Vacuum-tuned-atmosphere induced assembly of Au@Ag core/shell nanocubes into multi-dimensional superstructures and the ultrasensitive IAPP proteins SERS detection

Utilizing vacuum-tuned-atmosphere induced dip coating method, we achieve the cross-dimensional macroscopic diverse self-assemblies by using one building block with one chemical functionality. Coordinated modulating the vacuum degree, colloid concentration and evaporation atmosphere, Au@Ag core/shell NCs can controllably assemble into diverse multi-dimensional superstructures. Under 0.08 MPa, we obtained the two-dimensional (2D) stepped superstructures with continuously tunable step width. In addition, we generated a series of tailorable nanoscale-roughened 2D Au@Ag NCs superstructures at 0.04 MPa, which exhibited the label-free ultrasensitive SERS detection for the different mutants of IAPP8-37 proteins. Under 0.01 MPa, we obtained the cross-dimensional tailorable Au@Ag NCs assemblies from random to macroscale 2D and three-dimensional (3D) densest superstructures by adjusting the capping ligand-environmental molecule interactions. This is a flexible method to generate as-prepared Au@Ag core/shell NCs into well-defined macroscopic diverse superstructures and to promote the exploitation into biological applications.