Large-Area Gold-Coated Polyamide Nanopillar Arrays Consisting of Secondary Lamellar Structures and Sub-10-nm Gaps for Ultrasensitive SERS Detection

Abstract

Large-area gold-coated polyamide 66 (PA66) nanopillar (PA66NP@Au) arrays consisting of secondary lamellar structures and sub-10–nm gaps are fabricated for surface-enhanced Raman spectroscopy (SERS) using ultrathin anodized aluminum oxide (AAO) template, solution-phase growth of PA66 lamellae, and Au sputtering. Such closely packed PA66NP@Au arrays with high density of electromagnetic field enhancement (“hot spots”) on large area exhibit high SERS sensitivity for detection of rhodamine 6g (R6G) molecules with concentration down to 10−14 m and a large Raman analytical enhancement factor (AEF) of ≈1010. Furthermore, the as-fabricated PA66NP@Au arrays provide highly sensitive Raman signals in detection of a commonly pesticide residue, carbendazim with a limit of detection (LOD) of 0.05 mg L−1 (0.05 ppm), which is lower than that of maximum residue limit of 0.2 ppm allowed in Europe Union. The as-fabricated PA66NP@Au arrays are promising for highly sensitive and uniform SERS detection.