Gold nanoparticles (AuNPs) and graphene oxide heterostructures with gold film coupling for an enhanced sensitivity surface plasmon resonance (SPR) fiber sensor

Scholars in the field of surface plasmon resonance (SPR) sensors have long been devoted into tackling the question of improving sensitivity while maintaining high-level stability and re-usability. Presented in this paper is a highly sensible SPR fiber sensor established on gold nanoparticle (AuNPs)/graphene oxide (GO) heterostructures and Au film coupling enhancement. The local electric field enhancement of the gold nanoparticle/graphene oxide heterostructure and gold film coupling, together with the sensitivity of the sensor, was analyzed using a finite element method. Theoretical results have provided evidence that this structure is efficient in enhancing the surface plasmon polariton (SPP) coupling, the local electric field, and the depth of electric field propagation outwards, while significantly improving the sensitivity of the sensor. Sensors with single- and double-layer gold nanoparticle/graphene oxide and enhanced Au film coupling were prepared with refractive index (RI) sensitivities of 2899.4 nm/RIU and 3436.2 nm/RIU, respectively, 37.92% and 63.46% higher than for conventional gold film sensors. Due to the chemical bonding of graphene oxide, the materials on the sensor have shown considerably robust interconnections, and the performance of the sensor remains almost unaffected after many measurements. Promising stability and reusability have been demonstrated, presenting favorable prospects for practical applications.