Gram-Scale Synthesis of Isolated Monodisperse Gold Nanorods

Area of Science:

• Nanotechnology
• Materials Science
• Plasmonics

Background:

• Scalable synthesis of gold nanorods (AuNRs) in gram quantities remains a significant challenge.
• Existing methods yield milligram quantities with limited gold conversion and difficult surface modification.
• Cetyltrimethylammonium bromide (CTAB) coating hinders further functionalization of AuNRs.

Purpose of the Study:

• To develop a method for large-scale, gram-quantity synthesis of monodisperse and functionalized AuNRs.
• To overcome limitations of CTAB removal and enable subsequent chemical modification.
• To produce AuNRs suitable for advanced applications in nanotechnology, plasmonics, and sensing.

Main Methods:

• Increased precursor concentration (HAuCl₄) and controlled ascorbic acid addition for enhanced AuNR growth and reduced impurities.
• Utilized a ligand-exchange strategy to replace CTAB with 4-mercaptophenol, introducing functional hydroxyl groups.
• Employed tetrahydrofuran (THF) for ligand exchange and purification via dispersion, rinsing, and centrifugation.

Main Results:

• Achieved gram-scale synthesis of monodisperse AuNRs with a narrow size distribution (σ≈5%).
• Successfully replaced CTAB with 4-mercaptophenol, yielding functionalized AuNRs with available hydroxyl groups.
• Demonstrated a robust method for AuNRs isolation and purification suitable for further chemical coupling.

Conclusions:

• The developed method enables gram-scale production of high-quality, functionalized AuNRs.
• This advancement facilitates the use of AuNRs in diverse nanotechnology and sensing applications.
• The ligand-exchange approach provides versatile functionalization for tailored material properties.