Synthesis of carboxylated chlorophyll derivatives and their activities in dye-sensitized solar cells

摘要

Chlorophyll-a derivatives possessing a carboxy group in the substituent at the 3-position were prepared by chemical modification of methyl pyropheophorbide-d bearing the 3-formyl group via a Wittig, Barbier-type, or Knoevenagel reaction. The synthetic carboxylated chlorophyll pigments were employed as dye sensitizers for solar cells and their performances were compared in a conventional device based on a mesoporous titanium dioxide electrode and a liquid electrolyte. The solar power conversion efficiency was suppressed with an increase in the length of the oligomethylene moiety between the chlorin pi-system and the carboxy group, while a corresponding pi-linked ethenylene spacer enhanced the efficiency. (C) 2018 Elsevier Ltd. All rights reserved.