A new ruthenium polypyridyl dye, TG6, whose performance in dye-sensitized solar cells is surprisingly close to that of N719, the ‘dye to beat’ for 17 years
作者:Farah Matar、Tarek H. Ghaddar、Kate Walley、Tracy DosSantos、James R. Durrant、Brian O'Regan
DOI:10.1039/b808255c
日期:——
A new ruthenium polypyridine sensitizer for dye-sensitized solar cells (DSSCs) is proposed containing a hexasulfanylâstyryl-modified bipyridyl group as an ancillary ligand. The advantages of this dye are the much larger absorption coefficient and the small shift of the absorption envelope to the red. We compare this new dye, TG6 (cis-bis(thiocyanato)(2,2â²-bipyridyl-4,4â²-dicarboxylato)4,4â²-bis[2-(4-hexylsulfanylphenyl)vinyl]-2,2â²-bipyridine}ruthenium(II) mono(tetrabutylammonium) salt), to the current best-performing dye, N719 (cis-bis(thiocyanato)bis(2,2â²-bipyridine-4,4â²-dicarboxylato)ruthenium(II) bis(tetrabutylammonium) salt). We have applied a suite of evaluation tools including: varying the electrolyte, varying the TiO2 film thickness, charge density and recombination rate constant measurements, fluorescence lifetime and magnitude, and transient absorption techniques. The combined results indicate that TG6, as presently constructed, can surpass the performance of N719 under some conditions, but is likely to need some modification before surpassing cells designed to give record energy efficiency using N719. The higher absorption coefficient may be relevant to mass-produced DSSCs on metal where thinner TiO2 films are advantageous. The main disadvantage is the slight catalysis of the electron/electrolyte recombination, which is possibly due to the extended Ï-system. A factor that requires further optimization involves the complex interaction of the slightly lower LUMO position, the composition of the electrolyte, the band edge position of the TiO2, and the electron injection rate. We show why the maximum output from TG6 cells will not occur using the exact electrolytes used to maximize N719 cells.
提出了一种新的铑-多吡啶敏化剂,用于染料敏化太阳能电池(DSSCs),它包含一个六硫氨基-苯乙烯改性的双吡啶基团作为辅助配体。这种染料的优点在于其更大的吸收系数和吸收包络线向红区的微小偏移。我们将这种新染料TG6(顺-双(硫氰酸根)(2,2'-双吡啶-4,4'-二羧酸盐)4,4'-双[2-(4-己基硫氨基苯基)乙烯]-2,2'-双吡啶}铑(II)单(四丁基铵)盐)与当前表现最佳的染料N719(顺-双(硫氰酸根)双(2,2'-双吡啶-4,4'-二羧酸盐)铑(II)双(四丁基铵)盐)进行比较。我们应用了一系列评估工具,包括:改变电解质、改变TiO2薄膜厚度、测量电荷密度和重组速率常数、荧光寿命和强度及瞬态吸收技术。综合结果表明,按当前构造的TG6在某些条件下可以超过N719的性能,但在超越针对使用N719来达到记录能量效率的电池之前,可能需要一些改进。更高的吸收系数可能与在金属上大规模生产的DSSCs相关,因为更薄的TiO2薄膜更具优势。主要缺点是电子/电解质重组的轻微催化,这可能是由于扩展的π-体系导致的。需要进一步优化的一个因素涉及稍微较低的LUMO位置、电解质成分、TiO2的带边位置和电子注入速率之间的复杂相互作用。我们展示了为何TG6电池的最大输出不会使用与优化N719电池相同的电解质。