Development of an optical fiber surface plasmon resonance sensor decorated with MoS2/AuNP plasmonic hybrid structure by using polydopamine-assisted electroless plating

A simple and low-cost fabrication method via polydopamine accelerated electroless plating (ELP) for an optical fiber surface plasmon resonance (SPR) sensor with molybdenum disulfide nanosheets (MoS 2 NSs) and gold nanoparticles (AuNPs) hybrid structure was proposed. The MoS 2 NSs were prepared by ultrasonic-assisted mixed-solvent liquid-phase exfoliation method. MoS 2 NSs and AuNPs were sequentially immobilized on the optical fiber by electrostatic interaction and Au-S bond supported by polydopamine and 1,2-ethanedithiol respectively, and a gold film supporting SPR was fabricated by ELP to form the optical fiber SPR sensor. The synthesized nanostructures and optical fiber sensors were characterized for their structural, morphological and optical properties. Some key experimental parameters, including dopamine concentration, dopamine polymerization temperature, dopamine polymerization time, pH of MoS 2 NSs solution and plating time, were investigated in detail. The refractive index sensitivity of sensor with the fiber/MoS 2 /AuNPs/Au structure achieved 678.85–7231.64 nm/RIU in the range of 1.3329–1.3638, which was approximately 52.35 % and 16.37 % higher than that of conventional sensors in the low refractive index range and high refractive index range respectively. This work proposed a facile, rapid and effective method to fabricate optical fiber SPR sensor to enhance its sensitivity, which indicates the potential application of the fabricated sensor in optical sensing field.