Novel non-aggregated hyperbranched phthalocyanines for efficient dye-sensitized solar cells

A series of novel non-aggregated hyperbranched phthalocyanine dyes with different metal centers (H₂, AlCl, Co, Cu, Zn; 1-5) were prepared and utilized as sensitizers of TiO₂ in dye-sensitized solar cells (DSSCs). The zinc substituted hyperbranched phthalocyanine dye 5 exhibited the highest photovoltaic performance, with a power conversion efficiency of at least ~3 times higher than that of any other metal centered counterpart sensitized solar cell. This work provides an easy avenue to solve the aggregation issue of phthalocyanine dyes on TiO₂ surface which hinders them from high photovoltaic performances in DSSCs.