Park Hyunwoong, Bae Eunyoung, Lee Jae-Joon, Park Jaiwook, Choi Wonyong
School of Environmental Science and Engineering and Department of Chemistry, Pohang University of Science and Technology, Pohang 790-784, South Korea.
J Phys Chem B. 2006 May 4;110(17):8740-9. doi: 10.1021/jp060397e.
The effects of the number of anchoring groups (carboxylate vs phosphonate) in Ru-bipyridyl complexes on their binding to TiO(2) surface and the photoelectrochemical performance of the sensitized TiO(2) electrodes were systematically investigated. Six derivatives of Ru-bipyridyl complexes having di-, tetra-, or hexacarboxylate (C2, C4, and C6) and di-, tetra-, or hexaphosphonate (P2, P4, and P6) as the anchoring group were synthesized. The properties and efficiencies of C- and P-complexes as a sensitizer depended on the number of anchoring groups in very different ways. Although C4 exhibited the lowest visible light absorption, C4-TiO(2) electrode showed the best cell performance and stability among C-TiO(2) electrodes. However, P6, which has the highest visible light absorption, was more efficient than P2 and P4 as a sensitizer of TiO(2). The surface binding (strength and stability) of C-complexes on TiO(2) is highly influenced by the number of carboxylate groups and is the most decisive factor in controlling the sensitization efficiency. A phosphonate anchor, however, can provide a stronger chemical linkage to TiO(2) surface, and the overall sensitization performance was less influenced by the adsorption capability of P-complexes. The apparent effect of the anchoring group number on the P-complex sensitization seems to be mainly related with the visible light absorption efficiency of each P-complex.
系统研究了钌联吡啶配合物中锚定基团（羧酸盐与膦酸盐）的数量对其与TiO₂表面结合以及敏化TiO₂电极光电化学性能的影响。合成了六种以二羧酸、四羧酸或六羧酸（C2、C4和C6）以及二膦酸、四膦酸或六膦酸（P2、P4和P6）为锚定基团的钌联吡啶配合物衍生物。C-配合物和P-配合物作为敏化剂的性质和效率以非常不同的方式取决于锚定基团的数量。尽管C4的可见光吸收最低，但C4-TiO₂电极在C-TiO₂电极中表现出最佳的电池性能和稳定性。然而，可见光吸收最高的P6作为TiO₂的敏化剂比P2和P4更有效。C-配合物在TiO₂上的表面结合（强度和稳定性）受羧酸盐基团数量的影响很大，是控制敏化效率的最决定性因素。然而，膦酸酯锚定基团可以与TiO₂表面提供更强的化学连接，并且整体敏化性能受P-配合物吸附能力影响较小。锚定基团数量对P-配合物敏化的明显影响似乎主要与每个P-配合物的可见光吸收效率有关。
