A series of six new free base porphyrins were synthesized for use as photosensitizers in TiO2 dye-sensitized photo-electrochemical cells. The porphyrin sensitizers are attached to the TiO2 photoelectrode by phosphonic or carboxylic acid anchoring groups. These anchoring groups were placed on different substitution positions on the porphyrin moiety. The new dyes were fully characterized by absorption and emission spectroscopies, electrochemistry and photo-electrochemical spectroscopy. The photo-electrochemical performances of the sensitizers are discussed and compared to the known 5,10,15,20-tetra(4-carboxyphenyl)porphyrin sensitizer. In this study, we show that the nature of the anchoring group (phosphonic or carboxylic acids) has little impact on the photo-electrochemical performance of the cell. However, the substitution position of the anchoring group on the porphyrin strongly influences the monochromatic photon-to-electron conversion efficiency of the resulting cell. The results indicate that the electronic coupling of this type of dye with the d-band of the semiconductor is one of the key parameters in the design of efficient sensitizers.
合成了一系列六种新的游离碱
卟啉,以用作
二氧化钛染料敏化光电
化学电池中的光敏剂。这些
卟啉敏化剂通过
磷酸或
羧酸锚定基团与
二氧化钛光电极相连。这些锚定基团被放置在
卟啉基团的不同取代位置上。新
染料通过吸收和发射光谱、电
化学和光电
化学光谱进行了全面表征。讨论了这些敏化剂的光电
化学性能,并与已知的5,10,15,20-四(4-羧基苯基)
卟啉敏化剂进行了比较。在这项研究中,我们表明,锚定基团的性质(
磷酸或
羧酸)对电池的光电
化学性能影响较小。然而,锚定基团在
卟啉上的取代位置对所产生电池的单色光子转电子效率有较强影响。结果表明,这种
染料与半导体的d带的电子耦合是设计高效敏化剂的关键参数之一。