USE OF LUMINESCENT GOLD COMPOUNDS IN THE DESIGN OF THIN-FILM OXYGEN SENSORS

The use of two gold compounds incorporated into thin plastic films as luminescence quenching oxygen sensors is described. The films are sens itive both to gaseous oxygen and to oxygen dissolved in nonaqueous med ia such as ethanol. The luminescence quenching of these sensors by oxy gen obeys the Stern-Volmer equation and Stern-Volmer constants of 5.35 x 10(-3) and 0.9 x 10(-3) Torr(-1) are found, respectively, for the t wo dyes in a polystyrene polymer matrix. The sensitivity of the films is strongly influenced by the nature of the polymer matrix, and greate st sensitivity was found in systems based an the polymers polystyrene or cellulose acetate butyrate. Sensitivity was not found to be tempera ture dependent though raising the temperature hom 15 to 50 degrees C d id result in a slight decrease in emission intensity and a hypsochromi c shift in the emission wavelength. The rate of response and recovery of the sensors can be increased either by decreasing film thickness or by increasing the operating temperature. The operational and storage stability of these films is generally good though exposure to light sh ould be avoided as one of the dyes tends to undergo photobleaching pro bably due to a photoinduced ligand substitution reaction.