Colloidal-ALD-Grown Hybrid Shells Nucleate via a Ligand-Precursor Complex

Area of Science:

• Nanotechnology
• Materials Science
• Surface Chemistry

Background:

• Colloidal atomic layer deposition (c-ALD) creates hybrid organic-inorganic oxide shells on nanoparticles.
• This method improves nanoparticle stability and dispersion, vital for applications.
• The formation mechanism and interface complexities of c-ALD shells remain unclear.

Purpose of the Study:

• To elucidate the mechanism of inorganic shell formation in c-ALD.
• To identify the role of organic ligands in synthesizing core-shell nanostructures.
• To understand the interfacial interactions during c-ALD.

Main Methods:

• Dynamic nuclear polarization surface-enhanced nuclear magnetic resonance spectroscopy (DNP SENS).
• Density functional theory (DFT) structure calculations.
• Synthesis of ligand-functionalized inorganic nanoparticles and c-ALD shell growth.

Main Results:

• Carboxylate ligands are identified as essential for c-ALD shell synthesis.
• A ligand-precursor complex forms between the aluminum precursor and the NP surface.
• This complex serves as the nucleation site for shell growth.

Conclusions:

• Carboxylate ligands mediate the interaction between precursors and nanoparticle surfaces.
• The ligand-precursor complex is the initiating step for c-ALD shell formation.
• Understanding this mechanism advances the application of c-ALD for stable nanomaterials.