Study of electrochemical interfaces by transient reflecting gratings

PHOTOTHERMAL APPLICATIONS OF LASERS: Study of Fast and Ultrafast Photothermal Phenomena at Metal-Liquid Interfaces

“…On the other hand, R gradually decreased and a maximum decrease of about 5% was observed. It was estimated that without material property change, the 5% decrease in R could induce only an 18.5% increase in S. This value was smaller than the 30% increase of Harata et al (65). Figure 4 shows the observed dependence of the TRG waveform on electric potential for Au films in various solutions.…”

“…Harata et al (65), in the first published experiment in which the electrochemical potential and electrolyte solution dependence of subnanosecond time-resolved TRG measurement was observed at a metal-liquid interface, investigated an Au film deposited on a substrate. The inserted trace at the top of Figure 3 shows a typical TRG response measured at the Au film-aqueous H 2 SO 4 solution interface.…”

“…They also demonstrated that hypersonic interfacial waves could be generated and detected by using the surface-restricted TG method. Harata et al (65) applied the TRG method to study electrochemical interfaces of Au-electrolyte solutions where they put some emphasis on fast PT/PA phenomena. They observed the dependence of the intensity and waveform of TRG signal both on electric potential and on electrolyte solution (described below).…”

“…The TRG signal can be used to monitor some dynamic behaviors occurring at the interface, such as relaxation and diffusion of photoexcited species, heat diffusion near the interface and heat conduction across the interfaces, acoustic oscillations and their decay, and other relaxation dynamics. Figure 2 shows a typical subnanosecond time-resolved setup for TRG measurements at a solid-liquid interface under electrochemical potential control (65). A single picosecond visible-light pulse is split into three.…”

“…Measurements of TGs and transient lenses (49)(50)(51)(52) have been used successfully to investigate heat generation in liquid solutions and transparent solids. Measurements of TR and transient reflecting grating (TRG) or impulsive stimulated thermal scattering detected in a reflection geometry (53)(54)(55)(56)(57)(58)(59)(60)(61)(62)(63)(64)(65)(66)(67)(68)(69) are used as fast and ultrafast PT/PA techniques that have applicability to surface and interface investigations for opaque materials. Such measurements (TG, TR, TRG, and transient lens) are, and will continue to be, useful for studying nonradiative relaxation processes just as conventional PT/PA measurements were.…”