[A] is the intensity of the peak, [A]0 is the initial intensity, kf is the fractal kinetics constant, t is time, and h is the fractal order. All the data studied here was fitted using this equation, and the overall fit quality is outstanding. The principal extracted value is kf, which indicates how fast the reaction is. The plot of kfvs. the excitation wavelength for the three materials is given in Figure . The results show that black Au exhibited an overall faster reaction than the AuNFs for all the studied wavelengths. In addition, the reaction exhibited a faster rate at 532 nm, and a slowest rate at 785 nm. In contrast, AgNPs present faster kinetics at 488 nm. This is expected since the typical plasmonic resonance of the Au NPs and AgNPs are located around 520 and 420 nm, respectively. These results show the dependence of the reaction rate on the plasmon resonance of nanoparticles, which confirm the plasmonic nature of the crosslinking reaction of the assembled MBD molecules.