Charge Transport in Bare and MgO-coated TiO2 Thin Films and in Dye-Sensitized Solar Cells: Effect of Film Thickness

Citation:
Waita SM, Ogacho AA, Aduda BO. "Charge Transport in Bare and MgO-coated TiO2 Thin Films and in Dye-Sensitized Solar Cells: Effect of Film Thickness.". In: Electroceramics (ICE 2007). Arusha Tanzania; 2007.

Date Presented:

30th July – 3rd

Abstract:

Electron transport in bare and MgO-coated colloidal TiO2 thin films has been studied using surface photovoltage spectroscopy (SPS), while the charge transport in dye-sensitized solar cells based on annealed titanium dioxide films prepared by oblique reactive DC magnetron sputtering has been studied by the intensity–modulated photocurrent and photovoltage spectroscopy (IMPS and IMVS). The SPS results obtained showed a dispersive electron transport with strongly retarded photocurrents, and the electron diffusion coefficient measured in a parallel plate capacitor arrangement was observed to be strongly dependent on film thickness. Further, the MgO buffer layer initially enhanced the effective diffusion coefficient but beyond certain MgO concentration the diffusion coefficient decreased. From the IMPS/IMVS studies, the electrons transit more rapidly at higher light intensities whereas the electron lifetime diminishes with increase in light intensity. The electron transit and lifetimes were found to increase with film thickness. Grain boundaries with associated trap and / or energy barriers and their passivation by MgO are proposed to explain the observed transport properties.

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