Increasing gold nanostars SERS response with silver shells: a surface-based seed-growth approach

Area of Science:

• Nanotechnology
• Spectroscopy
• Materials Science

Background:

• Surface-enhanced Raman spectroscopy (SERS) is a powerful analytical technique.
• Developing sensitive and reproducible SERS substrates is crucial for various applications.
• Gold nanostars (GNS) offer unique plasmonic properties suitable for SERS.

Purpose of the Study:

• To introduce a straightforward method for preparing GNS@Ag SERS chips.
• To optimize the preparation of GNS@Ag chips for enhanced SERS signals.
• To evaluate the performance of GNS@Ag chips for pesticide detection.

Main Methods:

• A seed growth method was employed directly on a glass surface using GNS as seeds.
• A green synthesis pathway using silver nitrate, ascorbic acid, and water was utilized for silver shell growth.
• Optimization of the preparation process to maximize SERS signals.

Main Results:

• A monolayer of silver-coated gold nanostars (GNS@Ag) was successfully grafted onto a glass surface.
• The GNS@Ag SERS chips exhibited SERS response one order of magnitude greater than GNS-based chips.
• The chips demonstrated good homogeneity and acceptable reproducibility.
• The GNS@Ag SERS chips achieved detection of the pesticide thiram down to 20 ppb.

Conclusions:

• A facile and green method for fabricating high-performance GNS@Ag SERS chips was established.
• The developed SERS chips show significant signal enhancement and potential for sensitive environmental monitoring.
• The GNS@Ag SERS chips are effective for the trace detection of pesticides like thiram.