CAPES / A preocupação em alcançar o desenvolvimento sustentável está cada vez mais presente na construção civil, sendo este o setor que mais contribui com os maiores níveis de emissões de gases de efeito estufa, devido ao grande consumo de energia e recursos naturais. Adicionalmente, os edifícios despendem de uma grande quantidade energética para aplicações cotidianas e em muitos países, as fontes são provenientes de fontes não-renováveis, causando dependência de combustíveis fósseis e consequentemente elevação nos índices de emissões de CO2. Portanto, as “transições de sustentabilidade” mediante a aplicação de novos sistemas de energia renováveis, os quais apresentam emissões reduzidas, como por exemplo, a energia solar fotovoltaica, viabilizam essa mudança. Essa fonte de energia está cada vez mais presente na matriz energética mundial, seja pela aplicação de usinas fotovoltaicas de grande porte ou por meio de usinas geradoras de mini e microgeração incorporada às edificações, atuando como geração distribuída inserida no meio urbano. Neste sentido, este trabalho tem por objetivo contribuir com redução da demanda, com a eficiência energética e a quantificação das emissões de CO2 equivalente que podem ser evitadas com a energia gerada, por meio da utilização da energia fotovoltaica na UTFPR – câmpus Curitiba. A metodologia consiste na análise dos parâmetros de irradiação local horizontal e inclinada coletados por meio do portal do INMET, do Atlas Brasileiro de Energia Solar e do Piranômetro da UTFPR para aplicação do software Radiasol. Por sua vez, efetuouse o estudo do perfil de cargas da instituição, a fim de identificar os momentos de maiores consumo e demanda por energia elétrica, através da seleção de dias típicos elencados no decorrer do ano. A análise das coberturas possibilitou o levantamento de áreas disponíveis e análise de sombreamento, e através dos dados gerados pelos Sistemas Fotovoltaicos Conectados à Rede existentes foram elaborados cenários, objetivando a contribuição energética do câmpus. Por fim, foram calculados os níveis de penetração energéticos, bem como o fator efetivo de capacidade de carga, quantificando o aumento da capacidade disponível da rede elétrica atribuída à geração fotovoltaica e as respectivas emissões evitadas. Os resultados obtidos mostram que a UTFPR - câmpus Curitiba apresenta um vasto potencial para a geração de energia fotovoltaica, sendo que a instituição poderia alocar um sistema com potência instalada total de 3,25 MW, e gerar um total anual de energia de 4,37 GWh. Com relação ao nível de penetração energético total calculado, obteve-se 489,97%, o que significa a ocorrência de injeção do excedente de energia fotogerada no sistema elétrico. Pode-se concluir que além da possibilidade de redução de custos com energia elétrica, existiria uma redução significativa nas emissões de GEE’s referentes ao cálculo de CO2 podendo evitar a emissão de 284,43 tCO2 ao ano. / The concern of achieving sustainable development is increasingly present in civil construction, which is the sector that shows the highest levels of greenhouse gas emissions due to its high consumption of energy and natural resources. Buildings use a large amount of energy in their day-to-day use, and in many countries this energy comes from non-renewable sources, causing dependence on fossil fuels and consequently increasing CO2 emissions."Sustainable transitions" make change possible through the application of new renewable energy systems, which present reduced emissions, e.g. solar photovoltaic energy. This energy source is increasingly present in the global energy matrix, both in large-scale photovoltaic plants and smalland micro-generation incorporated into buildings, acting as distributed generation in urban environments. The objective of this thesis is to contribute to a reduction in demand, with energy efficiency and to the quantification of equivalent CO2 emissions that could be avoided with energy generated through the use of photovoltaic energy at UTFPR’s Curitiba campus. The methodology consists of the analysis of horizontal and inclined local irradiation parameters collected through the INMET portal, the Brazilian Solar Energy Atlas and the piranometer at UTFPR, and in the application of the software Radiasol. The study of the load profile of the institution was carried out in order to identify periods of greater consumption and demand for electric energy, through the selection of typical days during the year. The analysis of the coverages allowed the survey of available areas and a shading analysis. Through the data generated by the existing grid-connected photovoltaic system, scenarios were elaborated to model the energy contribution of the three campus. Finally, the energy penetration levels and the effectiveness factor of the load capacity were calculated quantifying the increase of the available capacity of the electricity grid, attributed to the photovoltaic generation, as well as the respective emissions avoided. The results show that the Curitiba campus of UTFPR have a vast potential for the generation of photovoltaic energy, and the institution could allocate a system with a total installed power of 3.25 MW, generating an annual total of 4.37 GWh of energy. The calculated total energy penetration level of 489.97% was obtained, which implies the injection of a surplus of photo-generated energy into the electric system. It can be concluded that besides the possibility of reducing electricity costs, there would be a significant reduction in GHG emissions calculated at 284.43 tCO2 per year.

Thesis (MPhil (Public Management and Planning))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The thesis examines whether a residential solar power system (comprising a solar photovoltaic [PV] system and a solar water heater [SWH]), a demand-side option, has a lower life-cycle cost than a coal-fired power plant, a supply-side option, or vice versa. It also investigates whether a million residential solar power systems could potentially replace a 4 800 MW coal-fired power plant in South Africa. The study also explores, should a million solar power systems be installed on residential units, what the total energy output, the equivalent in coal-fired generation capacity, and the comparative costs of the two power systems would be. The common belief is that solar PV technology is unviable for electricity production because it is too expensive compared to coal-based electricity. Statements such as these are made because the initial capital costs (procurement costs) are often used as the primary (and sometimes only) criterion for project, equipment or system selection based on a simple payback period. Due to life-cycle stages, often the real costs of the project or equipment are not reflected by the upfront capital costs. In this thesis, a methodology is developed to investigate the life-cycle cost effectiveness of a residential solar power system (comprising a 5 kW PV roof tile system and a 300 litre SWH) and a 4 800 MW coal-fired plant in order to choose the most cost effective alternative in terms of the project‟s functional unit (kWh). A 5 kW solar PV roof tile system and a 300 litre SWH system have been installed at Lynedoch Eco-village. The operational results from this experiment was used as a basis for developing a model for a million residential rooftops that will have a 5 kW PV roof tile system plus a 300 litre SWH system. The focus of the million rooftops model is operating costs over the lifetime of the solar power system, on the assumption that the capital costs will be financed from coal-fired generation capacity that will no longer be needed. The results of the study indicate that a residential solar power system is most cost effective over a 40-year life-cycle period in terms of the project‟s functional unit (kWh). The thesis also finds that a million residential solar power systems (comprising a 5 kW PV system and a 300 litre SWH) could potentially replace 40% of a 4 800 MW coal-fired generation capacity. In total, 2.3 million residential solar power systems are needed to replace a 4 800 MW coal-fired generation capacity. Emissions of 37 million tonnes of CO2 equivalent per year could be avoided if 2.3 million residential solar power systems were to be installed. However, the investment needed to install Lynedoch solar power systems (comprising a 5 kW PV roof tile system and a 300 litre SWH) on 2.3 million residential rooftops is fifteen times more than the investment needed to build a 4 800 MW coal-fired power plant. The investment needed to install 2.3 million Lomold residential solar power systems (comprising a 5 kW Lomold PV roof tile system and a 300 litre SWH) is six and half times more than the investment needed for a 4 800 MW coal-fired power plant. It was established during the study that if Lynedoch residential solar power systems were to be installed on the roofs of a million South African households, 152 308 jobs would be created in the manufacturing and installation supply chain. For the 2.3 million Lynedoch residential solar power systems needed to replace an entire 4 800 MW of coal-fired generation capacity, 340 690 jobs would be created in the manufacturing and installation supply chain. Installation of a million Lomold residential solar power systems would create 63 929 jobs in the supply chain. Installation of 2.3 million Lomold residential solar power systems would essentially create 147 298 jobs. / AFRIKAANSE OPSOMMING: Die tesis stel ondersoek in na die vraag of ʼn residensiële sonkragstelsel (bestaande uit ʼn fotovoltaïese (FV) stelsel en ʼn sonwaterverhitter [SWV]), ʼn vraagkant-opsie, ʼn laer lewensikluskoste as ʼn steenkoolkragsentrale, ʼn aanbodkant-opsie, het of omgekeerd. Daar word ook ondersoek of ʼn miljoen residensiële sonkragstelsels potensieel ʼn 4 800 MW-steenkoolkragsentrale in Suid-Afrika kan vervang. Verder word daar ondersoek, indien ʼn miljoen sonkragstelsels op residensiële eenhede aangebring word, wat die totale energie-uitset, die gelykstaande uitset van steenkool-opwekkingskapasiteit en die vergelykende koste van die twee kragstelsels sal wees. Die algemene oortuiging is dat sonkrag- FV tegnologie ongeskik is vir elektrisiteitsopwekking omdat dit te duur is in vergelyking met steenkoolgebaseerde elektrisiteit. Sodanige stellings word gemaak omdat die aanvanklike kapitaalkoste (aankoopkoste), gegrond op ʼn eenvoudige terugbetalingstydperk, dikwels as die primêre (en soms selfs die enigste) maatstaf tydens die keuse van ʼn projek, toerusting of stelsel dien. Die werklike kostes van ʼn projek of toerusting word egter dikwels nie in kapitaalkostes weerspieël nie, omdat hierdie maatstaf nie totale lewensikluskoste in ag neem nie. In hierdie tesis word ʼn metodologie ontwikkel om die lewensiklus-kostedoeltreffendheid van ʼn residensiële stelsel (bestaande uit ʼn 5 kW FV-dakteëlstelsel en ʼn 300 liter-SWV) en ʼn 4 800 MW-steenkoolkragsentrale te bereken sodat die kostedoeltreffendste opsie in terme van die projek se funksionele eenheid (kWh) gekies kan word. ʼn Residensiële sonkragstelsel bestaande uit ʼn 5 kW FV-dakteëlstelsel en ʼn 300 liter-SWV is in Lynedoch Eco-village geïnstalleer. Die operasionele resultate van die eksperiment is gebruik as grondslag vir die ontwikkeling van ʼn model vir die installering van ʼn 5 kW sonkrag-FV-dakteëlstelsel en ʼn 300 liter-SWV op ʼn miljoen residensiële dakke. Die fokus van die hierdie model is die operasionele koste oor die leeftyd van die sonkragstelsel, gegrond op die aanname dat die kapitaalkoste gefinansier sal word deur fondse wat nie meer vir die oprig van steenkoolkragsentrales benodig word nie. Die tesis se bevindinge dui daarop dat ʼn residensiële sonkragstelsel die kostedoeltreffendste is oor ʼn lewensiklustydperk van 40 jaar in terme van die projek se funksionele eenheid (kWh). Daar is ook gevind dat ʼn miljoen residensiële sonkragstelsels (bestaande uit ʼn 5 kW FV-dakteëlstelsel en ʼn 300 liter-SWV) potensieel 40% van ʼn 4 800 MW-steenkoolkragsentrale se kapasiteit kan vervang. Altesaam 2.3 miljoen residensiële sonkragstelsels is nodig om die kapasitiet van ʼn 4 800 MW-steenkoolkragsentrale ten volle te vervang. Gasvrystelling van 37 miljoen ton CO2-ekwivalent per jaar kan vermy word as 2.3 miljoen residensiële sonkragstelsels geïnstalleer word. Die belegging wat benodig word om Lynedoch-sonkragstelsels (bestaande uit ʼn 5 kW FV-dakteëlstelsel en ʼn 300 liter-SWV) op 2.3 miljoen residensiële dakke te installeer, is egter vyftien keer groter as die belegging wat benodig word om ʼn 4 800 MW-steenkoolkragsentrale te bou. Die belegging wat benodig word om Lomold- residensiële sonkragstelsels (bestaande uit ʼn 5 kW Lomold-FV-dakteëlstelsel en ʼn 300 liter-SWV) te installeer, is ses en ʼn half keer groter as die belegging wat nodig is om ʼn 4 800 MW-steenkoolkragsentrale op te rig. Die studie het bepaal dat as Lynedoch- residensiële sonkragstelsels op die dakke van ʼn miljoen Suid-Afrikaanse huishoudings geïnstalleer word, 152 308 werksgeleenthede in die vervaardigings- en installeringsaanbodketting geskep sal word. Met die 2.3 miljoen Lynedoch- residensiële sonkragstelsels wat benodig word om ʼn 4 800 MW-steenkoolkragsentrale te vervang, sal 340 690 werksgeleenthede in die vervaardigings- en installeringsaanbodketting geskep word. Die installering van ʼn miljoen Lomold- residensiële sonkragstelsels sal 63 929 werksgeleenthede in die voorsieningsketting skep, terwyl die installering van 2.3 miljoen Lomold- residensiële sonkragstelsels 147 298 werksgeleenthede sal skep. / Centre for Renewable and Sustainable Energy Studies

Thesis (MBA)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Many rural areas in Africa still lack adequate electricity supply. This has been identified as a major obstacle to development in many African nations. The high costs associated with providing electricity through national grid systems prevent many governments from delivering electricity to remote rural areas. The purpose of this study is to define a strategic architecture and business model that can be used to provide solar energy to Small, Medium and Micro Enterprises (SMMEs) in Africa. The desired outcome is a sustainable business model for solar energy provision that can be implemented in the African context. This study uses the strategic architecture framework developed by Ungerer, Pretorius and Herholdt (2011) to achieve this. Primary data was collected through interviews with industry experts and this was supplemented with a comprehensive review of current literature. An analysis of the PV market shows that solar PV has grown significantly over the past decade and the industry is already extremely competitive. The highest competitive pressures include substitute products, high buyer bargaining because of low product differentiation, and the threat of new entrants. The industry has a clearly defined value chain starting with the manufacturing of PV panels and other systems components, but goes as far as providing financing to customers. The profit potential in the industrial and commercial segments is highest and key competitors in this segment offer similar products and services. The customer analysis showed that small businesses vary considerably in the products and services they offer and that their energy needs also differ. Services that can be offered to these customers include energy efficiency assessments, system design, pre-project services, financing, system installation and system monitoring, operation and maintenance. The organisation that will implement the strategy is a company called Solshare. The organisation identified its vision and mission, and core values and defined the domain it will participate in. The commercial and industrial segments are regarded as the most appealing segments and the core product offering is energy efficiency assessments and solar installations. This will be offered through an innovative shared-solar model that also includes system financing, system monitoring and system optimisation, and will be implemented by carefully selected partners to minimise cost. Solshare’s objective is to develop a distinctive competence in financing and implementing shared-solar projects through strategic partnerships, while providing excellent customer service. It will employ is a focused low-cost strategy by providing solar energy to small businesses at the lowest cost possible, through a shared resource approach. Costs will be managed by focusing on a core set of activities and outsourcing non-core activities. The key value proposition is the development, installation and servicing of quality shared-solar solutions at the lowest cost. The cost drivers include the costs of solar system components procured from suppliers, the installation costs, salaries, marketing costs, system maintenance, and legal fees to draw up contracts and lease agreements. Income streams include energy assessments, fees charged for site selection and procurement, the installation of systems, and the monitoring and maintenance of installed systems. The capital mix consists of 30% equity and 70% debt and organisation aims to optimise resource velocity through completing new installations within a four month period and by employing a core team of professional sales and technical staff, while outsourcing non-core processes.

This thesis improves our understanding of the charge-transfer dynamics in organic materials employed in dye-sensitized and nanotube-thiophene solar cells. For the purpose of this work, a femtosecond transient absorption spectroscopy setup was built. Additionally, microsecond transient absorption spectroscopy was utilised to explore dynamics on a longer time-scale. In the first study, the dependence of dye regeneration and charge collection on the pore- filling fraction (PFF) in solid-state dye-sensitized solar cells (DSSCs) is investigated. It is shown that while complete hole transfer with PFFs as low as ~30% can be achieved, improvements beyond this PFF are assigned to a stepwise increase in the charge-collection efficiency in agreement with percolation theory. It is further predicted that the chargecollection efficiency saturates at a PFF of ~82%. The study is followed by an investigation of three novel hole-transporting materials for DSSCs with slightly varying HOMO levels to systematically explore the possibility of reducing the loss-in-potential and thus improving the device efficiency. It is shown that despite one new HTM showing a 100% hole-transfer yield, all devices based on the new HTMs performed worse than those incorporating spiro-OMeTAD. Furthermore, it is demonstrated that the design of the HTM has an additional impact on the electronic density of states present at the TiO₂ electrode surface, and hence influences not only hole- but also electron-transfer from the sensitizer. Finally, a study on a polymer-single-walled carbon nanotube (SWNT) molecular junction is presented. Results from femtosecond spectroscopic techniques show that the polymer poly(3-hexylthiophene) (P3HT) is able to transfer charges to the SWNT within 430 fs. Addition of excess P3HT polymer leads to long-lived free charges making these materials a viable option for solar cells.

Submitted by Maicon Juliano Schmidt (maicons) on 2015-07-13T18:32:37Z No. of bitstreams: 1 Miguel Francisco da Silveira.pdf: 1561110 bytes, checksum: dcb1486a17c6616e1fcf6803ce1272ec (MD5) / Made available in DSpace on 2015-07-13T18:32:37Z (GMT). No. of bitstreams: 1 Miguel Francisco da Silveira.pdf: 1561110 bytes, checksum: dcb1486a17c6616e1fcf6803ce1272ec (MD5) Previous issue date: 2013-01-31 / Milton Valente / UNISINOS - Universidade do Vale do Rio dos Sinos / Muito tem se falado sobre o uso de fontes alternativas de energia e do uso de pequenas fontes em geração distribuída (GD), especialmente com a nova legislação brasileira que agora considera esta possibilidade. O aproveitamento da energia solar vem crescendo ao longo dos últimos anos, tanto através de seu uso como fonte térmica, quanto através da geração fotovoltaica, baseado no baixo impacto ambiental desta fonte de energia. Este trabalho tem por objetivo estudar o impacto da geração distribuída no sistema de distribuição de energia elétrica pelo uso de geradores fotovoltaicos conectados diretamente à rede de distribuição. O estudo é realizado em regime permanente, sob o ponto de vista elétrico, em um alimentador específico, considerando curvas típicas propostas para dias ensolarados e encobertos. Para esta análise foi utilizada uma base de dados de um ano, com dados de irradiância e de temperatura do ar ambiente coletados na cidade de Porto Alegre - RS entre Julho de 2004 e Junho de 2005. Esta base de dados serviu para estabelecer as curvas típicas de geração de um dia ensolarado e de um dia encoberto, através de uma metodologia desenvolvida. Com o uso destas curvas típicas foi definido o padrão de geração fotovoltaica em um dia ensolarado e em um dia encoberto. Após a definição deste padrão de geração foi possível analisar o impacto em um alimentador específico, localizado na cidade de Viamão - RS. A análise do impacto na rede considerou a influência que a geração distribuída ocasiona nos níveis de tensão nos diferentes nós ao longo do alimentador. Foi considerada uma penetração de 20% de GD, em dois diferentes horários para um dia ensolarado e para um dia encoberto. A potência gerada foi normalizada em relação à potência consumida nos diferentes pontos do alimentador. Os impactos observados na rede de distribuição não foram relevantes, entretanto a geração fotovoltaica contribuiu levemente para a melhora em alguns níveis de tensão que estavam na faixa crítica, em alguns cenários analisados. / Alternative sources of energy and distributed generation (DG) are current subjects, especially in Brazil where the regulations had just changed and now the possibility of DG and compensation of energy can be considered. The use of solar energy has been increased along the last years, thus as a heat source or as photovoltaic (PV) generation, based mainly on the low environmental impact of this energy source. This essay aims to study the impact of distributed generation in the electrical energy distribution system caused by the use of photovoltaic generators connected straight to the distribution grid. The study is done in steady state condition, in a specific feeder, considering typical curves proposed for sunny and cloudy days. A data base of irradiance and temperature of air ambient of one year had been used for this analysis. The data had been collected in the city of Porto Alegre – RS – Brazil, from July 2004 to June 2005. This data base was used to establish the generation typical curves of sunny and cloudy days through a methodology developed. The photovoltaic generation standards for sunny and cloud days had been defined by the use of these typical curves. With these standards were possible to analysis the impact in a specific feeder, located in the city of Viamão – RS – Brazil. The analysis of the impact in the grid considered the influence of distributed generation could cause on voltage levels at different bars along the feeder. It had been considered a penetration of DG of 20%, in two different hourly times for each day, sunny and cloudy typical curves. The power generated had been normalized related to the power consumed in different points of the feeder. The impact observed in the distribution grid is not relevant. However, the distribution generation did contribute to slightly raise some voltage levels that are already among the critical zone, in some of the sets analysed.

Made available in DSpace on 2017-07-10T17:11:49Z (GMT). No. of bitstreams: 1 Romulo Bainy2.pdf: 2925977 bytes, checksum: f7adb8982457ac4631549de0def5054e (MD5) Previous issue date: 2015-03-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work evaluated the effect of the variation of some factors over the transient behavior of a feeder from a Distribution Power System where there are Distributed Generator (DG) connected. Two types of distributed generation were evaluated, which are photovoltaic and wind power. The chosen Distribution Power System has 32 nodes and was presented by (de Abreu, 2005) and (Salim, 2010). First of all, this feeder was characterized and the nodes were separated on four clusters, comply some electric characteristics from each one. Each cluster has a chosen node that represents the center of the group from the cluster, which resulted on four candidates nodes. Than, it was time to build the scenarios for simulation, they were made by two candidate node and fault node, which means that there are six possible scenarios. To chose the fault node, there is some premises: None of GD can generate on a islanded operation; It is not necessary that all scenarios has the same fault node; and, the more important one, the fault node must have fault current similar on all scenarios. The studied factors were: Loading of the feeder; Power factor of the loads; X/R relation of lines; GFV conexion; FSIG conexion. The simulation evaluated the influence of each factors. Among the five , only two showed influence in the transient behavior of the system: the connection ratio X/R and the FSIG conexion . The other three did not shown influence. Thus, the two factors correspond to valuable study object , and should be considered when evaluating the transient behavior at Distribution System with DG. / Este trabalho avaliou a influência de alguns fatores sobre o comportamento transitório de um alimentador de um sistema de distribuição com geradores distribuídos conectados. Dois tipos de geração distribuída foram avaliados, sendo eles a fotovoltaica e a eólica. O sistema elétrico de distribuição (SED) escolhido possui 32 nós e foi apresen-tado por (de Abreu, 2005) e em (Salim, 2010). Primeiramente este alimentador foi caracterizado e os nós separados em 4 clusters, conforme algumas características elétricas de cada um. Para cada cluster um nó foi escolhido como representante das centroide, ou seja, mais similar com a identidade do grupo. O trabalho seguiu com a concepção dos cenários de simulação, estes compostos pela junção destes quatro nós em duplas, além do nó de falta, o que se traduz em seis possíveis cenários. A escolha do nó para inserção de um curto-circuito trifásico respeitou três premissas: não causar ilhamento em nenhum dos geradores distribuídos; não é necessário que o nó de falta de todos os cenários seja igual; e, a premissa mais importante, que ele deve gerar uma corrente de falta com valor similar em todos os cenários.Os fatores avaliados foram: Carregamento do Alimentador; Fator de Potência das Cargas; Relação X/R das linhas de distribuição; Conexão do GFV; Conexão do FSIG.Cada um dos fatores sofreu uma quantidade específica de variações para que seu efeito sobre o comportamento transitório fosse investigado. Dentre esses cinco, apenas dois se mostraram capazes de influenciar no comportamento transitório do sistema: a relação X/R e a conexão do FSIG. Os outros três não demonstraram grande influência, sendo sempre imperceptível o efeito de sua variação. Dessa forma, a variação dos dois fatores corresponde a valioso objeto de estudo, sendo necessário considerá-los quando se deseja avaliar o comportamento transitório de um Sistema de Distribuição com geradores distribuídos.

The solar industry has grown considerably in the last few years. This larger scale has introduced more problems as well as possibilities. One of those possibilities is analyzing the data coming from the sites that are now being monitored, and using the information to answer a variety of questions. We have four questions which are of prime importance identified in this thesis: 1. Can data from customers be trusted? 2. Can we use data from existing sites to determine which sites need the most improvement? 3. Can we implement a location-based algorithm to reduce the amount of false positives for performance, or other alarms? 4. Can we improve upon the current predicted power algorithm? We find that not only can we answer these questions definitively, but the improvements found are of significant value. Each of these items represents an important question that either directly or indirectly translates into increased revenue and engineering improvements for the solar industry as a whole.

The overall goal of this research is to improve fundamental understanding of the hydrogen passivation of defects in low-cost silicon and the fabrication of high-efficiency solar cells on thin crystalline silicon through low-cost technology development. A novel method was developed to estimate the flux of hydrogen, released from amorphous silicon nitride film, into the silicon. Rapid-firing-induced higher flux of hydrogen was found to be important for higher defect passivation. This was followed by the fabrication of solar cell efficiencies of ~ 17% on low-cost, planar cast multicrystalline silicon. Solar cell efficiencies and lifetime enhancement in the top, middle, and bottom regions of cast multicrystalline silicon ingots were explained on the basis of impurities and defects generally found in those regions. In an attempt to further reduce the cost, high-efficiency solar cells were fabricated on thin crystalline silicon wafers with full area aluminum-back surface field. In spite of loss in efficiency, wafer thinning reduced the module cost. Device modeling was performed to establish a roadmap towards high-efficiency thin cells and back surface recombination velocity and back surface reflectance were identified as critical parameters for high-efficiency thin cells. Screen-printed solar cells on float zone material, with efficiencies > 19% on 300 μm and > 18% on 140 μm were fabricated using a novel low-cost fabrication sequence that involved dielectric rear passivation along with local contacts and back surface field.

For organic electronic device applications materials are needed which display good charge carrier mobility, good processability, and stability towards oxygen and moisture. Alkynylated N-Heteroacenes fulfill many of these requirements. Substitution with alkyne groups as well as the introduction of the pyrazine subunit both inhibits oxidative degradation at sensitive position in the molecules. Additionally the trialkylsilylethynyl group aides in directing the packing motif as well as vastly increases the solubility over unsubstituted analogues. A requisite precursor in the synthesis of alkynylated N-heteroacenes is alkynylated acenothiadiazoles. These thiadiazoles display interesting photophysical properties and can be functionalized to produce a wide range of properties in closely related materials. The acenothiadiazoles themselves have potential applications as an N-type semiconductor. Optical gaps and calculated HOMO-LUMO gaps show that these molecules, when compared to known N-type materials, should be easily injected with electrons. Additionally the crystal packing of these compounds shows favorable π-orbital overlap which should provide excellent charge carrier mobilities.

The Master's Thesis research focuses on analyzing the possibilities of using Direct Current distribution systems to distribute power to end users. Considering the shift in load types in the past few decades and also a growing demand of distributed generation, DC distribution can potentially offer higher efficiencies and cost savings to utilities. The incorporation of DC distribution offers the opportunity to eliminate multiple conversion stages for devices which are powered using DC electricity. The integration of power sources such as photovoltaics and fuel cells, which produce DC power, offer further incentives to consider the use of DC systems. Using DC systems can help eliminate the conversion losses associated with rectifiers and inverters which would be part of the infrastructure if AC distribution was used. In the literature, the study of DC distribution has been limited to customized systems. The objective of this research is to analyze DC distribution when applied to systems based on standard IEEE test feeder systems. The IEEE 13 node test feeder and the IEEE 37 node test feeder will be used as the basis for the analysis. Issues such as associated costs, protection and integration of appliances will also be addressed.