Photoheating Effects of CuS@PEI_GQDs Nanoshells under Near-Infrared Laser and Sunlight Irradiation

CuS nanoparticles (CuS NPs) have excellent photothermal conversion effects due to their strong and wide-band light absorption. The composite of CuS NPs may enhance the light absorption and photoheating effect, and their broad applications have appealed to wide interests. In this paper, ethylene imine polymer (PEI)-linked graphene quantum dots (PEI_GQDs) were easily obtained by an ultrasonic-assisted hydrothermal approach, and CuS nanoshells (NSs) were prepared with Cu2O NSs as a template. The composite of CuS@PEI_GQDs NSs was easily obtained by self-assembly due to the electrostatic attraction between PEI_GQDs and CuS NSs. The morphology, structure, surface chemistry, and optical absorption of the prepared nanomaterials were characterized by multi-microscopic techniques. The results of high-resolution transmission electron microscope (HRTEM), X-ray diffractometer (XRD), Fourier transform infrared (FTIR), X-ray photoelectronic spectroscopy (XPS), and energy-dispersive spectrum (EDS) show that the PEI_GQDs were successfully linked on the surfaces of the CuS NSs; the FTIR analysis reveals that there is an interaction between CuS NSs and PEI_GQDs by chelation between Cu2+ and −NH2 in PEI_GQDs. The pore size distribution indicated that both the CuS NSs and CuS@PEI_GQDs NSs contained mesopores in the wall shells. The CuS@PEI_GQDs NSs displayed enhanced absorption within 190–500 and 630–1100 nm compared to the CuS NSs. The photoheating effects of CuS@PEI_GQDs NSs and CuS NSs were investigated under 808 nm laser and sunlight irradiation, and CuS@PEI_GQDs NSs presented a better photoheating effect and photothermal stability than CuS NSs. Our results provide a facile approach to fabricate other GQD-coated nanomaterials. The excellent photoheating effects of CuS@PEI_GQDs NSs are promising in photothermal conversion.