Thienyl-BOPHY dyes as promising templates for bulk heterojunction solar cells

Abstract

The synthesis and characterization of bis(difluoroboryl)-1,2-bis((1H-pyrrol-2-yl)methylene)hydrazone functionalized with two lateral vinyl-thienyl modules and exhibiting strong absorption in the 400–800 nm window in thin films are reported. Bulk heterojunction solar cells assembled with these dyes and a fullerene derivative (PC₇₁BM), using very small quantities of the additive diiodooctane, give a power conversion efficiency as high as 4.3% with short-circuit current values of 10.9 mA cm⁻², an open-circuit voltage of 0.7 V and external quantum efficiencies higher than 70% over a broad range of wavelengths (580 to 720 nm).