A fiber-optic localized surface plasmon resonance (LSPR) sensor anchored with metal organic framework (HKUST-1) film for acetone sensing

摘要

A tip-based fiber-optic localized surface plasmon resonance (LSPR) sensor is reported for sensing of acetone. It is designed by coating the tip of multi-mode optical fiber with gold nanoparticles (size: ～40 nm) via a chemisorption process and further functionalization with a metal-organic framework (MOF) HKUST-1 via a layer-by-layer process. Two sensors with a different number of layers (80 and 120) corresponding to different thicknesses are reported. Both sensors show a redshift of resonance wavelength to acetone as a result of an increase in local refractive index induced by acetone adsorption into the HKUST-1 thin film. Sensors gradually saturate as acetone concentration increases and are fully reversible when the concentration decreases. The sensor with a thicker film exhibits slightly higher sensitivity to acetone than the thinner film with a wavelength shift of 5.27 nm for the concentration of 3.4 %.