Fig. 2
a TEM image of PTZ-TQ-AIE dots. b Size distribution of the PTZ-TQ-AIE dots in water. c UV–vis-NIR absorption spectrum and NIR-II fluorescence emission spectrum of the PTZ-TQ-AIE dots in aqueous solution (808-nm excitation). d Photostability of the PTZ-TQ-AIE dots in PBS, FBS, and DMEM under intermittent 808-nm laser (0.25 W/cm2) irradiation for 60 min. e Absorbance and f NIR-II fluorescence emission under continuous 808-nm laser (0.25 W/cm2) irradiation for 30 min. g NIR-II fluorescence images of PTZ-TQ-AIE dots in water (808-nm excitation, 1050, 1150, 1250, 1350, 1450, and 1550 nm band-pass filters). h Signal intensity of PTZ-TQ-AIE dots and ICG through various thicknesses of 1% intralipid solution (excitation: 808 nm, 1050-nm band-pass filter)