Fluorinated Anionic Metal–Organic Frameworks for Dual-Mode Electrochemical/Photoelectrochemical Dopamine Detection

Abstract

Fluorinated anionic metal-organic frameworks (MOFs) have emerged as compelling sensing platforms owing to their tailorable structural diversity and unique electronic characteristics. In this study, we developed a novel fluorinated anionic MOF, (Me₂NH₂)[Er^III(tcbpe-F)DMF]•3DMF•4.5H₂O (YNU-101, tcbpe-F = 4',4‴,4⁗',4″'''''-(ethene-1,1,2,2-tetrayl)tetrakis(3-fluoro-[1,1'-biphenyl]-4-carboxylic acid), DMF = N,N-dimethylformamide), through a one-step solvothermal method. The YNU-101 was successfully developed as a dual-mode electrochemical (EC) and photoelectrochemical (PEC) sensor for the detection of dopamine (DA). As an EC sensor, it exhibited an exceptionally low detection limit of 17.6 nM, while the PEC counterpart demonstrated an expanded detection range of 0.5-700 μM. The complementary advantages of the dual-mode approach were validated through practical applications in bovine serum samples. Density functional theory calculations further elucidated the high selectivity mechanisms of YNU-101 for both EC and PEC sensing of DA. This work not only deepens our understanding of electrochemical and photoelectrochemical properties of fluorinated anionic MOFs but also paves the way for the development of dual-mode DA sensors. By establishing a systematic strategy for such sensor fabrication, it provides promising directions for advancing next-generation smart sensing devices.