Recent Advances in Phthalocyanine-Based Sensitizers for Dye-Sensitized Solar Cells

Dye-sensitized solar cells (DSSCs) based on nanocrystalline semiconductors have attracted significant attention as lower-cost alternatives to conventional silicon-based solar cells. The photosensitizers are vital components for the development of photovoltaic devices of this kind. Over the years, the most successful sensitizers have been Ru-II polypyridyl complexes, achieving power conversion efficiencies up to 11.5%. However, due to their limited light-harvesting capacity and the high cost of Ru-dyes, efforts have also been directed towards the use of organic dyes. Among the wide range of sensitizers of this kind, phthalocyanines (Pcs) are very attractive because of their light-harvesting properties in the red and near-IR spectral region, as well as their thermal and chemical stability. The performance of Pc-based devices has improved over the years, reaching 5.9%, thanks to rational design of the phthalocyanine structure. In this microreview we review recent advances in the use of phthalocyanines as photosensitizers for DSSC applications.