Figure 1.

Characterizations of IDSe‐IC2F NPs. a) Schematic illustration of the fabrication process. b) A representative TEM image and DLS result of IDSe‐IC2F NPs. Scale bar: 100 nm. c) Absorption and d) photoluminescence (PL) spectra of IDSe‐IC2F NPs in water; e) photostability test for IDSe‐IC2F NPs (0.1 mg mL⁻¹) and ICG (0.1 mg mL⁻¹) in water. Aqueous dispersion was upon continuous irradiation for 60 min (power density: 1.5 W cm⁻²); f) temperature changes of aqueous dispersion of DSe‐IC2F NPs after irradiation of 793 nm laser with different power densities; g) temperature change curves of aqueous dispersion of IDSe‐IC2F NPs with the irradiation of 793 nm laser on and off (1.5 W cm⁻², five cycles); h) NIR‐II fluorescence image of IDSe‐IC2F NPs (0.5 mg mL⁻¹) in water and in lymphatic fluid (LF) and ICG (0.5 mg mL⁻¹) in LF (optical filter: 1000 nm LP, power density: 7.5 mW cm⁻²).