Coupling tandem MOFs in metal-insulator-metal resonator advanced chemo-sieving sensing

Metal-insulator-metal (MIM) resonator allows concentrating light into deep-subwavelength volumes for filtering by accessing surface plasmon polariton mode, which is typically constructed by using inorganic materials and polymers as an insulator. Although MIM filters can manipulate light, dynamic color change upon environmental stimuli is still challenging. Here, we report a metal-organic frameworks (MOFs) based MIM resonator with tunable bandwidth that can realize visualized sensing of chemicals. Different bandwidths of the resonator show distinct color reflection that can be tailored by different types of MOFs and thickness of the MOFs layers. Chemical sensing on the MOFs-based MIM resonators shows breakthrough enhancement of sensitivity. Moreover, we configure tandem MOFs thin films in the MIM to form a metal-insulator-insulator-metal (MIIM) resonator for promoting selective sensing of chemicals. Also, molecular dynamics simulations demonstrated that the MIIM resonator achieved selective adsorption of xylenes in a mixture of xylene and methanol due to the chemo-sieving effect. The MIIM resonators show not only host-guest chemistry and sieving performance of tandem MOFs with high durability, but also anti-interference selective sensing of analyte in the mixture.