Cosensitizers for simultaneous filling up of both absorption valleys of porphyrins: a novel approach for developing efficient panchromatic dye-sensitized solar cells

XS1–XS3 have been synthesized by introducing an auxiliary acceptor into D–π–A dyes for simultaneous filling up of both absorption valleys of porphyrin dyes at around 550 and 380 nm. Thus, panchromatic DSSCs with the highest efficiency of 10.75% were achieved by cosensitization. This work provides a strategy for designing cosensitizers for porphyrin dyes.