Cyclometalated Ru(<scp>ii</scp>) complexes with tunable redox and optical properties for dye-sensitized solar cells
Maria A. Lavrova, Sergey A. Mishurinskiy, Daniil E. Smirnov, Paulina Kalle, Ekaterina V. Krivogina, S. A. Kozyukhin, В. В. Емец, Sofia S. Mariasina, Vladimir D. Dolzhenko, Stanislav I. Bezzubov
Abstract
Cyclometalated Ru(ii) complexes with 2-arylbenzimidazole antenna ligands bearing electron-donor/withdrawing substituents and anchoring 4,4'-dimethoxycarbonyl-2,2'-bipyridine have been prepared and their structure, optical and electrochemical properties have been studied. The complexes possess enhanced light-harvesting characteristics compared to those of the standard N719 dye and absorb light up to 750 nm. In addition, they demonstrate reversible redox behavior with Ru3+/Ru2+ potentials being finely tuned by the change of the electron-donating ability of cyclometalated ligands. After a mild hydrolysis of dimethoxycarbonyl groups the excellent optical properties of the complexes remain unchanged and they show good efficiency when tested in dye-sensitized solar cells.