Organic Molecules as a Bridge Connecting Photoelectrochemistry and Fluorescence for Dual-Signal Assay

We report a strategy based on pyridyl-anchored organic small-molecule fluorescent probes to develop a dual-signal sensing platform. The strategy accomplishes an intelligent integration of fluorescence analysis with photoelectrochemical (PEC) sensing, thereby enabling rapid and precise detection of hypochlorite. In this work, the natural dye chromone was selected as the fluorophore for generating fluorescent signals. Meanwhile, by using phenothiazine (PTZ) as the specific recognition group and pyridine as the anchoring moiety, we designed and synthesized a novel organic small-molecule fluorescent probe. The obtained probe was used as a photosensitive material anchored to the TiO2 surface via N → Ti bonds, to form an FTO/TiO2/FPTZ-1 heterostructure-based dual-signal sensing platform for the detection of hypochlorite. This sensing platform has the characteristics of high specificity, sensitivity, and ease of preparation, enabling rapid qualitative fluorescence readout and quantitative photoelectrochemical readout of hypochlorite, with a limit of detection of 0.288 μM for fluorescence and 1.37 nM for PEC.