Shape-complementary co-assembly of concave nanocubes and nanospheres into binary superlattices

Area of Science:

• Nanotechnology
• Materials Science
• Surface Chemistry

Background:

• Controllable co-assembly of nanoparticles into binary superlattices (SLs) is crucial for tunable properties and multifunctionality.
• Developing efficient strategies for constructing binary SLs with controlled composition and structure remains a challenge.

Purpose of the Study:

• To report a facile and versatile shape-complementary co-assembly strategy for constructing tunable binary SLs.
• To explore the influence of particle size ratios on the resulting superlattice structures.
• To demonstrate the application of these binary SLs in surface-enhanced Raman scattering (SERS).

Main Methods:

• Co-assembly of concave gold nanocubes (cGNCs) and gold nanospheres (GNSs) utilizing shape complementarity.
• Varied the size ratios of GNSs and cGNCs to achieve different binary SL structures (NaCl-type, tetragonal, hexagonal).
• Co-assembly of cGNCs with PbS nanospheres, followed by selective etching to create checkerboard SLs.

Main Results:

• Highly ordered 2D and 3D GNS-cGNC binary SLs were successfully produced.
• Tunable structures (NaCl-type, tetragonal, hexagonal) were achieved by controlling particle size ratios.
• The GNS-cGNC binary SLs exhibited a high density of hot spots, leading to excellent SERS performance with a 10^-12 M detection limit for crystal violet.
• A binary PbS-Au SL was formed, and selective etching yielded a checkerboard SL of cGNCs.

Conclusions:

• The shape-complementary co-assembly strategy offers a facile and versatile approach for constructing tunable binary SLs.
• This method allows for precise control over SL structure and composition, paving the way for multicomponent SLs with tailored properties.
• The developed binary SLs demonstrate significant potential for applications in sensing, particularly in SERS.