Paper EH-ThM3
Applications of pure ZnO and the Mn-doped ZnO on Dye Sensitized Solar Cells

Thursday, December 11, 2014, 8:40 am, Room Lehua

Mn-doped ZnO nanopowders have been prepared by the sol–gel technique using zinc and manganese (II) acetates as precursors. The crystalline structural investigations reveal that as prepared nanostructures with low Mn doping concentration have single hexagonal phase and are grown along the preferred c-axis. The chemical bonding structure in Mn-doped ZnO nanopowders was examined using X-ray photoelectron spectroscopy techniques, which indicate substitution of Mn²⁺ ions into Zn²⁺ sites in ZnO lattice. Temperature-dependent Raman spectra of the nanocrystals displayed suppression of luminescence and enhancement in full width at half maximum in pure ZnO nanocrystals with increase in temperature, which suggests an enhancement in particle size at elevated temperature. Furthermore, the magnetic measurement of Mn-doped ZnO nanostructures exhibits the ferromagnetism at room temperature.

The characteristics of dye-sensitized solar cells (DSSCs) with pure ZnO and Mn-doped ZnO nanopowders have also been investigated. The enhancement of the performance of DSSCs achieved using Mn-doped ZnO nanopowders is attributable to the introduction of the spontaneous polarization direction of ferroelectric materials with the electric field which will efficiently block the back transfer of electron from fluorine doped tin oxide to the I^-/I₃^- redox couple.