photography can identify digitally processed material. Thestudy uses a questionnaire to create a statistical picture of the result. The participantsin the survey are part of a selected demographic consisting of current students atDalarna University (within film production) as well as graduated students. Throughthe survey, these individuals are divided into different groups based on theircompetence in film and photography. The survey consists of two tests whereparticipants view, compare and assess a material that has been filmed with a diffusingcamera filter (Tiffen pro mist) and a material that has been processed digitally torecreate the same effect. What diffusion is and how it affects the image will also bepresented in the text. A total of 36 individuals participated in the study. The results donot show a definitive answer for any of the competence groups. This indicates that inthe case of diffusion there does not necessarily exist any especially strong advantagesto using a genuine camera filter. What can be established however, is that a higher levelof competence in film and photography is synonymous with a general, overallknowledge of camera filters and digital processing. / Det huvudsakliga syftet med denna uppsatts är att undersöka huruvida individer medkompetens inom film och foto kan identifiera digitalt bearbetat material. Studienkommer med hjälp av en enkät skapa en statistiks bild av ett stickprov. Deltagarna ienkäten är en utvald demografi bestående av nuvarande studenter vid HögskolanDalarna (inom filmproduktion) och även examinerade studenter. Dessa individer delasgenom enkäten upp i olika grupper baserad på deras kompetens inom film och foto.Själva enkäten består av två tester där deltagare bes skilja på ett material som är filmatmed ett diffuserande kamerafilter (Tiffen pro mist) och ett material som behandlatsdigitalt för att återskapa samma effekt. Vad diffusion är och hur det påverkar bildenkommer också utvecklas i texten. Totalt har 36 individer deltagit i studien, resultatetvisar inte något definitivt svar i frågeställningen för någon av kompetensgrupperna.Detta tyder på att det i fallet för diffusion inte nödvändigtvis finns en särskilt starkfördel med att använda ett analogt kamerafilter. Det som dock kan fastställas är att enhögre kompetens inom film och foto innebär en övergripande generell kunskap omkamerafilter och den digitala processen.

Rephotography has been a popular research topic in the photography field for a long time. The purpose of rephotography itself is to repeatedly take photographs of the same scene at a different time. As a result, the sequence of rephotographs with the reference, often historical, the picture provides a compelling visualization of the evolution of the subject or capture its changes in time. However, the act of rephotography is difficult for the rephotographers as they have to cope with the ambiguous motions in six degrees of freedom and with the changes of the subject itself or its surrounding environment.        This thesis aims to create a mobile application that would help its users to capture a rephotograph more accurately and allow them to share the scenes amongst other users. The designed application uses available on-device sensors to navigate the user to the location and guide the user during the rephotography process to capture a precise rephotograph. Furthermore, the application contains user interface elements designed explicitly for rephotography. Moreover, the work describes topics about user interface design, iOS application development, and designing and deploying backend API for the mobile application.

[pt] O presente trabalho tem por objetivo analisar a degradação do fármaco Clonazepam (CZP), um dos remédios controlados mais vendidos no mundo e um possível contaminante emergente das águas residuais e de superfície. Foi realizada a degradação do composto a partir da fotólise UVC do peróxido de hidrogênio, das reações de Fenton fotoassistida (Foto-Fenton) por lâmpadas UVA, UVC, e por radiação solar, assim como pelo Sistema H2O2/Óxidos de Ferro, para efeito de comparação. Todas as análises foram conduzidas por cromatografia líquida de alta eficiência (CLAE) com detector UV. Os resultados alcançaram conversões acima de 85 por cento em boa parte dos experimentos e indicaram a cinética, em sua maioria, com ordem aparente próxima a 2 e k igual 0,95 mg. L-1. min-1 no Foto-Fenton UVC e k igual 0,02 mg.L-1.min-1 no Sistema H2O2/Óxidos de Ferro. Além disso, foi feita a análise de toxicidade utilizando sementes de alface para o H2O2/Óxidos de Fe, a fotólise UVC e para o Foto-Fenton com lâmpada UVC, com valores de inibição de crescimento de até 44 por cento. / [en] The present work aims at analyzing the degradation of the drug Clonazepam (CZP), one of the best-selling controlled drugs in the world and a possible emerging contaminant of surface and wastewater. Compound degradation was performed by UVC photolysis of hydrogen peroxide, photo-assisted Fenton reactions (Photo-Fenton) by UVA, UVC lamps, and solar radiation, as well as by the H2O2/Iron Oxides System for comparison purposes. All analyses were conducted by high performance liquid chromatography (HPLC) with UV detector. The results reached conversions above 85 percent in most of the experiments and indicated the kinetics, mostly, with apparent order close to 2 and k equal 0.95 mg. L-1. min-1 in Photo-Fenton UVC and k equal 0.02 mg.L-1.min-1 in H2O2/Iron Oxides. In addition, toxicity analysis was carried out using lettuce seeds for H2O2/Iron Oxides, UVC photolysis and UVC lamp Photo-Fenton, with growth inhibition values of up to 44 percent.

[ES] El agua se convirtió en uno de los recursos más escasos de la Tierra. Por eso es necesario desarrollar nuevas tecnologías para el tratamiento adecuado de las aguas residuales urbanas (UWW), permitiendo su reutilización. Múltiples tecnologías han demostrado ser efectivas cuando se aplican individualmente, pero a menudo no se aplican ni se integran en el tratamiento convencional de UWW, lo que resulta en la pérdida de posibles efectos sinérgicos. Por estas razones, la investigación sobre la combinación e integración de estas tecnologías es de suma importancia. Cuando se aplican de esta manera, también se conocen como Tecnologías Integradas Avanzadas. Hecho un trabajo de investigación sobre el rendimiento de una planta piloto de nanofiltración (NF) a escala piloto para UWW, seguido de la aplicación de métodos de tratamiento (químico). Los Procesos de Oxidación Avanzada (AOP), como el proceso (solar) foto-Fenton (SPF), aprovechan el ciclo catalítico del hierro (Fe2+ y Fe3+), la luz UV-vis, junto con un agente oxidante, como el peróxido de hidrógeno (H2O2), produciendo radicales hidroxilo altamente reactivos. Este proceso de foto-Fenton (solar) se aplica a un pH 3, para evitar la precipitación del hierro, o a un pH más alto mediante agentes quelantes, como el ácido etilendiamino-N, N'-disuccínico (EDDS). Los microcontaminantes (MC) usados fueron cafeína, imidacloprid, tiacloprid, carbamazepina y diclofenaco. La preconcentración es un paso esencial antes de aplicar AOP como tratamiento terciario de los efluentes de las plantas de tratamiento de aguas residuales urbanas (EDAR), ya que reduce significativamente el volumen a tratar y, por lo tanto, los costos económicos. El tratamiento de la corriente de concentrado de la NF mediante el proceso de SPF demostró ser efectivo para la eliminación de los MC mencionados anteriormente cuando se utilizó H2O2 como agente de oxidación. Por lo tanto, a una mayor degradación de los MC se adhiere una toxicidad directamente proporcionalmente menor. Las investigaciones incluyen la valorización de los efluentes EDAR mediante la recuperación de amonio, con la eliminación combinada de MC mediante NF y diferentes AOPs, con el fin de producir corrientes de permeado para la fertilización e irrigación directa de cultivos, también conocida como 'fertirrigación'. Esto incluye el proceso de SPF, pero también se combina con procesos de electrooxidación (EO). El SPF fue más efectivo al tratar las corrientes de concentrado de NF a pH circunneutro, con una concentración de MC inferior a 1 mg/L. Las corrientes de concentrado de NF altamente salinas son ideales para ser tratadas mediante procesos de EO, por sus alta conductividad, con un consumo eléctrico significativamente menor con la asistencia solar. La eficiencia de retención de MC por NF y la toxicidad después de los tratamientos con AOP también se evaluaron mediante la determinación de la fitotoxicidad del permeado. Los resultados mostraron que los permeados utilizados para los cultivos (Sorghum saccharatum, Sinapis alba, Lepidium sativum) redujeron la germinación de las semillas. Contrariamente, se observó que la irrigación con los permeados producidos generalmente promovió el desarrollo de las raíces, mientras que el desarrollo de los brotes prosperó solo cuando se usaron permeados que tenían factores de concentración inferiores al factor de concentración 2. Los estudios mostraron que los permeados deberían diluirse primero en un mínimo del 50%, para ser adecuados para la irrigación directa. El trabajo también incluyó la evaluación de una membrana de ultrafiltración (UF) cerámica foto catalítica TiO2-ZrO2 previamente desarrollada. La disminución del flujo puede revertirse cuando se irradia la membrana UF cerámica con luz en un simulador solar. La retención microbiológica de la membrana UF fue determinada utilizando una cepa bacteriana Gram negativa, Pseudomonas aeruginosa y fue capaz de retener consistentemente hasta un orden de magnitud de 1 x 104 UFC/ml. / [CA] L'aigua es va convertir en un dels productes bàsics més escassos de la Terra. Per tant, cal desenvolupar noves tecnologies, com el tractament adequat de les aigües residuals urbanes (UWW) per a la seva reutilització. Múltiples tecnologies avançades es demostren efectives quan s'apliquen únicament. Aquestes tecnologies sovint no s'apliquen ni s'integren en el tractament UWW convencional. Com a resultat, es perd possibles efectes sinèrgics. Per aquests motius, la investigació sobre la combinació i integració d'aquestes noves tecnologies és de la màxima importància. Quan s'apliquen així, aquestes tecnologies combinades també es coneixen i s'indiquen com a Tecnologies Integrades Avançades. Es va realitzar un treball de recerca sobre el rendiment d'una planta de nanofiltració (NF) a escala pilot per a la preconcentració d'UWW, seguida de l'aplicació de mètodes de tractament (químics), per tal de tractar els corrents de concentrat i permeat produïts. Els processos d'oxidació avançats (AOP), com el procés foto-Fenton (solar) (SPF), fan servir el cicle catalític del ferro (Fe2+ i Fe3+), la llum UV-vis, juntament amb un agent oxidant, com el peròxid d'hidrogen (H2O2), produint radicals hidroxil altament reactius i no selectius. Aquest procés SPF s'aplica a pH3, per tal d'evitar la precipitació del ferro, o a pH circumneutral aplicant agents quelants com l'àcid etilendiamina-N, N¿-disuccinic (EDDS). La preconcentració és un pas essencial abans d'aplicar els AOP com a tractament terciari d'efluents d'EDAR, ja que redueix significativament el volum a tractar i, per tant, els costos globals. El tractament del corrent de concentrat del NF mitjançant el procés SPF va demostrar ser eficaç per a l'eliminació de diferents microcontaminants (MC) quan s'utilitzava H2O2 com a agent d'oxidació. Per al qual una degradació de MC més alta s'adhereix a una toxicitat menor directament proporcional. Els seleccionats (MC) van ser cafeïna, imidacloprid, tiacloprid, carbamazepina i diclofenac. Els treballs de recerca posteriors van tractar la valorització dels efluents d'EDAR mitjançant la recuperació d'amoni, amb l'eliminació combinada de MC per NF i diferents AOP avançats, per tal de produir corrents permeats per a la fertilització directa dels cultius i el reg, també anomenats "fertirrigació". Inclou SPF, però també combinat amb processos d'electrooxidació (EO). El SPF va ser més eficaç quan es tractaven corrents de concentrat de NF a pH circumneutral, a una concentració de MC inferior a 1 mg/L, per obtenir una degradació ràpida de MC. Els corrents concentrats de concentrat NF altament salins són ideals per ser tractats mitjançant processos EO, alhora que posseeixen una alta conductivitat, i un menor consum elèctric significatiu per assistència solar. També es va avaluar l'eficiència de retenció de MC per NF i la toxicitat després dels tractaments amb AOP determinant la fitotoxicitat del permeat. Els resultats van mostrar que els permeats podrien reduir la germinació de llavors si s'utilitzaven per a cultius (Sorghum saccharatum, Sinapis alba, Lepidium sativum). Al contrari d'això, es va demostrar que el reg amb els permeats produïts afavoria generalment el desenvolupament de les arrels, mentre que el desenvolupament dels brots només va prosperar quan s'utilitzaven permeats que tenien factors de concentració inferiors a 2. Els estudis de toxicitat van mostrar que els corrents de permeat s'havien de diluir primer amb un mínim del 50% aigua dolça. El treball de recerca realitzat també va incloure l'avaluació d'una membrana d'ultrafiltració ceràmica (UF) fotocatalítica TiO2-ZrO2 desenvolupada prèviament. La disminució del flux es pot revertir quan la membrana fotocatalítica UF va ser irradiada per llum en un simulador solar. La retenció microbiològica de la membrana UF es va determinar mitjançant el desplegament d'una soca bacteriana gramnegativa, Pseudomonas aeruginosa, ser capaç de retenir constantment fins a un ordre de magnitud d'1 x 104 CFU/ml. / [EN] Water turned to be one of Earths scarcest commodities. Therefore, novel technologies need to be developed, as appropriate treatment of produced urban wastewaters (UWWs) for its reuse as irrigation waters or aquifer recharge. Multiple advanced technologies are proven effective when applied solely. These technologies are often not applied or integrated into conventional UWW treatment. Resulting in missing out on potential synergetic effects. For these reasons that research into the combining and integration of these novel technologies is of the utmost importance. When thus applied, these combined technologies are also known and indicated as Advanced Integrated Technologies. Research work was conducted on the performance of a pilot scale nanofiltration (NF) plant for UWW pre-concentration, followed by the application of (chemical) treatment methods, in order to treat the produced concentrate and permeate streams. Advanced Oxidation Processes (AOPs), such as the (solar) photo-Fenton process make use of the catalytic cycle of iron (Fe2+ and Fe3+), UV-vis light, along with an oxidizing agent, such as hydrogen peroxide (H2O2), producing highly reactive and non-selective hydroxyl radicals (¿OH). This (solar) photo-Fenton process is applied at acidic pH3, in order to prevent iron precipitation, or at circumneutral pH by applying chelating agents such as Ethylenediamine-N, N¿-disuccinic acid (EDDS). Preconcentration is an essential step before applying AOPs as tertiary treatment of UWWTP effluents, as it significantly lowers the to be treated volume, and therefore the overall costs. Treating the concentrate stream from the NF by the solar photo-Fenton process showed to be effective for the removal of different microcontaminants (MCs) when H2O2 was used as an oxidation agent. Opposite to that, the application of persulfate and its derived radicals showed lower degradation of the selected MC. For which a higher MC degradation is adhered to a directly proportional lower toxicity. Selected (MCs) were caffeine, imidacloprid, thiacloprid, carbamazepine, and diclofenac. Further research work covered UWWTP effluent valorization by the recovery of ammonium, with combined MC elimination by NF and different advanced AOPs, in order to produce permeate streams for direct crop fertilization and irrigation, also called 'fertigation'. Including solar photo-Fenton, but also combined with electrooxidation (EO) processes. Solar photo-Fenton was most effective when treating NF concentrate streams at circumneutral pH, at MC concentration lower than 1 mg/L, to obtain rapid MC degradation. High saline and concentrated NF concentrate streams are ideal to be treated by EO processes, while possessing high conductivity. Obtaining significant lower electric consumption by solar assistance. MC retention efficiency by NF and toxicity after AOP treatments was also assessed by determining the permeate phytotoxicity. Results showed that permeates could lower seed germination if they would be used for crops (Sorghum saccharatum, Sinapis alba and Lepidium sativum). Contrary to that, it was showed that irrigation with the produced permeates generally promoted root development, while shoot development only thrived when using permeates which had concentration factors lower than 2. Toxicity studies showed that permeate streams should first be diluted with a minimum of 50% fresh water, in order to be suitable for direct crop irrigation in agriculture. Conducted research work also included the assessment of a priorly developed (collaboration with an PhD within MSCA AQUAlity) photocatalytic TiO2-ZrO2 ceramic ultrafiltration (UF) membrane. Flux decline can be reversed when the photocatalytic UF membrane was irradiated by light in a solar simulator. Microbiological retention of the UF membrane was determined by deploying a Gram-negative bacterial strain, Pseudomonas aeruginosa (P. Aeruginosa). It was able to consistently retain till an order of magnitude of 1x10^4 CFU/ml. / This PhD Thesis has received funding from the European Union’s Horizon 2020 research and innovation program, the AQUAlity project, under the Marie SkłodowskaCurie grant agreement No 765860. Performing research work at CIEMAT – Plataforma Solar de Almería. / Deemter, RD. (2024). Application of Advanced Integrated Technologies (Membrane and Photo-Oxidation Processes) for the Removal of CECs contained in Urban Wastewater [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/203099

The purpose with this paper is to study the function of computer, in the teaching of One-to-One.   To get information and answers to the purpose and issues, a number of educators were interviewed. Research and literature in the field have been studied.   The questions discussed are: what strategies do teachers use and develop in their teaching and do they feel that their students reach higher results in One-to-One-teaching. The interviewed teachers have all good or very good computer experience but lack adequate teaching  methods in One-to-One.   The computer's function in the One-to-One is to be an educational tool. It replaces DVD, MP-3, pencil and paper and several other things. The study shows that communication between students and educators increases and leads to higher results. The increased communication will also ease a formative evaluation. God result in teaching requires well planned and structured lessons. You can see some shortcomings in pupils source criticism. The respondents request for a relevant education in One-to-One.   As One-to-One is a relatively new field of research, the research needs further and deeper studies. Research in the area didactics connected to an One-to-One project is an important area. It would be interesting to study how teachers use the computer from a didactic point of view.   Another field that needs to be studied is the question whether ”weak” students benefit from the One-to-One concept or not.   Do the students affects the socioeconomic background. A future research area would be: Are there differences in results based on the students' socioeconomic background, initially as well as by time, with the introduction of One-to-One. / Syftet med detta arbete är att studera vilken funktion datorn får i undervisningen inom En-till-En.   För att få information och svar till syfte och frågeställningar har ett antal pedagoger intervjuats. Forskning och litteratur inom området har studerats.   Frågeställningarna är vilka strategier som lärare använder och utvecklar i sin undervisning samt om pedagogerna upplever att deras elever når ett högre resultat inom En-till-En-undervisningen. De intervjuade pedagogerna har samtliga goda eller mycket goda datorkunskaper men saknar relevant utbildning inom En-till-En.   Datorns funktion inom En-till-En blir ett pedagogiskt redskap. Den ersätter DVD, mp-3, papper och penna och flera andra redskap. Studien visar att kommunikationen mellan elev och pedagog ökar och leder till att elever når högre resultat. Den ökade kommunikationen underlättar även en formativ bedömning. För att undervisningen skall vara givande krävs att lektionerna är grundligt planerade och har en tydlig struktur. En annan pedagogisk vinst är att även brister i elevernas källkritik upptäcks. Relevant fortbildning inom En-till-En efterfrågas.   Då En-till-En är ett relativt nytt forskningsfält pekar studien på ytterligare och djupare studier. Forskning inom området didaktik kopplat till En-till-En är ett angeläget område. Här skulle det vara intressant att se hur pedagoger använder datorn i sin didaktik.   Ett annat fält som vore angeläget att studera vidare är om svaga elever lyckas i lägre grad vid En-till-En i jämförelse med traditionell undervisning.   Ett framtida forskningsfält skulle kunna vara: Finns det skillnader i resultat som grundar sig i elevernas socioekonomiska bakgrund, såväl initialt som efter tid, vid införandet av En-till-En.

In cooperation with projects from colleagues in Berlin and powered by the British Museum in London, we present an ongoing project whose aim is to produce a digital edition of the Rosetta Stone (the “Decree of Memphis”). The project has two main goals: 1) textual alignment of the Hieroglyphic, Demotic and Greek versions of the Rosetta Stone; 2) morphosyntactic annotation of the three versions of the inscription. As first results, we present: 1) examples of alignment of the Hieroglyphic version of the text with translations into modern languages (through the Alpheios alignment editor; 2) the complete morphosyntactic annotation of the Greek text of the Rosetta Stone (through the Arethusa treebanking editor).

A comprehensive understanding of physiological role of proteins requires knowledge of their three-dimensional structure, dynamics and protein-protein interactions. Chemical cross-linking in combination with mass spectrometry represents an alternative approach to standard methods for protein structure elucidation (X-ray crystalography, NMR spectroscopy) and enables characterization of interaction interface within protein complexes in their native states. The presented thesis is mainly focused on novel cross-linking methodology based on the in vivo incorporation of methionine analog with photo-reactive functional group (photo-Met) into the sequence of studied protein (so called protein photo-nanoprobe). Interaction between two molecules of 14-3-3zeta protein was used as a model to test and optimize the protein photo-nanoprobe production. The findings confirmed usefulness of this approach for mapping the protein-protein interactions. The photo-initiated cross-linking was used to detect the heterooligomeric membrane structures of cytochromes P450 2B4 and b5 and the molar ratio of cytochromes within individual complexes was assessed. The chemical cross-linking in combination with mass spectrometry was employed to characterize the interaction of their catalytic domains and two mutual orientations of...

Esta tese teve por objetivo, desde seu início, investigar as propriedades elétricas de um dispositivo ITO/PEDOT:PSS/P3HT:PCBM/Ca/Al, o qual é uma estrutura bem conhecida de célula solar orgânica do tipo de heterojunção de volume (bulk-heterojunction – BHJ), e com isso dar uma contribuição à melhora de seu desempenho. Porém, o primeiro passo foi introduzir no Grupo de Polímeros Bernhard Gross, um método eficaz de produzir células solares do tipo BHJ com boa eficiência e reprodutibilidade. Esse primeiro desafio foi alcançado com sucesso. A eficiência (η) de um dispositivo fotovoltaico de multicamadas depende de muitos fatores. Dentre eles, uma boa superposição entre o espectro solar e a curva de absorção da camada absorvedora, uma excelente conversão da energia luminosa em portadores de carga, um eficiente processo de condução e uma perda mínima por recombinação e armadilhamento de portadores. Além disso, a compatibilidade eletrônica entre as interfaces tem um papel fundamental na definição na tensão de circuito aberto (VOC), no valor da corrente de curto-circuito (JSC), e no fator de preenchimento (FF). Baseado nesses efeitos, realizamos uma série de medidas experimentais, que auxiliado por um modelo teórico proporcionaram um estudo detalhado da evolução em função da temperatura da mobilidade dos portadores (μ) e de seu tempo de vida (τ). Os principais experimentos nessa tese foram realizados em diferentes temperaturas (entre 100 e 340 K). Foram eles: medidas de fotocorrente - Jph(V), a técnica de foto-CELIV, e medidas de transiente de fotovoltagem (TPV). Em paralelo, desenvolvemos o modelo teórico para a descrição analítica de Jph(V) que assumiu contatos não-injetores e que o livre caminho médio (w = μτF) de elétrons e buracos eram iguais (F é o campo elétrico). Nos ajustes teórico/experimental usamos a probabilidade de dissociação dos estados de transferência de carga (P) e o produto μτ como parâmetros de ajuste. A condição na qual o livre caminho médio é maior que a espessura da amostra (w >> L) reproduz a corrente de saturação reversa, Jsat = qGPLG é a taxa de geração dos éxcitons. Para w << L, a fotocorrente varia linearmente com o livre caminho médio, ou seja, J(F) = qGPμτF. A comparação entre os resultados experimentais e os teóricos permitiram, além da obtenção da evolução das grandezas μ e τ com a temperatura, estabelecer uma relação efetiva entre os parâmetros da célula (η, JSC, e FF) e as propriedades elétricas da camada ativa P3HT:PCBM. As medidas termo-mecânicas (DMA) forneceram informações adicionais sobre mudanças estruturais da camada ativa, as quais foram correlacionadas com variações dos parâmetros da célula e com fatores de perda. Finalmente, medidas de tempo-de-voo (TOF) e de CELIV foram realizadas para estudos mais detalhados sobre mecanismos de transporte ao longo da camada ativa, a efeitos de injeção pelos eletrodos, e para o entendimento de efeitos de degradação pela ação do oxigênio. / This thesis aims to investigate electrical characteristics of an ITO/PEDOT:PSS/P3HT:PCBM/Ca/Al device, which is a well-known structure of a bulk-heterojunction (BHJ) organic solar cell, and to contribute to improve its performance. However, the first step was to introduce in the Group of Polymer Bernhard Gross an effective method for producing BHJ solar cells, manufacturing thus devices exhibiting excellent performance and reproducibility. This thesis aims to investigate electrical characteristics of an ITO/PEDOT:PSS/P3HT:PCBM/Ca/Al device, which is a well-known structure of a bulk-heterojunction (BHJ) organic solar cell, and to contribute to improve its performance. However, the first step was to introduce in the Group of Polymer Bernhard Gross an effective method for producing BHJ solar cells, manufacturing thus devices exhibiting excellent performance and reproducibility. This goal was successfully achieved. The good efficiency (η) of a multilayer photovoltaic cell depends on many factors, including good overlap between the solar spectrum and the light absorbing layer, an excellent conversion of the absorbed light energy in pairs of electronic carriers, efficient charge transport and the minimum losses by recombination or by the action of deep traps for the carriers. Furthermore, the compatibility between electronic interfaces plays a crucial role in defining the open-circuit voltage (VOC) and the value of short-circuit current (JSC), and on the fill factor (FF). Anchored on these effects, we carried out a series of experiments, aided by a theoretical modeling, which provided a detailed study of the temperature evolution of fundamental electric quantities such as carrier mobility (μ) and its lifetime (τ). These studies were performed with the help of different experiments: photocurrent in function of the applied voltage  Jph(V), Photo-CELIV technique, and Transient Photovoltage (TPV) measurements, which were carried out at several temperatures in the 100 to 340 K range. In parallel, we developed an analytical model for Jph(V) that assumed non-injecting contacts and equal mean-free-paths for electrons and holes. The theoretical/experimental entities used as fitting parameters were the charge-transfer-state dissociation probability (P) and the μτ product. The condition in which the mean-free-path (w = μτF) is higher the sample thickness (L), the model reproduces the experimental reverse saturation current, Jsat = qGPL, which is coincident with the experimental value. F is the internal electric field and G is the generation rate of excitons by the absorbed light. When w << L, J(F) = qGPμτF, which is also coincident with experimental behavior. The confrontation between the experimental results and the theoretical model provided, in addition to the study of the evolution of μ and τ with temperature, to establish a more effective relationship between the parameters (η, JSC, e FF) of the cell and the electrical properties of the P3HT:PCBM active layer. Thermomechanical analysis (DMA) provided additional information of structural changes of active layer, which can be correlated with change in the loss factor and in the cell parameters. Finally, Time-of-Flight (TOF) and CELIV techniques were used in the more accurate study of charge transport along the active layers, effects of injection by the electrodes, and the degradation effect caused by oxygen.

Polímeros contendo grupos azo-benzênicos têm sido estudados devido a sua capacidade para óptica não linear, formação de superfícies de relevo e de birrefringência fotoinduzida. O fator que possibilita essas aplicações é a propriedade de fotoisomerização reversível trans-cis-trans do grupo azo que produz a sua reorientação molecular. Neste trabalho foram produzidos filmes casting do poliuretano MDI-DR19 derivado de azo-benzeno. Estudou-se o crescimento e decaimento da birrefringência para diferentes valores de potência da luz de excitação da fotoisomerização. Os resultados experimentais do crescimento e decaimento foram analisados usando duas exponenciais e eles mostraram que o polímero MDI-DR19 apresenta boas características para utilização em armazenamento óptico pois cerca de 65% da birrefringência induzida no material permanece por longos intervalos de tempo. Ilustramos o processo de armazenamento de informação gravando uma imagem de birrefringência num filme de MDI-DR19. Foram também produzidas grades de relevo em filmes de MDI-DR19 utilizando franjas de interferência produzidas com luz de polarização P e S. Essas grades apresentaram alta uniformidade e características compatíveis com as mostradas na literatura. / Polymers containing azobenzenic groups have been studied due to their applications on non-linear optics, surface relief gratings (SRG) and photoinduced anisotropy for optical storage. The reversal photoisomerization trans-cis-trans property of the azo group induces a molecular reorientation. In this work, cast films of na azobenzene derivative, the polyurethane MDI-DR19, were studied. The build-up and decay of the birefringence were studied as a function of the photoisomerization exciting light power. The data of the build-up and decay of the birefringence were fitted with a bi-exponential function, which shows the stability of the MDI-DR19 for application in optical storage, since 65% of the induced birefringence remains after a long time. The optical storage is illustrated by recording a birefringence image in a film of MDI-DR19. It was also performed a SRG over films of MDI-DR19 applying an interference finger pattern with a P and S polarized light. The light induced gratings shows good uniformity and characteristics compatible with those presented in the literature.