Fig. 3

Photothermal effects of rGO@Fe3O4. a Concentration-dependent temperature change of rGO@Fe₃O₄ solutions at different concentrations (0.0625, 0.125, 0.25, 0.5, and 1 mg mL⁻¹) under 808 nm irradiation at 2 W cm⁻² for 5 min. b Power-dependent temperature response of 0.25 mg mL⁻¹ rGO@Fe₃O₄ solution under the irradiation of an 808 nm NIR laser for 5 min (1 W cm⁻², 1.5 W cm⁻², 2 W cm⁻²). c Infrared thermal images of rGO@Fe₃O₄ solution at 0, 1, 2, 3, 4, and 5 min intervals stimulated at 808 nm (2 W cm⁻²). d Temperature increases of rGO@Fe₃O₄ (0.25 mg mL⁻¹) solution during 6 successive cycles of laser on/off under 808 nm irradiation at 2 W cm⁻²