Nonenzymatic Glucose Sensor Based on Au/ZnO Core–Shell Nanostructures\nDecorated with Au Nanoparticles and Enhanced with Blue and Green Light

Abstract

Au/ZnO core–shell nanostructures decorated with Au nanoparticles\nwere synthesized on an ITO/glass substrate. The investigated sensor\ncontains 2-D, 1-D, and 0-D nanostructures to provide a large surface-area-to-volume\nratio and catalytic quantum effect and to avoid the issues inherent\nin heterojunction interface barriers. The sensitivities of the fabricated\nglucose sensors in the dark and under blue and green LED illumination\nwere 3371.9, 4410.9, and 4157.8 μA/cm² mM^–1, respectively. The achieved sensitivities are higher than previous\nreports on Au nanostructure sensors by 2–100 times. Further,\nthe blue and green LED illumination respectively enhanced the sensitivity\nand CV glucose sensing currents by ∼30.8 and ∼23.3%\nand ∼27 and ∼35%. The detection limits of the glucose\nsensor in the dark and under visible illumination were the same at\n∼0.5 μM. Moreover, these visible light illumination enhancements\nare attributed to the localized surface plasmon resonance effect.