A fluorescence probe for highly selective and sensitive detection of gaseous ozone based on excited-state intramolecular proton transfer mechanism

Ozone is widely used in air sterilization, food and medical disinfection in modern society, but high ozone levels in the living environment are considered harmful and have been associated with various respiratory diseases. Therefore, quick detection for ozone of part per million (ppm) levels is significant for living environment and an excited-state intramolecular proton transfer (ESIPT) compound has been synthesized. Due to an intrinsic excited-state intramolecular proton transfer (ESIPT) process, this “off-on” probe can fluoresce in the solid-state. This intrinsic fluorescent property makes it easy to detect lower concentration of ozone since the reaction product of probe can avoid being affected by pH and solubility through luminescence in the solid-state. The limit of gaseous ozone detection can be as low as 0.28 ppm for obviously distinguishable fluorescence colour from blue to cyan, showing that the probe can be useful for detecting ozone without the need of elaborate equipment.