# SERS Substrate Fabrication via Rapid Triboelectrification‐Driven Self‐Assembly of Close‐Packed Colloidal Monolayers

## TL;DR

A new method uses triboelectrification to quickly create high-performance SERS substrates for detecting trace chemicals.

## Contribution

A rapid, cost-effective method for fabricating SERS substrates using triboelectrification-driven self-assembly is introduced.

## Key findings

- Self-assembled 500 nm particles with 50–65 nm Au coating achieved an enhancement factor of 1 × 10⁶.
- The method produced substrates with a detection limit 20–24 times lower than commercial alternatives.
- The process enables efficient and homogeneous monolayer production for scalable SERS applications.

## Abstract

Surface‐enhanced Raman spectroscopy (SERS) amplifies Raman signals on nanostructured metallic surfaces, enabling the detection of trace analytes. There has been a spur on the precise fabrication of conventional planar SERS substrates with high performance and reproducibility. Common methods, such as ion beam and colloidal lithography, provide high‐quality substrates but are often limited by high costs, complex processes, and challenges associated with mass manufacturing. Triboelectrification‐driven self‐assembly of dry colloidal powder offers a promising dry approach to attain ordered monolayer colloidal particles in <20 s rapidly. Here, we use this approach to produce high‐performance SERS substrates with reproducible signals. By optimizing particle size and gold coating thickness, we found that self‐assembled 500 nm particles with a 50 and 65 nm Au layer achieved a maximum enhancement factor (EF) of 1 × 10, and limit of detection (LOD) of 33–36 nM, in our initial characterization study without coordinate translation. Compared with commercial substrates (Silmeco; Hamamatsu) under matched conditions, this corresponds to 20–24 × lower LOD (33–36 nM vs. 680–800 nM) and 10–100 × higher maximum EF. These results highlight triboelectrification's ability to efficiently and cost‐effectively produce homogeneous monolayers, offering a promising alternative to more complex or expensive methods and unlocking the opportunity for large‐scale SERS substrate production with biosensing, diagnostics, and chemical detection applications.

Triboelectrification‐driven self‐assembly of dry colloidal powder offers a promising dry approach to rapidly (<20 s) attain ordered monolayer colloidal particles for surface‐enhanced Raman spectroscopy applications.