Gold nanocages for effective photothermal conversion and related applications

Abstract

Gold nanocages (AuNCs) are a class of hollow nanocrystals with ultrathin and porous walls made of Au or Au-based alloys. When interacting with light, AuNCs exhibit a large absorption cross section and a high efficiency for light-to-heat conversion, making them effective photothermal transducers. Significantly, their absorption peak can be easily and precisely tuned through the visible and near-infrared regions to optimize their interaction with light of different wavelengths. As an inorganic nanomaterial, AuNCs have much better photo-stability compared to conventional organic dyes. This perspective summarizes recent progress in controlling the synthesis of AuNCs, together with their use in applications involving photothermal conversion. In the synthesis part, we pay particular attention to the strategies developed for tuning their size, shape, and composition, as well as the thickness and porosity of the walls. We then discuss the photothermal properties of AuNCs in terms of both theoretical calculations and experimental measurements, followed by a number of examples to highlight their applications in the context of light detection, water evaporation, phase transition, controlled release, and photothermal therapy. At the end, we offer some perspectives on the challenges and opportunities with respect to both the synthesis and application of AuNCs.