Application of polyoxometalate-ionic liquids (POM-ILs) in dye-sensitized solar cells (DSSCs)

Abstract

Polyoxometalates (POMs) as anionic metal oxides are promising candidates for application in dye-sensitized solar cells (DSSCs) due to their peculiar properties including a reversible and multi-electron redox behavior. In this work, four polyoxometalate as ionic liquids (POM-ILs) based on the combination between phosphomolybdate anion (PMo12O40 3−) and organic cations such as [BMIM]+, [BPy]+, [HDPy]+ and [P6,6,6,14]+ were prepared and characterized. A detailed chemical structural elucidation by elemental analysis, ATR-FTIR, 1H and 31P NMR spectroscopies have been performed. These POM-ILs were tested as photosensitizers by adsorption to the photoanode (TiO2 film) for different times (15 min to 17 h). The DSSCs performance can be highly improved comparing the commercially available compound and POM-ILs. The electrodeposition process is an excellent alternative to adsorption in order to improve the overall efficiencies. In general, [BPy]3[PMo12O40] and [P6,6,6,14]3[PMo12O40] are the most promissory compounds for DSSC approaches.