Green synthesis of silver nanoparticle-reduced graphene oxide using Psidium guajava and its application in SERS for the detection of methylene blue

• Published in: Applied surface science 2017-06, Vol.406, p.312-318
• Main Authors: Chettri, Prajwal, Vendamani, V.S., Tripathi, Ajay, Singh, Manish Kumar, Pathak, Anand P., Tiwari, Archana
• Format: Article
• Language: English
• Subjects: Charge transfer; Fluorescence quenching; Methylene blue; Psidium guajava; SERS; Silver nanoparticle-reduced graphene oxide
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2017.02.073

•Psidium guajava extract simultaneously reduces AgNO3 and graphene oxide.•The reduction yields Ag nanoparticle-reduced graphene oxide composite.•The composite exhibits remarkable enhancement of the Raman signal of the dye.•The reduce graphene oxide shows better PL quenching ability than the composite.•The PL quenching behaviour is ascribed to the charge transfer processes. Here we present the synthesis of reduced graphene oxide and silver nanoparticle-reduced graphene oxide composites using aqueous extract of dry leaves of Psidium guajava by one pot reflux method. Psidium guajava extract simultaneously reduces silver nitrate and graphene oxide in the reaction mixture which is confirmed by various spectroscopic techniques. Variable concentrations of silver nitrate solution are used to obtain reduced graphene oxide with different dosage of silver nanoparticles and the resultant composites are examined using surface enhanced Raman scattering measurements. Considering methylene blue as a probe molecule, it is found that the surface enhanced Raman scattering activity increases with the increase in the dose of silver nanoparticles. Our as-synthesised silver nanoparticle-reduced graphene oxide composite shows remarkable performance in detecting methylene blue with concentration as low as 10−8M for which the enhancement factor is 4.6×105. In addition, we report that the reduced graphene oxide quenches the photoluminescence of methylene blue more efficiently than silver nanoparticle-reduced graphene oxide composite. The charge transfer states have been extracted which are mainly responsible for the quenching processes.