Yuly Kusumawati : Effects of Oxide Nanoparticle Size and Shape on Electronic Structure, Charge Transport, and Recombination in Dye-Sensitized Solar Cell Photoelectrodes
Yuly Kusumawati S.Si, M.Si
The Journal of Physical Chemistry C
Forced hydrolysis in polyol medium is a versatile synthesis method for the preparation of metal oxide particles with controlled properties. We investigated the D149-dye-sensitized solar cell (DSSC) performance of ZnO film electrodes prepared with four different types of nanoparticles having various sizes and morphologies. The photoanode dye loading has been determined, and the cells have been studied by impedance spectroscopy (IS) at various applied voltages. From the analysis of the IS spectra, the key functioning parameters of the various photoelectrodes such as trap-state distribution, electron-transfer time, and electron lifetime have been determined. The particle shape and size deeply influence the dye loading and the electronic structures of the trap-state levels localized below the conduction band minimum. Low open circuit voltage and fill factor are found in the case of small (8 nm) spherical particles because of very deep energy states related to large particle necking and high density of grain boundaries. On the other hand, layers made of sintered large hexagonal rodlike particles (35 nm in diameter) of high crystalline quality show satisfying dye loading, shallower energy trap states, higher conductivity, and very high charge-collection efficiency.