LUMINESCENCE LIFETIME-BASED SENSOR FOR RELATIVE AIR HUMIDITY

The development of new sensitive coatings for fibre-optic sensors that utilize the Langmuir-Blodgett technique is described. Monomolecular t hin solid films containing phosphorescent water-soluble Pt- and Pd-por phyrins and amphiphilic surface-active polymer have been prepared by a n original method and transferred onto solid supports. The solid-state coatings thus obtained show intense long-decay phosphorescence in amb ient air, which is found to be sensitive to the water content in the e nvironment, i.e., the relative humidity (RH) of air. The coatings have been studied by optical methods with emphasis on luminescence quenchi ng and lifetime measurements. The results are applied to luminescence lifetime-based sensing of RH and a corresponding fibre-optic prototype device has been created.