Fig. 4: Image sequence and clustering analysis with mediator.

a An image sequence of the refractive index change for SrTiO3:Rh/ITO/BiVO4:Mo (STOR/ITO/BVOM) in acetonitrile (ACN) in a square region (20 × 50 μm) corresponding to no. 1 in Fig. 1, bottom on the order from nanoseconds to microseconds. The scale bar corresponds to 20 µm. b The categorized mapping of the charge carrier responses of a. An outlier positioned far from all categories was colored in black (#0). c A microscopic image in the same area as in a. d The averaged responses for each category in b are shown. (red: category 1, blue: category 2, green: category 3).