Studies on Electrodes Modified by Noble Metal Nano-Particles Covered with Dye Aggregate

菁染料在贵金属纳米粒子（j聚集体/贵金属纳米粒子）上的j聚集体的Frenkel激子吸收带的强度受纳米粒子中激发的表面等离子体激元的影响。在本研究中，我们尝试在电极上构建j聚集体/贵金属纳米颗粒，并考察了该电极用于光电化学方法的可能性。在本研究之前，我们已经在云母上制备了具有原子平面的贵金属纳米粒子。然而，在使用其他表面比云母更粗糙的衬底的情况下，制备纳米颗粒的最佳条件就不同了。因此，我们首先寻找真空蒸发镀膜制备纳米粒子的最佳条件。因此，虽然颗粒的尺寸分布不是很好，但我们可以在衬底上制备出具有理想等离子体带的贵金属纳米颗粒。通过卤化法和氨基硫醇SAMs法，证实了菁菁染料j聚集体可以吸附在贵金属纳米颗粒上。然而，当含纳米颗粒的衬底浸泡在溶液中时，往往会发生纳米颗粒从衬底上剥离的现象。采用氩离子溅射涂层在基片上制备贵金属纳米颗粒，与真空蒸发涂层相比，纳米颗粒在浸没过程中从基片上脱落的情况更少。因此，在电极上构建j聚集体/贵金属纳米粒子并检测其光电电化学性能成为可能。另一方面，我们测量了j聚集体/贵金属纳米粒子体系的荧光衰减曲线和瞬态吸收光谱，获得了系统激发态弛豫动力学的新见解。由于光电化学过程是从系统的激发态开始的，因此了解其动力学特性是非常重要的。

The strength of absorption band of Frenkel exciton in J-aggregates of cyanine dyes on noble metal nano-particles (J-aggregate/noble metal nano-particles) is affected by the surface plasmon excited in the nano-particles. In this study, we tried to construct the J-aggregate/noble metal nano-particles on electrode, and we examined the possibility of the electrode for photo-electrochemical methods. Until this study, we have prepared the noble metal nano-particles on mica, which have the atomically flat surface. However, in the case of using other substrate whose surface would be rougher than mica, the best condition for making nano-particles was different. Therefore, we first searched for the best condition to make nano-particles by vacuum evaporation coating. As a result, although the size distribution of the particles was not so good, we could prepare the noble metal nano-particles, which have a desired plasmon band, on the substrate. We confirmed that J-aggregate of cyanine dye could adsorb on the noble metal nano-particles by using halogenations method or SAMs of aminothiol. However, the delamination of nano-particles from the substrate often occurred when the substrate with nano-particles was immersed in solutions. In case of using Ar ion sputter coating to prepare the noble metal nano-particles on the substrate, the nano-particles were less delaminated from the substrate during immersing process than the case of using vacuum evaporation coating. As a result, it became to possible to construct the J-aggregate/noble metal nano-particles on the electrode and to examine the photo-electrochemical properties. On the other hand, we measured the fluorescence decay curves and transient absorption spectra of the J-aggregate/noble metal nano-particles system, and obtained the new insight for the relaxation dynamics of the excited state of the system. Because photo-electrochemical process starts from the excited state of the system, it is important to know the dynamics.