Monica Julieth Valencia Botero

Optical and structural studies on SnS films grown by co-evaporation

Polycrystalline SnS thin films were grown on glass substrates using a novel procedure involving a chemical reaction between the precursor species evaporated simultaneously. This is a relatively new material, which exhibits excellent properties to be used as absorbent layer in solar cells. X-ray diffraction (XRD) measurements indicate that the synthesized samples grow in several phases (SnS, SnS2 and Sn2S3) depending upon the deposition conditions. However, through an exhaustive parameter study, conditions were found to grow thin films predominantly in the SnS phase with orthorhombic structure. It was found that this type of compound presents p-type conductivity, a high absorption coefficient (greater than 10 4 cm i1 ) and an energy band gap Eg of about 1.3 eV, indicating that this compound has good properties to perform as absorbent layer in thin film solar cells.

Properties of SnS Thin Films Grown by a Two-Step Process

Polycrystalline SnS thin films were grown on soda-lime glass substrates by conversion into the compound of a Sn thin film deposited by evaporation, by annealing it in the presence of elemental sulfur (sulfurization). This is a relatively new material, which exhibits good properties for its use as absorbent layer in solar cells. X-ray diffraction (XRD) measurements indicate that the synthesized samples grow in several phases (SnS, SnS2 and Sn2S3 ) depending upon the deposition conditions. However, through an exhaustive parameter study, conditions were found to grow thin films predominantly in the SnS phase with orthorhombic structure. It was found that this type of compound presents p-type conductivity, high absorption coefficient (greater than 104 cm-1) and energy band gap Eg of about 1.3 eV, indicating that this compound has good properties to perform as absorbent layer in thin film solar cells. Study of the structural, morphological and optical properties of tin sulphide films, grown in the SnS and SnS2 phases, was carried out from XRD, atomic force microscope (AFM) and spectral transmittance measurements. Theoretical simulation of the XRD pattern with the help of the powdercell package allowed us identifying the phases with a good degree of confidence

Aproximación conceptual a la separación del dióxido de carbono en corrientes de combustión

El dioxido de carbono (CO2) es considerado uno de los principales gases causantes del efecto invernadero, responsable de los fenomenos de calentamiento global y cambio climatico; por ello se han propuesto distintas estrategias de captura y almacenamiento fisico o quimico de CO2, especialmente en las emisiones provenientes de corrientes de combustion. Este documento presenta, en primer lugar, una revision de los procesos de captura de CO2 en procesos de combustion, y, luego, dos escenarios de estudio para la captura de CO2 en un proceso de poscombustion usando metanol como combustible. En el primer escenario se separa el CO2 utilizando absorcion con monoetanolamina, y en el segundo se utiliza destilacion. Los resultados indican que ambas tecnologias son apropiadas, pero que el rendimiento es mayor con la destilacion.