Dual-Mode Visual Detection of Ammonia Based on the Vapochromism of a Fluorinated Pentamethine Cyanine Dye Doped in Silicone Films

Abstract A novel ring-fluorinated pentamethine cyanine dye was synthesized. Fluorination induced hypsochromic shifts and enhanced fluorescence quantum yields by suppressing non-radiative deactivation. A silicone film doped with the dye showed rapid color changes and fluorescence quenching upon ammonia exposure. This reversible response enables the intuitive visual detection of toxic ammonia, potentially contributing to safe use of ammonia as a next-generation fuel.