UiO-66@Allylthiourea film coated optical fiber cadmium ion sensor with spiral grating temperature compensator

In this article, we proposed a gold film-coated spiral fiber grating (SFG) sensor, which can simultaneously generate surface plasmon resonance (SPR) spectra and grating spectra. A layer of UiO-66@allylthiourea composite film has grown on the surface of the gold film to be used for the specific detection of cadmium ions (Cd2+). The allylthiourea group exhibits a specific binding affinity to Cd2+, and the UiO-66 can provide a filling skeleton to increase the specific surface area of ion adsorption. When Cd2+ is adsorbed by the composite film, the equivalent refractive index (RI) of the film changes accordingly, leading to a phase change of the SPR spectra and the grating spectra. In addition, the dual parameter matrix can simultaneously demodulate ion concentration changes and environmental temperature. The experimental results show that the Cd2+ sensitivity of the sensor can reach 0.349 nm/nM, and the temperature sensitivity can reach 0.323 nm/celcius. This sensor has the potential for development in high-precision ion detection.