Molecular Arrangement in ultrathin films. Thin films effect in optoelectronic devices
Formación de nuevas estructura moleculares en películas ultrafinas.Preparación de dispositivos electroluminiscentes y fotovoltaicos
Autor
Roldán-Carmona, C.
Director/es
Camacho Delgado, LuisBolink, H.
Editor
Universidad de Córdoba, Servicio de PublicacionesFecha
2014Materia
Ultrathin filmsOrganic electronic
Optoelectric devices
Películas ultrafinas
Dsipositivos electroliminiscentes y fotovoltaicos
Electrónica orgánica
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The evolution of technology has to meet the energetically needs of actual
societies and be respectful for the environment through a sustainable and efficient use
of energy. In this context organic electronic represents a promising technology.
Organic semiconductors are abundant, easy to fabricate and their properties can be
easily tuned. In the form of thin films, they exhibit interesting electronic and magnetic
properties, which in many cases result from the specific molecular organization and
interactions of their components. A low cost organic alternative to the classical
lighting systems are the light-emitting electrochemical cells (LECs),. They require
only one ionic emitting layer, are processed at ambient conditions and are compatible
with air stable electrodes, avoiding rigorous encapsulation in inert atmosphere.
Recently, LECs have shown high luminance, high efficiencies and relatively high
stabilities when specific emitters were used. However, their slow response, their selflimiting
nature and the absence of efficient white light emission, remain the
limitations preventing their application in general lighting. On the other hand, organic
thin films can also be used in photovoltaics, which represents an abundant and low
cost alternative to the silicon established solar cell technology. Nevertheless, their
record efficiency (~ 12%) is still below the requirements for a massive application.
This suggests the need of new materials and configurations to achieve efficiencies
close to those obtained in inorganic Si-cells (20 - 25%) but reducing the
manufacturing costs.
In this Thesis, thin films are studied from two different points of view: as
organized ultra-thin systems containing UV-Vis absorbing molecules, frequently used
in many optoelectronic devices; and as interlayers in LECs and OPV devices. In the
first case, two superficial techniques, the Brewster Angle Microscopy and the UV-Vis
Reflection Spectroscopy, are studied in order to obtain useful information from such
highly organized systems. A new detailed description of the theoretical treatment
needed for each technique is presented, which provides, through a relatively simple...