Coverage Analysis for the Core/Shell Electrode of Dye-Sensitized Solar Cells

Abstract

In this study, we established a core/shell (C/S) model that evaluates the surface coverage of an overlayer deposited on nanoparticles in terms of X-ray photoelectron spectroscopy signals of the nanoparticles. We used the model to estimate the coverage of Al(2)O(3) shell layers, which were deposited on the nanoporous TiO(2) electrodes of dye-sensitized solar cells (DSSCs) by atomic layer deposition (ALD), as a function of the number of ALD reaction cycles. The surface coverage increased with the average thickness of the Al(2)O(3) shell layers, indicating that the ALD Al(2)O(3) deposition on the nanoporous electrode was via the island growth mode. The power conversion efficiency of the DSSCs was highest after the first ALD reaction cycle for the Al(2)O(3) shell layers, which had a coverage of 0.25, according to the C/S model. The study shows that, to further improve the PCE, optimization of the ALD Al(2)O(3) deposition condition is required so that the surface coverage of the shell layer can be increased at the first ALD reaction cycle.