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Basic information about a final thesisAdditional informationAdditional information about the final thesis follows. Click on the language link to display the information in the desired language.
|Language of final thesis:||English|
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|Title of the thesis:||Photodegradation of Polymer Nanocomposites for Encapsulation of Organic Solar Cells|
|Summary:||Organic Solar Cells (OSCs) are an emerging economically competitive photovoltaic technology that combines manufacturing adaptability, low-cost processing and a light-weight, flexible device end-product. However, commercial use of organic photovoltaics is hindered by its poor overall stability. OSCs, especially the active layer and electrodes, are sensitive to trace quantities of oxygen and humidity, which jointly with light can strongly decrease the performance and the lifetime of the device. The development of encapsulation materials for the photovoltaic module protection with high barrier properties is then one of the challenges for OSC competitiveness in the market. Moreover, these materials have to be stable within the operating life of the cells.
For achieving appropriate cell protection, the improvement of the barrier properties of the polymers is required, which can be reached by the incorporation of passive inorganic particles into the polymer as a matter of to a lengthening of the permeation path due to the tortuous path provoked by the particles. In this work, an alternative approach to introduce active fillers, capable to interact and trap permeant molecules, have been used to improve functional properties of polymer materials for encapsulation applications. For this purpose, zeolites were considered as good candidates due to their good adsorption properties and selectivity.
The main goal of this work was development of EVOH/nanocomposites based on inorganic fillers such as zeolites for potential encapsulation coating for OSC and the study of the durability of their functional properties. The study focuses on one hand on the photooxidation of EVOH copolymers and on the other hand on the photochemical behaviour of the EVOH/zeolite nanocomposites, which was characterised depending on the particle size and the zeolite loading of the materials.
To achieve this goal, the next investigations have been performed and are described in current dissertation:
The characterisation of the initial properties of the materials, EVOH copolymers and EVOH/zeolites nanocomposites. Different properties such as, optical transparency, surface morphology, mechanical and thermal properties, and water uptake properties were investigated. On the base of obtained results, the best candidate(s) for encapsulation of organic solar cells has been proposed.
Next, the materials photostability and the impact of the zeolite particles on the photochemical behaviour of the polymer have been studied. The chemical degradation mechanism of pristine polymers and nanocomposites has been proposed on the base of detected formed upon irradiation photoproducts. The consequences of the photoxidation of the polymer and nanocomposite properties were then investigated.
To conclude, the electrical calcium test and the monitoring of performance of encapsulated OSCs were performed to evaluate the ability of the studied materials to be used as potential candidates for efficient and stable encapsulation coatings for OSCs applications.
|Key words:||encapsulation, EVOH, photostabilty, nanocomposite, zeolite, organic solar cells|
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