Highly Efficient Dual-Color Luminophores for Sensitive and Selective Detection of Diclazepam Based on MOF/COF Bi-Mesoporous Composites

Currently, studies on electrochemiluminescence (ECL)mainly focusedon the single emission of luminophores while those on multi-colorECL were rarely reported. Here, a bi-mesoporous composite of the metal-organicframework (MOF)/covalent-organic framework (COF) with strong and stabledual-color ECL was prepared to construct a novel ECL sensor for sensitivedetecting targets. A PTCA-COF with excellent ECL performance was loadedwith a great amount of another ECL emitter Cu-3(HHTP)(2). Remarkably, the integrated composite had both ECL propertiesof PTCA-COF at 520 nm and Cu-3(HHTP)(2) at 600nm wavelengths. Furthermore, Cu-3(HHTP)(2) withgood electron transfer ability can greatly enhance the electricalconductivity and promote electrochemical activation. Thus, the simultaneousenhanced two-color ECL intensity and the catalytic properties of theconductive MOF exerted a dual enhancement effect on the ECL signalof the composite. Significantly, diclazepam can not only be adsorbedwell on the multi-stage porous structure MOF/COF composite by & pi;-& pi;interactions but also selectively quench the ECL signal of the PTCA-COF,realizing the sensitive detection. The ECL sensor showed a wide detectionrange from 1.0 x 10(-13) to 1.0 x 10(-8) g/L, and the limit of detection (LOD) was as lowas 2.6 x 10(-14) g/L (S/N = 3). The proposedECL sensor preparation method was simple and sensitive, providinga new perspective for the potential application of multi-color ECLin the sensing field.