ИСТИНА

Cyclometalated Ir(III) complexes can be considered as more stable analogs of Ru(II) dyes in dye-sensitized solar cells (DSSC). Up to now, there have been many efforts to enhance the absorptivity of Ir(III) dyes, mainly by varying cyclometalated (C^N or ‘antenna’) ligands or by modifying 2,2’-bipyridine-based ‘anchoring’ ligands. We suppose that benzimidazoles, due to their great structural variability, can be used as ‘antenna’ ligands to disclose correlations between the nature of ligands and the photophysical properties of Ir(III) complexes. The second assumption is that we can dramatically change the target optical properties of the complexes by using ‘anchoring’ ligands bearing different types of donor atoms. Herein, we present a joint experimental and theoretical study (X-ray, NMR, MS, UV-Vis, CVA, LS, DFT/ TDDFT) of several series of iridium (III) complexes with 2-arylbenzimidazoles/2-arylphenantroimidazoles and different 'anchoring' ligands. We systematically studied the effect of the ligands structure on the optical and redox properties of the complexes as well as their electronic structures. Several Ir(III) complexes were successfully tested in DSSC. Acknowledgements: this work was supported by Russian Science Foundation (№ 17-73-10084).