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dc.contributor.advisorEinarsrud, Mari-Annnb_NO
dc.contributor.advisorSletnes, Malinnb_NO
dc.contributor.advisorBalci, Mustafanb_NO
dc.contributor.advisorMaria, Jeromenb_NO
dc.contributor.authorÅrhus, Åsnenb_NO
dc.date.accessioned2014-12-19T13:25:52Z
dc.date.available2014-12-19T13:25:52Z
dc.date.created2012-04-20nb_NO
dc.date.issued2011nb_NO
dc.identifier517079nb_NO
dc.identifierntnudaim:6528nb_NO
dc.identifier.urihttp://hdl.handle.net/11250/248935
dc.description.abstractSilicon quantum dots were synthesised wet-chemically by three different methods based on reduction of silicon tetrachloride with the reduction agents potassium naphthalide, sodium cyclopentadiene and the alkalide of potassium. The purpose of these quantum dots was to deposit them on a substrate in order to use them as down converters on top of photovoltaic solar cells for enhanced solar cell efficiency. One possible method for the formation of down converting layers is to incorporate quantum dots into silica thin films by deposition of quantum dots in an ethanol based silica sol, followed by spin coating. It is believed that when the quantum dots are water dispersible, this will make it easier to bind them to the silica network, and a good dispersion in the film is facilitated. The different hydrophilic functionalisations investigated were pentenoxy capping, oxidised pentenoxy capping, oxidised acrylic acid capping and ethanolamine capping. Challenges were encountered during the synthesis of water dispersible quantum dots, the most important were related to agglomeration and purification of the quantum dots. This was believed to be due to the tendency of hydrophilic surface groups to attract each other, interaction with the polar solvent and similar solubility characteristics of the quantum dots and the byproduct salts.Si quantum dots with hydrophobic octoxy capping were also synthesised. Dispersions of these quantum dots were deposited onto solid substrates followed by solvent evaporation. This was done to see whether it was possible to deposit the synthesised quantum dots by this simple approach, to investigate the fundamentals upon evaporation, the degree of agglomeration and the byproducts present in the quantum dot dispersions. It was found that agglomeration was very pronounced after the solvent had evaporated and that quite large amounts of byproducts were present in the final quantum dot dispersions. The most important reasons to this were believed to be too weak steric repulsive forces between the particles, too fast evaporation of the solvent and an insufficient purification procedure. For the use of Si quantum dots synthesised wet-chemically as down converters in solar cells, improvements of the particles are needed.nb_NO
dc.languageengnb_NO
dc.publisherInstitutt for materialteknologinb_NO
dc.subjectntnudaim:6528no_NO
dc.subjectMTKJ Industriell kjemi og bioteknologino_NO
dc.subjectMaterialer for energiteknologino_NO
dc.titleWet-chemical deposition of silicon quantum dots for enhanced solar cell efficiencynb_NO
dc.typeMaster thesisnb_NO
dc.source.pagenumber87nb_NO
dc.contributor.departmentNorges teknisk-naturvitenskapelige universitet, Fakultet for naturvitenskap og teknologi, Institutt for materialteknologinb_NO


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