Molecular Design Rule of Phthalocyanine Dyes for Highly Efficient Near-IR Performance in Dye-Sensitized Solar Cells

A series of zincphthalocyanine sensitizers (PcS1618) with different adsorption sites have been designed and synthesized in order to investigate the dependence of adsorption-site structures on the solar-cell performances in zincphthalocyanine based dye-sensitized solar cells. The change of adsorption site affected the electron injection efficiency from the photoexcited dye into the nanocrystalline TiO2 semiconductor, as monitored by picosecond time-resolved fluorescence spectroscopy. The zincphthalocyanine sensitizer PcS18, possessing one carboxylic acid directly attached to the ZnPc ring and six 2,6-diisopropylphenoxy units, showed a record power conversion efficiency value of 5.9% when used as a light-harvesting dye on a TiO2 electrode under one simulated solar condition.