Fig. 3: Mechanism investigation for ultrasound-responsive CNDs.

a-c Transmission electron microscope (TEM) images of CNDs after being sonicated at different times. d Illustration of the nano-assembly process of CNDs and cyclodextrin under different ultrasonic times. e X-ray diffraction (XRD) of CNDs after being sonicated at different times. f C 1 s spectra of CNDs after being sonicated at different times. g Phosphorescence spectra of the ultrasound-responsive CNDs before and after grounding. h EPR spectra of ultrasound-responsive CNDs before and after grounding. i Proposed mechanism for ultrasound-responsive phosphorescence of CNDs