Synergistic upconversion photodynamic and photothermal therapy under cold near-infrared excitation

Lanthanide-doped upconversion nanoparticles (UCNPs) have been extensively investigated due to their unique capabilities of upconverting near-infrared light (NIR) to visible/ultraviolet emission. However, use of conventional Yb-based UCNPs under 980 nm excitation for biomedical applications is limited due to the overheating caused by the strong light absorption by water at this wavelength. Although this could be improved by using Nd3+-Yb3+...