Photoelectron-transfer-effect grafting: Validation of a generalized strategy for fluorescence and photoelectrochemical dual-mode detection of hydrogen sulfide.

The progress of modern research is constantly fueled by the convergence of multiple technologies. Despite the enormous potential of both fluorescence (FL) and photoelectrochemical (PEC) technologies, the development of synergistic PEC-FL sensing platforms that combine the advantages of both is still in its early stages due to their relatively recent inception. Hydrogen sulfide (H 2 S), possessing dual irritant and asphyxiating traits, poses challenges for environmental preservation and human health. The development of the PEC-FL detection methodology for H 2 S in complex environmental settings is imperative. Combining FL and PEC sensing techniques, this work presented a new concept of photoinduced electron-transfer (PET) effect grafting for dual-mode fluorescence and PEC analysis. Briefly, a well-designed fluorescent molecule (BTFM-DNP) featuring the PET effect was synthesized and implemented to modulate the photoelectric response of the indium tin oxide (ITO)/BiOI photocathode electrode. After reacting with H 2 S, the thiolysis of dinitrophenyl ether eliminated the intramolecular PET effect and recovered the significant fluorescence of the probe. Remarkably, the newly formed 2,4-dinitrobenzenethiol (DBT) with strong electron-withdrawing groups was then grafted to the ITO/BiOI photoelectrode and achieved the successful transfer of the PET process, resulting in a sharp decrease in photocurrent. The as-developed dual-mode protocol exhibited good performance in terms of ultra-sensitivity, high selectivity, fast response, and a wide detection range from 1 pM to 80 μM. The newly developed PEC-FL sensing platform can be applied to detect H 2 S levels in both the environment and food. This study demonstrates a promising synergy between fluorescent probes and PEC sensors, offering a novel perspective on the advancement of multi-mode analysis techniques. This approach has the potential to significantly enhance detection accuracy and reliability. [Display omitted] • A dual-mode strategy was proposed for H 2 S-sensitive detection. • The PET effect was grafted into an innovative fusion of fluorescence and PEC. • Dual-mode analysis showed ultra-sensitivity and a wide detection range. [ABSTRACT FROM AUTHOR]