Graphene oxide encapsulated gold nanoparticle based stable fibre optic sucrose sensor

Abstract

Optical fibre based localized surface plasmon resonance (LSPR) sensor using graphene oxide (GO) encapsulated Au nanoparticles has been reported for sucrose sensing. Au-nanoparticles (AuNPs) are encapsulated with GO in fixed ratio to prevent the AuNPs from aggregation as agglomeration of AuNPs broadens the absorbance spectra by more than 25%. The TEM results support the formation of 2nm thickness of GO around Au nanoparticle of approximate size of 30nm thereby making the sensor stable. The GO encapsulated AuNPs was immobilized on the core of processed and functionalized optical fibre for sucrose sensing. We found that the peak absorbance changes with sucrose refractive index and the sensitivity of 2.288 ΔA/RIU has been obtained i.e. the peak absorbance changes by 75.78% with 0.0395 change in refractive index of sucrose. Our experimental results are in good agreement with theory.