Graphene nanosheets-supported Ag nanoparticles for ultrasensitive detection of TNT by surface-enhanced Raman spectroscopy.

Sensitive and selective detection of 2,4,6-trinitrotoluene (TNT) has attracted considerable attention due to the wide applications of TNT as explosive material. Many efforts have been made to develop various sensors for detecting TNT in recent years. We herein report a novel sensor based on p-aminothiophenol (PATP) functionalized silver nanoparticles supported on graphene nanosheets (Ag/GNs), which was found to be a kind of effective chemosensor for the ultratrace detection of TNT by using surface enhanced Raman scattering (SERS). In the present hybrid material, PATP is paired together to form a corresponding azo compound p, p'-dimercaptoazobenzene (DMAB) and thus can be used as a model Raman probe. The π-donor-acceptor interaction between π-acceptor TNT and π-donor DMAB-Ag/GNs complex can effectively induce the "hot spots" for SERS. The intense spectral resonance from the DMAB-TNT-DMAB bridges formed between the Ag/GNs nanosheets could result in enhanced Raman signals of DMAB molecules with the presence of ultratrace TNT. SERS measurements demonstrated that TNT with concentration as low as 10(-11)M can be detected by using the present SERS platform. The present study not only provides a facile method for ultrasensitive and selective detection of TNT but also could develop a graphene-based SERS platform.