Sensitization of TiO₂ by Phosphonate-Derivatized Proline Assemblies

Abstract

Surface electrochemical and photoelectrochemical measurements on ITO (In(2)O(3):Sn) or TiO(2) of two proline assemblies are reported. Surface coverage on ITO of Pbp-pra(Ru(II)b(2)m)-OH(PF(6))(2) and Bpb-pra(Ru(II)b(2)m)-OCH(3)(CF(3)CO(2))(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/cm(2) for [Ru(bpy)(2)(4,4'-(CO(2)H)(2)bpy)](PF(6))(2) and [Ru(bpy)(2)(4,4'-(PO(3)H(2))(2)bpy)](Br)(2). Incident photon-to-current conversion efficiency (IPCE) measured in Gräztel-type photovoltaic cells are sensitive to subtle structural differences in the assemblies. IPCE values for Pbp-pra(Ru(II)b(2)m)-OH(PF(6))(2) and Bpb-pra(Ru(II)b(2)m)-OCH(3)(CF(3)CO(2))(2) are 2% and <0.1%, which are compared to 23% for both [Ru(bpy)(2)(4,4'-(PO(3)H(2))(2)bpy)](Br)(2) and [Ru(bpy)(2)(4,4'-(CO(2)H)(2)bpy)](PF(6))(2) under the same conditions.

Amphiphilic Ruthenium Sensitizer with 4,4‘-Diphosphonic Acid-2,2‘-bipyridine as Anchoring Ligand for Nanocrystalline Dye Sensitized Solar Cells

“…Grafting sensitizers on the surface of TiO 2 with the phosphonic acid group has been reported earlier by us [4][5][6] and other groups. [7][8][9][10][11][12][13] Recently, we have demonstrated the significance of using an amphiphilic polypyridyl ruthenium sensitizer to achieve unprecedented stability in DSCs at elevated temperatures. 14 Also, self-assembling of ω-alkylphosphonic acids on a wide range of metal oxide surfaces has been of great scientific and practical interest due to the ability to form robust and compact monolayers.…”

Immobilization of a High‐Valent Rhenium Complex on an Indium‐Doped Tin‐Oxide Electrode: Enhanced Catalytic Activity of a trans‐Dioxorhenium(V) Complex in Electrochemical Oxidation of Alcohols

“…[Ru(2,2Ј-bipyridyl) 2 (2,2Јbipyridyl-4,4Ј-dicarboxylic acid)] 2ϩ ϭ 1.5 ϫ 10 Ϫ10 mol/cm 2 ; [9] and [Ru(2,2Ј-bipyridyl) 2 (2,2Јbipyridyl-4,4Ј-diphosphonic acid)] 2ϩ ϭ 2.5 ϫ 10 Ϫ10 mol/cm 2 . [9] Thus, the employed Re V complex [1] ϩ is believed to form a monolayer structure on the ITO electrode surface.…”

“…[9] Thus, the employed Re V complex [1] ϩ is believed to form a monolayer structure on the ITO electrode surface. The modified electrodes exhibit interesting catalytic behavior in the electrochemical oxidation of 1-phenylethanol.…”

Hybrid Organic-Inorganic Materials Based on Organophosphorus Derivatives

“…The grafting of OPCA to metal oxide surfaces is well documented. OPCA bind strongly to the surface of transition metal oxides such as TiO 2 [119][120][121][122][123][124][125][126][127][128][129][130][131], ZrO 2 [120,121,127,130,132,133], SnO 2 [125,126,134], Ta 2 O 5 [127,135], Nb 2 O 5 [127], Fe 2 O 3 [136], or indium-tin oxide (ITO) [137][138][139]. OPCA also exhibit good affinity for Al 2 O 3 [121,[140][141][142][143][144][145] as well as anodized Al [127,146].…”

“…In the separation domain, OPCA have been used to modify inorganic membranes [120,141,194,195] or supports for chromatography [120,[196][197][198]. Several recent works have been devoted to the bonding of transition metal complexes (e.g., ruthenium(II) polypyridine) to nanocrystalline TiO 2 using phosphonic acid anchors for the elaboration of photovoltaic [119,122,123,138,199] and optical devices [200][201][202]. There are very few examples of OPCA based hybrid materials in heterogeneous catalysis, although OPCA allow to bind organometallic catalysts [145,203,204] and enzymes [197,205] to a large variety of supports other than SiO 2 .…”