▎ 摘　　要

We study the optical and photothermal properties of graphene coated gold-silver alloy hollow nanoshells (Au-Ag HNSs) using the effective medium theory combined with the Pennes bioheat and Arrhenius equations. To increase the stability of Au-Ag HNSs in the presence of oxidants, acid, and heating, we propose the use of graphene as a protective shell on Au-Ag HNSs in photothermal therapy (PTT) applications. Calculating the extinction efficiency in tumor tissue, we show that the surface plasmon resonant (SPR) peak of graphene coated Au-Ag HNSs can be easily adjusted within a wide range of biological windows by changing the inner radius, the Au-Ag shell thickness, and the alloy composition of Au-Ag. In addition, the effect of concentration of nanoparticles and the number of graphene layers on the temperature rise in the tumor tissue are investigated. To achieve a comprehensive study, the thermal damage in tumor tissue is also investigated and the region of tumor in which the irreversible thermal damage can occur is determined. Our results suggest that graphene coated Au-Ag HNSs can be used as an excellent class of nanoagents for PTT applications.