LAUSR

Abstract The synthesis of seven iridium complexes where aryl-1,2,3-triazole (Ar-tz) moieties act as cyclometalating ligands with 2,2′-bipyridyl-4,4′-dicarboxylic acid (dcb) as a N^N ancillary/anchoring ligand, is described. The new dye complexes [Ir(Ar-tz) 2 (dcb)][PF 6 ] ( AS1-7 ) were prepared in a two stage procedure with iridium-chloride dimer isolation. DFT analysis together with photophysical investigations reveal how using different substituents on the phenyl ring, or a different aryl system, lead to the tuning of the absorption and emission properties of these complexes. Computational studies therefore demonstrate an ideal HOMO-LUMO directionality for the [Ir(Ar-tz) 2 (dcb)] + framework, promoting a favourable electron transfer into the TiO 2 conduction band upon photoexcitation. Preliminary unoptimized tests on TiO 2 DSSCs have been carried out which show similar photovoltaic performance to the [Ir(ppy) 2 (dcb)][PF 6 ] (ppy = 2-phenylpyridine) benchmark.