Fig. 1
a DLS of PYT NPs. Inset: their TEM image. b UV–Vis-NIR spectrum of PYT NPs. c Photothermal conversion of PYT NPs at different concentrations with 808 nm laser irradiation (1.0 W cm−2). d Photothermal images of PYT NPs at various concentrations (0, 10, 30, and 50 µg mL−1). e Photothermal stability during five heating–cooling cycles. f The PCE (η) calculation of PYT NPs