Sensitization of TiO2 by phosphonate-derivatized proline assemblies

Trammell SA; Moss JA; Yang JC; Nakhle BM; Slate CA; Odobel F; Sykora M; Erickson BW; Meyer TJ

Inorganic Chemistry, Vol.38, No.16, 3665-3669, 1999

Trammell SA, Moss JA, Yang JC, Nakhle BM, Slate CA, Odobel F, Sykora M, Erickson BW, Meyer TJ

Surface electrochemical and photoelectrochemical measurements on ITO (In2O3:Sn) or TiO2 of two proline assemblies are reported. Surface coverage on ITO of Pbp-pra(Ru(II)b(2)m)-OH(PF6)(2) and Bpb-pra(Ru(II)b(2)m)-OCH3(CF3CO2)(2) are (1.5-2.4) x 10(-10) mol/cm(2), comparable to monolayer coverages of (1.5-2.5) x 10(-10) mol/cm2 for [Ru(bpy)(2)(4,4'-(CO2H)(2)bpy)](PF6)(2) and [Ru(bpy)(2)(4,4'-(PO3H2)(2)bpy)](Br)(2). Incident photon-to-current conversion efficiency (IPCE) measured in Graztel-type photovoltaic cells are sensitive to subtle structural differences in the assemblies. IPCE values for Pbp-pra(Ru(II)b(2)m)-OH(PF6)(2) and Bpb-pra(Ru(II)b(2)m)-OCH3(CF3CO2)(2) are 2% and <0.1%, which are compared to 23% for both [Ru(bpy)(2)(4,4'-(PO3H2)(2)bpy)](Br)(2) and [Ru(bpy)(2)(4,4'-(CO2H)(2)bpy)](PF6)(2) under the same conditions.

Keywords:ELECTRON-TRANSFER;TITANIUM-DIOXIDE;ENERGY-CONVERSION;METALCOMPLEXES;LIGHT;FILMS;ELECTRICITY;EFFICIENCY;SURFACES;DYNAMICS