Dye-sensitized solar cells with solvent-free ionic liquid electrolytes

We systematically studied the temperature-dependent physicochemical properties, such as density, conductivity, and fluidity, of 1,3-dialkylimidazolium iodides. In combination with the amphiphilic Z907Na sensitizer, we have found that it is important to use low-viscosity iodide melts with small cations to achieve high-efficiency dye-sensitized solar cells. By employing high-fluidity eutectic-based melts the device efficiencies considerably increased compared to those for cells with the corresponding state of the art ionic liquid electrolytes. We propose a modified Stokes−Einstein equation by correlating ion mobility and fluidity to quantitatively depict the triiodide transport in ionic liquid electrolytes. These studies reveal that the viscosity-dependent transport of triiodide in ionic liquid electrolytes with high iodide concentration can be explained by two parallel processes. Apart from the normal physical diffusion, the coupling process of physical diffusion and bond exchange is responsible for the ob...

[1]  M. Watanabe,et al.  Anomaly of charge transport of an iodide/tri-iodide redox couple in an ionic liquid and its importance in dye-sensitized solar cells. , 2005, Chemical communications.

[2]  Michael Grätzel,et al.  An alternative efficient redox couple for the dye-sensitized solar cell system. , 2003, Chemistry.

[3]  L. Peter,et al.  Determination of the density and energetic distribution of electron traps in dye-sensitized nanocrystalline solar cells. , 2005, The journal of physical chemistry. B.

[4]  S. Zakeeruddin,et al.  Stable mesoscopic dye-sensitized solar cells based on tetracyanoborate ionic liquid electrolyte. , 2006, Journal of the American Chemical Society.

[5]  G. Tammann,et al.  Die Abhängigkeit der Viscosität von der Temperatur bie unterkühlten Flüssigkeiten , 1926 .

[6]  Shuzi Hayase,et al.  Latent gel electrolyte precursors for quasi-solid dye sensitized solar cells , 2005 .

[7]  Peng Wang,et al.  A stable quasi-solid-state dye-sensitized solar cell with an amphiphilic ruthenium sensitizer and polymer gel electrolyte , 2003, Nature materials.

[8]  B. Pilarski.  A new method for N‐alkylation of imidazoles and benzimidazoles , 1983 .

[9]  Michael Grätzel,et al.  Enhance the Performance of Dye-Sensitized Solar Cells by Co-grafting Amphiphilic Sensitizer and Hexadecylmalonic Acid on TiO2 Nanocrystals , 2003 .

[10]  Peng Wang,et al.  A New Ionic Liquid Electrolyte Enhances the Conversion Efficiency of Dye-Sensitized Solar Cells , 2003 .

[11]  H. Dahms.  Electronic conduction in aqueous solution , 1968 .

[12]  Peng Wang,et al.  High efficiency dye-sensitized nanocrystalline solar cells based on ionic liquid polymer gel electrolyte. , 2002, Chemical communications.

[13]  Yuan Wang,et al.  Enhance the optical absorptivity of nanocrystalline TiO2 film with high molar extinction coefficient ruthenium sensitizers for high performance dye-sensitized solar cells. , 2008, Journal of the American Chemical Society.

[14]  Austen Angell,et al.  Binary inorganic salt mixtures as high conductivity liquid electrolytes for >100 °C fuel cells , 2006 .

[15]  Maria Forsyth,et al.  Ionic liquids in electrochemical devices and processes: managing interfacial electrochemistry. , 2007, Accounts of chemical research.

[16]  Frank Lenzmann,et al.  Charge Transport and Recombination in a Nanoscale Interpenetrating Network of n-Type and p-Type Semiconductors: Transient Photocurrent and Photovoltage Studies of TiO2/Dye/CuSCN Photovoltaic Cells , 2004 .

[17]  I. Ruff,et al.  Transfer diffusion. I. Theoretical , 1971 .

[18]  P. Dyson,et al.  How to predict the physical properties of ionic liquids: a volume-based approach. , 2007, Angewandte Chemie.

[19]  Nikos Kopidakis,et al.  Effect of an adsorbent on recombination and band-edge movement in dye-sensitized TiO2 solar cells: evidence for surface passivation. , 2006, The journal of physical chemistry. B.

[20]  Martin A. Green,et al.  Clean electricity from photovoltaics , 2001 .

[21]  Wu Xu,et al.  Ionic liquids: Ion mobilities, glass temperatures, and fragilities , 2003 .

[22]  Tomas Edvinsson,et al.  Comparison of Dye-Sensitized ZnO and TiO2 Solar Cells: Studies of Charge Transport and Carrier Lifetime , 2007 .

[23]  Michael Grätzel,et al.  Influence of 4-guanidinobutyric acid as coadsorbent in reducing recombination in dye-sensitized solar cells. , 2005, The journal of physical chemistry. B.

[24]  A. Hagfeldt,et al.  Molten and Solid Trialkylsulfonium Iodides and Their Polyiodides as Electrolytes in Dye-Sensitized Nanocrystalline Solar Cells , 2003 .

[25]  Ghassan E. Jabbour,et al.  Organic-Based Photovoltaics: Toward Low-Cost Power Generation , 2005 .

[26]  Yuji Wada,et al.  Blue copper model complexes with distorted tetragonal geometry acting as effective electron-transfer mediators in dye-sensitized solar cells. , 2005, Journal of the American Chemical Society.

[27]  Peng Wang,et al.  A solvent-free, SeCN-/(SeCN)3- based ionic liquid electrolyte for high-efficiency dye-sensitized nanocrystalline solar cells. , 2004, Journal of the American Chemical Society.

[28]  D. Macfarlane,et al.  Physical trends and structural features in organic salts of the thiocyanate anion , 2002 .

[29]  Peng Wang,et al.  High-performance dye-sensitized solar cells based on solvent-free electrolytes produced from eutectic melts. , 2008, Nature materials.

[30]  Michael Grätzel,et al.  Effects of ω-Guanidinoalkyl Acids as Coadsorbents in Dye-Sensitized Solar Cells , 2007 .

[31]  H. Pettersson,et al.  The Performance and Stability of Ambient Temperature Molten Salts for Solar Cell Applications , 1996 .

[32]  H. Gores,et al.  Temperature Dependent Impedance Analysis of Binary Ionic Liquid Electrolytes for Dye-Sensitized Solar Cells , 2007 .

[33]  I. Ruff,et al.  Transfer diffusion. III. Kinetics and mechanism of the triiodide-iodide exchange reaction , 1972 .

[34]  C. M. Elliott,et al.  Substituted polypyridine complexes of cobalt(II/III) as efficient electron-transfer mediators in dye-sensitized solar cells. , 2002, Journal of the American Chemical Society.

[35]  M. Spiro,et al.  Tracer diffusion coefficients of I–, I–3, Fe2+ and Fe3+ at low temperatures , 1990 .

[36]  Takayuki Kitamura,et al.  Quasi-solid-state dye-sensitized solar cells using room temperature molten salts and a low molecular weight gelator. , 2002, Chemical communications.

[37]  Peng Wang,et al.  Gelation of ionic liquid-based electrolytes with silica nanoparticles for quasi-solid-state dye-sensitized solar cells. , 2003, Journal of the American Chemical Society.

[38]  M. Grätzel,et al.  Hydrophobic, Highly Conductive Ambient-Temperature Molten Salts. , 1996, Inorganic chemistry.

[39]  Peng Wang,et al.  Tetrahydrothiophenium-Based Ionic Liquids for High Efficiency Dye-Sensitized Solar Cells , 2008 .

[40]  M. Grätzel,et al.  A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films , 1991, Nature.

[41]  Peng Wang,et al.  Charge separation and efficient light energy conversion in sensitized mesoscopic solar cells based on binary ionic liquids. , 2005, Journal of the American Chemical Society.

[42]  Tetsuya Tsuda,et al.  The Application of Room Temperature Molten Salt with Low Viscosity to the Electrolyte for Dye-Sensitized Solar Cell , 2001 .

[43]  M. Watanabe,et al.  Equilibrium potentials and charge transport of an I-/I3- redox couple in an ionic liquid. , 2003, Chemical communications.

[44]  Takurou N. Murakami,et al.  The 2,2,6,6‐Tetramethyl‐1‐piperidinyloxy Radical: An Efficient, Iodine‐ Free Redox Mediator for Dye‐Sensitized Solar Cells , 2008 .

[45]  Peng Wang,et al.  A Binary Ionic Liquid Electrolyte to Achieve ≥7% Power Conversion Efficiencies in Dye-Sensitized Solar Cells , 2004 .

[46]  H. Pettersson,et al.  Electrolytes for dye-sensitized solar cells based on interhalogen ionic salts and liquids. , 2007, Inorganic chemistry.

[47]  A. Walker,et al.  Analysis of photovoltage decay transients in dye-sensitized solar cells. , 2006, The journal of physical chemistry. B.

[48]  D. Richeson,et al.  Hydrogen Bonding Motifs of N,N‘,N‘ ‘-Trisubstituted Guanidinium Cations with Spherical and Rodlike Monoanions: Syntheses and Structures of I-, I3-, and SCN- Salts , 2006 .

[49]  M. Grätzel.  Photoelectrochemical cells : Materials for clean energy , 2001 .

[50]  Ashraful Islam,et al.  Dye-Sensitized Solar Cells with Conversion Efficiency of 11.1% , 2006 .

[51]  H. Gores,et al.  Trialkylsulfonium dicyanamides--a new family of ionic liquids with very low viscosities. , 2005, Chemical communications.

[52]  G. Fulcher,et al.  ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES , 1925 .