Two-dimensional drift-diffusion simulation of organic solar cells

The aim of this master's thesis is to develop a two-dimensional drift-di usion model, which describes charge transport in organic solar cells. The main bene t of a two-dimensional model compared to a one-dimensional one is the inclusion of the nanoscale morphology of the active layer of a bulk heterojunction solar cell. The developed model was used to study recombination dynamics at the donor-acceptor interface. In some cases, it was possible to determine e ective parameters, which reproduce the results of the two-dimensional model in the one-dimensional case. A summary of the theory of charge transport in semiconductors was presented and discussed in the context of organic materials. Additionally, the normalization and discretization procedures required to nd a numerical solution to the charge transport problem were outlined. The charge transport problem was solved by implementing an iterative scheme called successive over-relaxation. The obtained solution is given as position-dependent electric potential, free charge carrier concentrations and current densities in the active layer. An interfacial layer, separating the pure phases, was introduced in order to describe charge dynamics occurring at the interface between the donor and acceptor. For simplicity, an e ective generation of free charge carriers in the interfacial layer was implemented. The pure phases simply act as transport layers for the photogenerated charges. Langevin recombination was assumed in the two-dimensional model and an analysis of the apparent recombination rate in the one-dimensional case is presented. The recombination rate in a two-dimensional model is seen to e ectively look like reduced Langevin recombination at open circuit. Replicating the J-U curves obtained in the two-dimensional model is, however, not possible by introducing a constant reduction factor in the Langevin recombination rate. The impact of an acceptor domain in the pure donor phase was investigated. Two cases were considered, one where the acceptor domain is isolated and another where it is connected to the bulk of the acceptor. A comparison to the case where no isolated domains exist was done in order to quantify the observed reduction in the photocurrent. The results show that all charges generated at the isolated domain are lost to recombination, but the domain does not have a major impact on charge transport. Trap-assisted recombination at interfacial trap states was investigated, as well as the surface dipole caused by the trapped charges. A theoretical expression for the ideality factor n_id as a function of generation was derived and shown to agree with simulation data. When the theoretical expression was fitted to simulation data, no interface dipole was observed.

Traités publics de la royale maison de Savoie avec les puissances étrangères, depuis la paix de Cateau-Cambrésis jusqu'à nos jours. Tome 6 / publiés par ordre du roi et présentés à S. M. par le comte Solar de La Marguerite, premier secrétaire d'Etat pour les affaires étrangères, etc.

[Traité (recueil). Royaume de Sardaigne (français)]

Traités publics de la royale maison de Savoie avec les puissances étrangères, depuis la paix de Cateau-Cambrésis jusqu'à nos jours. Tome 3 / publiés par ordre du roi et présentés à S. M. par le comte Solar de La Marguerite, premier secrétaire d'Etat pour les affaires étrangères, etc.

[Traité (recueil). Royaume de Sardaigne (français)]

Traités publics de la royale maison de Savoie avec les puissances étrangères, depuis la paix de Cateau-Cambrésis jusqu'à nos jours. Tome 4 / publiés par ordre du roi et présentés à S. M. par le comte Solar de La Marguerite, premier secrétaire d'Etat pour les affaires étrangères, etc.

[Traité (recueil). Royaume de Sardaigne (français)]

Traités publics de la royale maison de Savoie avec les puissances étrangères, depuis la paix de Cateau-Cambrésis jusqu'à nos jours. Tome 2 / publiés par ordre du roi et présentés à S. M. par le comte Solar de La Marguerite, premier secrétaire d'Etat pour les affaires étrangères, etc.

[Traité (recueil). Royaume de Sardaigne (français)]

Traités publics de la royale maison de Savoie avec les puissances étrangères, depuis la paix de Cateau-Cambrésis jusqu'à nos jours. Tome 5 / publiés par ordre du roi et présentés à S. M. par le comte Solar de La Marguerite, premier secrétaire d'Etat pour les affaires étrangères, etc.

[Traité (recueil). Royaume de Sardaigne (français)]

Passive Solar Building Design Using Genetic Programming

Passive solar building design is the process of designing a building while considering sunlight exposure for receiving heat in winter and rejecting heat in summer. The main goal of a passive solar building design is to remove or reduce the need of mechanical and electrical systems for cooling and heating, and therefore saving energy costs and reducing environmental impact. This research will use evolutionary computation to design passive solar buildings. Evolutionary design is used in many research projects to build 3D models for structures automatically. In this research, we use a mixture of split grammar and string-rewriting for generating new 3D structures. To evaluate energy costs, the EnergyPlus system is used. This is a comprehensive building energy simulation system, which will be used alongside the genetic programming system. In addition, genetic programming will also consider other design and geometry characteristics of the building as search objectives, for example, window placement, building shape, size, and complexity. In passive solar designs, reducing energy that is needed for cooling and heating are two objectives of interest. Experiments show that smaller buildings with no windows and skylights are the most energy efficient models. Window heat gain is another objective used to encourage models to have windows. In addition, window and volume based objectives are tried. To examine the impact of environment on designs, experiments are run on five different geographic locations. Also, both single floor models and multi-floor models are examined in this research. According to the experiments, solutions from the experiments were consistent with respect to materials, sizes, and appearance, and satisfied problem constraints in all instances.

Análisis del cambio de proceso de unión de placa con orificios y tubo en un intercambiador de calor

Tesis (Maestría en Ciencias de la Ingeniería Mecánica con Especialidad en Térmica y Fluidos) UANL

Estudio de la transferencia de calor en lecho fijo (primera aproximación, caso unidimensional) César Alberto Núñez López

Tesis (Maestría en Ciencias en Ingeniería Mecánica, con especalidad en Ingeniería de Materiales) U.A.N.L.

Modelo matemático lineal aproximado en transferencia de calor (caso unidimensional) [por] Mauricio Acencio Santillán Marroquín

Tesis (Maestría en Ciencias de Ingeniería Mecánica, con especialidad en Materiales) - U.A.N.L, 1992

Modelación de la transferencia de calor en una aleación Al-Si tipo 319 [por] Jesús Talamantes Silva

Tesis (Maestría en Ciencias de la Ingeniería Mecánica con Especialidad en Materiales) U.A.N.L.

Impacto de la transferencia de calor por radiación en las propiedades del vidrio calizo durante el formado de contenedores vítreos por Raquel Mendoza Reséndez

Tesis (Maestría en Ciencias con Especialidad en Ingeniería Cerámica) U.A.N.L.

Diseño y mantenimiento de equipos de transferencia de calor por Benito Sergio Garza Espinosa.

Tesis (Maestro en Ciencias de la Ingeniería Mecánica con Especialidad en Térmica y Fluidos) U.A.N.L.

Efecto de la presión del vapor sobre el coeficiente de transferencia de calor por convección libre

Tesis (Maestro en Ciencias de la Ingeniería Mecánica con Especialidad en Térmica y Fluidos) UANL, 1998.

Determinación experimental de coeficientes de transferencia de calor para convección libre y forzada

Tesis (Maestro en Ciencias de la Ingeniería Mecánica con Especialidad en Térmica y Fluidos) UANL, 1998.