Performance of dye-sensitized solar cells based on novel sensitizers bearing asymmetric double D−π−A chains with arylamines as donors

Three novel, metal-free organic sensitizers bearing two asymmetric double donor-π-acceptor (D-π-A) chains (DC1-3), each, and a reference dye containing single D-π-A chain (SC) with cyanoacrylic acid as electron acceptor are synthesized. Their photophysical, electrochemical properties and the performances of the corresponding dye-sensitized solar cells (DSSCs) are further investigated. The dyes, DC1, DC2 and DC3 contain one chain with diphenylamine and another chain with carbazole or phenothiazine as electron donor, while diphenylamine is only employed as electron donor in SC. Compared to the inferior solar energy to electricity conversion efficiency (η) of 2.82%, 4.66% and 3.80%, respectively, for the DSSCs based on DC1, DC2 and SC, the DC3 sensitized cell gives η of 5.19% under standard global AM 1.5 solar condition (100 mW cm−2) due to its broader and more intensive absorption in the UV–visible region.

► Three organic dyes bearing two asymmetric D-π-A chains are synthesized.
► Their absorption range is broadened.
► Their absorption intensity is enhanced.
► Their DSSCs exhibit higher efficiency.