Fig. 2
A UV-vis-NIR absorption spectra of Au@Cu2-xSe aqueous suspensions. B Photothermal curves and C corresponding thermal photographs of Au@Cu2-xSe aqueous suspensions with different concentrations under NIR irradiation. D Heating-cooling curves of Au@Cu2-xSe aqueous suspension (50 µg mL−1) and pure water irradiated with NIR for 15 min and then naturally cooled to room temperature. E The calculation of time constant (τs) for the heat transfer from system obtained by applying the linear time data from the cooling period versus the negative natural logarithm of driving force temperature (θ). F Photothermal stability curve of Au@Cu2-xSe aqueous suspension (50 µg mL−1). The power density of 808 nm NIR was maintained at 1.0 W cm−2 in these photothermal tests