Reliable molecular trace-detection based on flexible SERS substrate of graphene/Ag-nanoflowers/PMMA

• Published in: Sensors and actuators. B, Chemical Vol. 249; pp. 439 - 450
• Main Authors: Qiu, Hengwei, Wang, Minqiang, Jiang, Shouzhen, Zhang, Lin, Yang, Zhi, Li, Le, Li, Junjie, Cao, Minghui, Huang, Jin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2017
• Subjects: Ag-nanoflowers; Flexible SERS substrate; Molecular detection; Molecular detection; Flexible SERS substrate; Ag-nanoflowers
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2017.04.118

•First, the G/AgNFs/PMMA flexible substrate was fabricated by using a facilegraphene templated electroreduction method.•Second, the detection limit for R6G in-situ detectionby covering the G/AgNFs/PMMA flexible substrate can reach 10−14M.•Third, the G/AgNFs/PMMA flexible substrate can be used on real-world objects with any arbitrary morphology. Flexible substrate consisted of PMMA-supported monolayer graphene with sandwiched Ag-nanoflowers (G/AgNFs/PMMA) for ultrasensitive, reproducible, and stable surface-enhanced Raman scattering (SERS) detection is reported. Graphene templated micro-current-assisted chemical reduction method was employed to support AgNFs growth, and uniform-distribution AgNFs with all directions nanotips can generate tremendous enhancement factor and intensive hotspots. The minimum detectable concentration (i.e., detection limit) for rhodamine 6G (R6G) in-situ detection by covering this as-synthesized G/AgNFs/PMMA flexible substrate can be as low as 10−14M. Moreover, graphene can effectively stabilize the SERS signals and protect AgNFs from oxidation, endowing this flexible substrate a long-term stability with maximum intensity deviation lower than 10%, for the quantitative measurements from spot-to-spot or substrate-to-substrate. In order to trial its practical applications with various real-world surfaces, the in-situ SERS detection of phenylalanine@apple, adenosine aqueous solution and methylene-blue@fish was performed by covering this G/AgNFs/PMMA flexible substrate. Clear Raman peaks can be obtained for all the selected samples with concentration of 10−10M and, importantly, good linear relationship between Raman intensity and molecular concentration indicates the potential application of the G/AgNFs/PMMA flexible substrate in quantitative determination. Thus, this high-efficiency and low-cost flexible SERS substrate may provide a new way for the molecular trace-detection in food security and environmental protection.