Investigating the Electron Transport and Light Scattering Enhancement in Radial Core-Shell Metal-Metal Oxide Novel 3D Nanoarchitectures for Dye Sensitized Solar Cells

<p>Dye-sensitized solar cells (DSSCs) have attained considerable attention during the last decade because of the potential of becoming a low cost alternative to silicon based solar cells. Electron transport is one of the prominent processes in the cell and it is further a complex process because the transport medium is a mesoporous film. The gaps in the pores are completely filled by an electrolyte with high ionic strength, resulting in electron-ion interactions. Therefore, the electron transport in these so called state-of-the-art systems has a practical limit because of the low electron diffusion coefficient (D_n) in this mesoporous film photoanode. This work focuses on the influence of the advanced core-shell nanoarchitecture geometry on electron transport and also on the influence of electron-ion interactions. In order to achieve the proposed goals, DSSCs based on ordered, highly aligned, 3D radial core-shell Au-TiO₂ hybrid nanowire arrays were fabricated, using three different approaches. J-V, IPCE, and EIS characteristics were studied. The efficiency, light scattering and charge transport properties of the core-shell nanowire based devices were compared to TiO₂ nanotube as well as TiO₂ mesoporous film based DSSCs. The Au nanowires inside the crystalline TiO₂ anatase nanoshell provided a direct conduction path from the TiO₂ shell to the TCO substrate and improved transport of electrons between the TiO₂ and the TCO. The optical effects were studied by IPCE measurement which demonstrated that Au-TiO₂ nanowires showed an improved light harvesting efficiency, including at longer wavelengths where the sensitizer has weak absorption. The metal nanostructures could enhance the absorption in DSSCs by either scattering light enabling a longer optical path-length, localized surface plasmon resonance (LSPR) or by near-field coupling between the surface plasmon polariton (SPP) and the dye excited state. Rapid, radial electron collection is of practical significance because it should allow alternate redox shuttles that show relatively fast electron-interception dynamics to be utilized without significant sacrifice of photocurrent. A combination of improved electron transport and enhanced light harvesting capability make Au-TiO₂ core-shell nanowire arrays a promising photoanode nanoarchitecture for improving photovoltaic efficiency while minimizing costs by allowing thinner devices that use less material in their construction.</p>

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Year

2012

Author dc:creator

• Sahu, Gayatri

Contributors dc:contributor

• Tarr Mathew A
• Wiley John B
• Caruntu Gabriel

• "TiO2" "Dye Sensitized Solar Cells" "Au" " Core-Shell Nanowire" "Plasmonics" "nanotube"
• Inorganic Chemistry
• Materials Chemistry

Repository record dc:identifier

https://scholarworks.uno.edu/td/1478

OAI identifier oai:identifier

oai:scholarworks.uno.edu:td-2437