Fig. 3
In vitro photothermal-conversion assessment of HCu. a UV–vis-NIR spectra of HCu at different concentrations (6.25, 12.5, 25, and 50 μg/mL) in aqueous solution. b Temperature changes of HCu aqueous solution with NIR laser (808 nm, power density: 1.5 W/cm2) irradiation at elevated concentrations (12.5, 25, 50, and 100 μg/mL). c Photothermal-heating curves of HCu dispersed in the aqueous solution irradiated by different power intensities (0.75, 1.0, 1.25, and 1.5 W/cm2) of NIR laser at the wavelength of 808 nm. d Photothermal performance of HCu dispersed in aqueous solution under NIR irradiation; the laser was turned off when the temperature was stable. e Time constant for heat transfer calculated from the cooling period. f Heating curve of HCu dispersed in water for five laser on/off cycles irradiated by 808 nm laser at the power intensity of 1.5 W/cm2