Fig. 3

Photothermal performance of AuNDs. a UV–vis–NIR absorption spectra of different concentrations of AuNDs aqueous solution. b Infrared thermal images of AuNDs aqueous solution (100 µg mL⁻¹) and H₂O under 1064 nm laser irradiation (1.0 W cm⁻²) for 5 min. c Temperature elevation curves of different concentrations of AuNDs aqueous solution under 1064 nm laser irradiation (1.0 W cm⁻²) for 6 min. d Heating curves of AuNDs aqueous solution (100 µg mL⁻¹) under 1064 nm laser irradiation at different power densities. e Photothermal stability of AuNDs aqueous solutions under 1064 nm laser through four cycles of heating and cooling processes. f Black: Temperature profile of the AuNDs solutions irradiated by 1064 nm laser (1.0 W cm⁻²) for 6 min, followed by natural cooling. Blue: The linear fitting of time versus –ln (θ) from the cooling period. g Model of AuNDs. h Experimental and simulated absorption spectra of AuNDs. i Electric near-field enhancement distribution for AuNDs at 1064 nm