HUMIDITY DEPENDENCE OF PHOTOLUMINESCENCE IN COUMARIN-4-DOPED SOL-GEL COATING FILM

Coumarin 4 dye was doped in a silica matrix coated as a thin him by me ans of the sol-gel technique. The fluorescence intensity of the immobi lized dye was quenched by moisture. The humidity dependence of the flu orescence intensity was examined in the relative humidity range betwee n about 3 and 90% as a function of the concentration of coumarin 4 and catalytic aqueous HCl. The obtained results reveal that the fluoresce nces emitted from both the coumarin 4 monomer and the aggregates of dy e molecules are quenched by moisture and their quenching is explained by the Stern-Volmer equation.