Highly sensitive vapor detection of amines with fluorescent conjugated polymer: A novel lasing turn-on sensory mechanism

A novel lasing “turn-on” sensory mechanism for highly sensitive vapor detection of amines is developed, utilizing a polyfluorene/palladium tetraphenylporphyrin (PFO/PdTPP) composite film as the sensing medium. A rational ratio of PdTPP could effectively quench the fluorescence of PFO via electron/energy-transfer, and the reversed electron/energy-transfer brought on fluorescence recovery once electron donating amine binding with PdTPP, which resulted in a “turn-on” lasing action under optical pump. The lasing “turn-on” action shows sensitivity more than 5 times higher compared with the spontaneous emission (fluorescence) detection. Various amines have different binding intensity with PdTPP as well as diverse fluorescence recovery features brought on the distinction of lasing thresholds and the selectivity of sensing amines. From the theoretical analysis, we could come to a conclusion that the threshold characteristic of lasing action leads to the excellent amplification of sensitivity and selectivity. The novel “turn-on” lasing sensory mechanism could be extended to other “turn-on” fluorescent sensory systems in case the used sensory materials show favorable gain features for lasing.