Layer-by-layer reduced graphene oxide (rGO)/gold nanosheets (AuNSs) hybrid films: significantly enhanced photothermal transition effect compared with rGO or AuNSs films

Photothermal materials prepared from graphene and Au nanoparticles have received increasing attentions in various fields ranging from smart devices to advanced medical therapies. In this report, we studied the photothermal transition effects of LbL AuNS/rGO (AuNS: Au nanosheets) films under laser irradiation at 940 nm and comparisons were made with the film of rGO or AuNSs, wherein a single type of photothermal effective species exists. The results indicate that the hybrid LbL AuNS/rGO films displayed enhanced photothermal effects compared with the rGO or AuNSs films. The photothermal performance of the hybrid AuNS/rGO films deteriorated over repeated use or long-term laser irradiation, but the ultimate performance after irradiation was still better than that of the rGO or AuNS films. The hybrid film was able to load the model drug methylene blue (MB), and release MB 4 times faster with NIR irradiation than without, suggesting potential application in the combined chemical and thermal therapies. Thus, the hybrid film of AuNS/rGO is recommended when short-term or few-cycle photothermal applications are required. In comparison, rGO multilayered film better suits long-term or repeated photothermal applications, wherein stable photothermal performance is required.