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Nanoparticules à base d'oxyde de titane par pyrolyse laser : synthèse, proprietés et application au photovotaïque

Abstract : This work is related to the development of new TiO2 porous photo-electrodes based on nanopowders synthesized by laser pyrolysis for application in solid-state dye-sensitized solar cells. Two different types of TiO2 powders were synthesized: TiO2 nanoparticles doped with different levels of nitrogen, and TiO2/MWNTC (Multi Wall Carbon Nanotubes) nanocomposites. In the first case, the efficiency of the solar cells is dependent on the nitrogen amount in the powder, in relation with the localization of the dopants in the TiO2 structure. High nitrogen contents are associated with high defect densities at the TiO2 nanoparticle surface, leading to intense charge recombination. Although this effect limits the performance of the cells, it can be counterbalanced by an increased electrical conductivity due to the presence of N atoms. Finally, for moderate doping levels, the incorporation of nitrogen can improve the efficiency of the cells, compared to reference devices. Regarding the use of TiO2/MWNTC nanocomposites, the one step synthesis by laser pyrolysis from a precursor mixture including MWNTC leads to nanopowders where nanotubes appear very homogeneous dispersed of. The nanotubes are also highly coated with TiO2 particles, improving their electrical interactions with the TiO2 particles. The efficiencies of the solar cells made from such composites are found to be 20% larger than that of reference cells. This improvement is mainly attributed to faster charge collection and reduced charge recombination rates.
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https://tel.archives-ouvertes.fr/tel-01084022
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Submitted on : Tuesday, November 18, 2014 - 1:17:00 PM
Last modification on : Friday, March 5, 2021 - 3:08:29 PM
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  • HAL Id : tel-01084022, version 1

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Jin Wang. Nanoparticules à base d'oxyde de titane par pyrolyse laser : synthèse, proprietés et application au photovotaïque. Matériaux. Université Paris Sud - Paris XI, 2014. Français. ⟨NNT : 2014PA112222⟩. ⟨tel-01084022⟩

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