Comparison between Bi₂WO₆ and TiO₂ Photoanodes in Dye-Sensitized Solar Cells: Experimental and Computational Studies

Abstract

Dye-sensitized solar cells (DSSCs) demonstrate a clean and cheap technology to harness solar energy efficiently and have been studied in a large scale for safe and reliable energy supply. This research focuses on the experimental and computational study of DSSCs based on a different and novel metal oxide, bismuth tungstate (Bi2WO6), semiconductor as an electron conductor. This work is divided into four main topics: (1) the search for an appropriate Bi2WO6 nanostructure for better dye absorption, (2) comparison between Bi2WO6 and TiO2 as photoanodes, (3) the impact of the semiconductor morphology on the performance of DSSCs, and (4) the study of the structural and dynamical properties of the dye solution and also the electrolyte mixture near electrodes in DSSCs. This study pointed out the poor properties of ruthenium-complex dye as sensitizers for Bi2WO6 and the great effect of Bi2WO6 surface charge on dye adsorption. The best performance of Bi2WO6 DSSC was obtained for morphologies synthesized at pH = 1, which can be attributed to the less negative surface charges of Bi2WO6 nanoparticles. Another important part of this paper was devoted to study the electrolyte distribution between anode and cathode surfaces for both TiO2 and Bi2WO6 DSSCs. To our knowledge, acetonitrile-based electrolyte interactions with the Bi2WO6 photoanode have not been explored to date.