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

Abstract

A new amphiphilic polypyridyl ruthenium complex, cis-Ru(dpbpy)(dnbpy)(NCS) 2 (dpbpy ) 4,4′-diphosphonic acid-2,2′-bipyridine; dnbpy ) 4,4′-dinonyl-2,2′-bipyridine), was synthesized and demonstrated as an efficient sensitizer. The sensitizer was characterized by NMR, voltammetry, ATR-FTIR, resonance Raman, as well as electronic absorption and emission spectra. Nanocrystalline dye-sensitized solar cells (DSCs) with this new sensitizer generated g8.0% power conversion efficiencies under illumination with simulated air mass 1.5 sunlight. This is the first time such a high solar-to-electricity power conversion efficiency for DSCs has been reached by a sensitizer bearing non-carboxylic acid anchoring groups. Additionally, the devices exhibited excellent stability under light soaking at 55 to 60°C. Time-resolved nanosecond laser experiments revealed that the dye regeneration rate of this new sensitizer seems to be quite similar but the charge recombination is significantly slower in comparison to the analogues carboxylated sensitizer.

Optimizing Dyes for Dye‐Sensitized Solar Cells

“…The majority of dyes are linked to the TiO 2 semiconductor through acidic groups-mostly carboxylic acid or, less commonly, phosphonic acid linkers [46] -although a variety of other moieties also have been used. [47,48] Carboxylic acid groups can form ester linkages with the surface of the metal oxide to provide a strongly bound dye and good electronic communication between the two parts.…”

Kinetics of Fe(II) reduction of cis‐halogeno(dodecylamine) bis(ethylenediamine)‐ cobalt(III) complex ion in aqueous solutions

“…Numerous studies have been performed, addressing the dependence of electron transfer on different environments including metalloproteins [8], vitamin B 12 [9], liquids [10,11], micelles [12,13], vesicles [14], and DNA [7]. Electron transfer in restricted geometry system such as micelles, reverse micelles, and vesicles attracts a great deal of interest because of their potential to prolong the lifetime of charge-transfer states, a goal of electrontransfer studies aiming to utilize solar energy [15,16] and as molecular switches [17,18]. When the nature of the chemical reaction in organized system is discussed, in particular electron-and proton-transfer reactions, the influence of the local microenvironment on the reactivity, the local concentrations, and the driving force have to be considered.…”

Ruthenium Polypyridyl Sensitisers in Dye Solar Cells Based on Mesoporous TiO2

“…A strategy to prevent the hydrolysation of the link between the dye and TiO 2 is the substitution of carboxylic acid groups by more stable linkers such as phosphonic acid. [19,122] Furthermore, dyes attached to the surface of the metal oxide can be desorbed by the presence of water in the electrolyte, which is obviously a concern for the long-term stability of DSSCs. [123] The incorporation of hydrophobic alkyl chains to the pyridyl ligand can decrease dye desorption and increase cell stability by preventing the accumulation of water molecules near the TiO 2 surface (Figure 25).…”