Graphene-enhanced surface plasmon resonance in photonic crystal fiber for sensing glucose in serum

Abstract

This study presents a solid-core photonic crystal fibre (PCF) with a metallic nanolayer of gold (Au)/silver (Ag) and graphene on the outer surface for glucose sensing applications. Graphene nanoparticles were prepared by pulsed laser ablation in liquid (PLAL) and then mixed with a polyvinyl alcohol (PVA) solution to coat the PCF surface. Glucose solutions with a refractive index (RI) ranging from 1.3475 to 1.3502 were used for evaluation. Results exhibit that the PCF sensor's sensitivity is significantly improved by incorporating a graphene layer onto the Au/Ag nanofilm coatings. The maximum sensitivity achieved for glucose detection in blood was 4284.243 nm/RIU and 3775 nm/RIU, with corresponding resolutions of 1×10-5 and 1.5×10-5 for graphene on Au and Ag, respectively. Experimental values yielded sensitivities of 1314 nm/RIU and 1119 nm/RIU, with resolutions of 2.5×10-5 and 2.7×10-5 for graphene on Au and Ag, respectively. Nanomaterials were investigated using a multi-technique approach encompassing transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and UV-VIS spectroscopy. TEM provided nanoscale visualization, revealing size, shape, and distribution characteristics. FTIR spectroscopy identified functional groups and bonding features, sp2 C-C bond stretching between 1580 and 1450 cm-1. Raman spectroscopy assessed structural integrity via D and G bands at 1350 cm-1 and 1590 cm-1. UV-vis spectroscopy elucidated optical properties. Integrating metallic Au/Ag and graphene layers on the PCF exterior shows excellent potential for developing susceptible bio-chemical detection devices.