Photocurrent generation by MWCNTs functionalized with bis-cyclometallated Ir(iii)- and trisbipyridyl ruthenium(ii)- polypyrrole films

Abstract

A novel [bis(2-phenylpyridyl)(pyrrole-ether bipyridyl) Ir(III)]PF₆ complex bearing pyrrole groups was synthesized, characterized and electropolymerized at Pt and MWCNT electrodes. MWCNT deposits present a nanostructured porous surface that induces a higher polymerization yield and enhanced surface concentration of the Ir complex. The photoelectrochemical properties of bis-cyclometallated Ir(III) polypyrrole films were compared with those of Ru(II) polypyrrole films electrogenerated from the parent [bis(bipyridyl)(pyrrole-ether bipyridyl) Ru(II)](PF₆)₂ complex. Ir(III)- and Ru(II) polymer/MWCNT photoelectrodes exhibit anodic photocurrent densities of 12.3 and 19.5 μA cm⁻², respectively, that are higher than those recorded with similar films on Pt electrodes. In addition, bis-cyclometallated Ir(III)-polypyrrole electrodes exhibit similar photoelectrochemical properties to trisbipyridyl Ru(II) polypyrrole films.