Fabrication of Holey AuAgPt Nanosheets by Surface Doping-Mediated Oxidative Carving for Tunable Near-Infrared Absorption and Their Applications in Photothermal Conversion

Anisotropic noble metal nanocrystals with the ability of highly efficient photothermal conversion in the near-infrared (NIR) window is of great importance for the clinical application of photothermal therapy. Herein, we report a synthetic strategy to fabricate holey AuAgPt nanosheets that exhibit tunable absorptions between the NIR-I and NIR-II regions and promising use in photothermal conversion. In particular, the surface of Au nanosheets is primarily doped with Pt/Ag atoms, followed by the addition of HAuCl4 to create noncentered holes while retaining the edge parts. By creating in-plane holes via the oxidative carving, theoretical simulations confirm the formation of extensively polarized regions, and UV–vis extinction spectra show that the major absorption peak of AuAgPt holey nanosheets could be shifted from over 1100 nm toward 750 nm. The photothermal conversion efficiency of the optimized AuAgPt holey nanosheets are measured to be around 60 and 45%, respectively, under the laser irradiations at the wavelengths of 808 and 1064 nm, respectively, confirming their promising use in both NIR-I and NIR-II windows. The present study offers a feasible strategy to maneuver the optical properties of two-dimensional plasmonic nanomaterials with flexible and adjustable absorption centers within the NIR regions, shedding light on the rational design of highly efficient NIR photosensitizers.