Fig. 2
From: Recent advances in near-infrared-II hollow nanoplatforms for photothermal-based cancer treatment
a The schematic illustration of MCO NP synthesis; Transmission electron microscopy (TEM) and elemental mapping image of MCO-100 NPs (diameter was ~ 100 nm). Reproduced with permission from Ref. [132]. Copyright 2021, Royal Society of Chemistry. b Schematic illustration of Au–Ag HNP and Au–Ag@Au HNPs; Dark-field scanning TEM (DF-STEM) images and elemental mapping images of Au–Ag@Au HNPs. Reproduced with permission from Ref. [133]. Copyright 2015, American Chemical Society. c Schematic illustration of the formation process of HCONC; High-angle-annular-dark-field STEM (HAADF-STEM) and corresponding element mappings of single HCONC. Reproduced with permission from Ref. [134]. Copyright 2022, Wiley-VCH.