Ruthenium sensitizers based on heteroaromatic conjugated bypiridines for dye-sensitized solar cells

A new ruthenium sensitizer based on a heteroaromatic-4,4'-π-conjugated 2,2'-bipyridine, bearing conjugated π-excessive heteroaromatic rings as donors is presented. Dye-sensitized solar cells have been fabricated based on the novel ruthenium complex [Ru(II)LL'(NCS)2] (L = 4,4'-bis[(E)-2-(3,4-ethylenedioxythien-2-yl)vinyl]-2,2'-bipyridine, L' = 4,4'- (dicarboxylic acid)-2,2'-bipyridine) and their photoelectrochemical properties have been measured under various conditions. Using this sensitizer photovoltaic efficiencies up to 9.1 % under standard global AM 1.5 sunlight were obtained. DFT/TDDFT calculations have been performed for the sensitizer in solution. By calculating the excited states energy and character and comparing the results with the conduction band edge of a model TiO2 nanoparticle, we were able to highlight the factors affecting the measured photovoltaic efficiencies.

[1]  Joseph T. Hupp,et al.  Semiconductor-Based Interfacial Electron-Transfer Reactivity: Decoupling Kinetics from pH-Dependent Band Energetics in a Dye-Sensitized Titanium Dioxide/Aqueous Solution System , 1996 .

[2]  Anders Hagfeldt,et al.  Investigation of influence of redox species on the interfacial energetics of a dye-sensitized nanoporous TiO2 solar cell , 1998 .

[3]  Peng Wang,et al.  A high molar extinction coefficient sensitizer for stable dye-sensitized solar cells. , 2005, Journal of the American Chemical Society.

[4]  S. Mazzucato,et al.  Two-photon absorption of Zn(II) octupolar molecules. , 2007, Physical chemistry chemical physics : PCCP.

[5]  Antonio Tilocca,et al.  Time-dependent DFT study of [Fe(CN)6]4- sensitization of TiO2 nanoparticles. , 2004, Journal of the American Chemical Society.

[6]  M. Grätzel,et al.  Dye Dependent Regeneration Dynamics in Dye Sensitized Nanocrystalline Solar Cells: Evidence for the Formation of a Ruthenium Bipyridyl Cation/Iodide Intermediate , 2007 .

[7]  Guido Viscardi,et al.  Combined experimental and DFT-TDDFT computational study of photoelectrochemical cell ruthenium sensitizers. , 2005, Journal of the American Chemical Society.

[8]  Annabella Selloni,et al.  Time-dependent density functional theory investigations on the excited states of Ru(II)-dye-sensitized TiO2 nanoparticles: the role of sensitizer protonation. , 2007, Journal of the American Chemical Society.

[9]  A. Facchetti,et al.  Novel heteroaromatic-based multi-branched dyes with enhanced two-photon absorption activity. , 2003, Chemical communications.

[10]  Annabella Selloni,et al.  Absorption spectrum and solvatochromism of the [Ru(4,4'-COOH-2,2'-bpy)2(NCS)2] molecular dye by time dependent density functional theory. , 2003, Journal of the American Chemical Society.

[11]  Alan R. Katritzky,et al.  Handbook of heterocyclic chemistry , 1985 .

[12]  A. Facchetti,et al.  A distinctive example of the cooperative interplay of structure and environment in tuning of intramolecular charge transfer in second-order nonlinear optical chromophores. , 2003, Chemistry.

[13]  P. Liska,et al.  Synthesis of novel ruthenium sensitizers and their application in dye-sensitized solar cells , 2005 .

[14]  Renato Bozio,et al.  Novel heterocycle-based two-photon absorbing dyes. , 2002, Organic letters.

[15]  Annabella Selloni,et al.  Influence of the sensitizer adsorption mode on the open-circuit potential of dye-sensitized solar cells. , 2007, Nano letters.

[16]  A. Abbotto,et al.  Push–Pull Organic Chromophores for Frequency‐Upconverted Lasing , 2000 .

[17]  Mohammad Khaja Nazeeruddin,et al.  Conversion of light to electricity by cis-X2bis(2,2'-bipyridyl-4,4'-dicarboxylate)ruthenium(II) charge-transfer sensitizers (X = Cl-, Br-, I-, CN-, and SCN-) on nanocrystalline titanium dioxide electrodes , 1993 .

[18]  R. Hierle,et al.  Design and Synthesis of Push−Pull Chromophores for Second-Order Nonlinear Optics Derived from Rigidified Thiophene-Based π-Conjugating Spacers , 2002 .

[19]  A. Abbotto,et al.  Effect of polarity and structural design on molecular photorefractive properties of heteroaromatic-based push-pull dyes. , 2006, Chemistry.