Highly Sensitive Surface Enhanced Raman Spectroscopy from Ag Nanoparticles Decorated Graphene Sheet

Yuan Wu,Xiaoli Wang,Xin Li,Hongzhong Liu,Weihua Liu,Sweejiang Yoo,Hui Song

doi:10.1155/2014/538024

Abstract

Surface enhanced Raman spectroscopy (SERS) is a powerful analytical technique and has been most intensively studied. In this work, electroless deposition is proposed for Ag nanoparticles (NPs) decorated on chemical vapor deposition (CVD) growth graphene sheets (GS) to create hybrid SERS substrate. From three aspects of size distribution, morphology, and coverage, Ag NPs controllable decoration on GS and SERS enhancement factors of the hybrid SERS substrate is investigated. 200–300 times enhanced SERS intensities are detected from the Ag NPs on GS hybrid as compared to pure GS. Controllable decoration is crucial for improving SERS enhancement factorsβEF, becauseβEFfrom quasi cubic Ag NPs on GS is 6.53 times stronger than that from spheric one; 1.6 timesβEFis detected while the Ag NPs size distribution is reduced to half, and when the coverage is doubled,βEFis nearly doubled. This controllable Ag NPs/GS hybrid is capable of serving as a high performance SERS substrate for efficient chemical and biological sensing applications.

Highlights

Due to its high sensitivity, low background fluorescence noise, capability of single molecular recognition, and nondestructive testing of samples, surface enhanced Raman scattering (SERS) technique, as an important detection technology, is widely applied in chemical sensing [1,2,3], photonics [4], catalysis [5], ultrasensitive biosensors [6, 7], and many other areas [8, 9]
Controllable decoration preparation is crucial for improving SERS enhancement factors βEF, since the quasi cubic Ag NPs on graphene sheets (GS) SERS enhancement factors βEF are 6.53 times in average value stronger than that of spheric one
By taking advantage of both traditional metallic substrate and graphene substrates, we successfully decorated Ag NPs on chemical vapor deposition (CVD) growth GS where size distribution, morphology, and coverage of Ag NPs could be conveniently controlled by carefully manipulating the electroless deposition conditions

Summary

Introduction

Due to its high sensitivity, low background fluorescence noise, capability of single molecular recognition, and nondestructive testing of samples, surface enhanced Raman scattering (SERS) technique, as an important detection technology, is widely applied in chemical sensing [1,2,3], photonics [4], catalysis [5], ultrasensitive biosensors [6, 7], and many other areas [8, 9]. Rough-surface treatment for metal electrode and noble metal sol nanoparticles (NPs) are commonly used in SERS substrate process [5, 12,13,14,15], because SERS βEF depends largely on the type and morphology of the metal These approaches cannot accurately control the roughness and uniformity of the SERS substrate or the size distribution, morphology, and coverage of the metal NPs and result in consequent unstable and no reproducible SERS analysis and lower βEF. We try to study the controllable decoration and SERS βEF of the hybrid substrate from three aspects as Ag NPs size distribution, morphology, and coverage on GS

Materials and Experimental Section

Results and Discussion

Conclusion