GAS-DETECTION BY A MULTI-HYBRID SENSOR WITH DYE LANGMUIR-BLODGETT-FILMS DEPOSITED ON A QUARTZ OSCILLATOR

A hybrid gas sensor combined an optical detector with a weighing system for adsorbed gas is realized by dye LB-films deposited on a quartz oscillator. With this sensor, the change of fluorescence intensity from dye LB-film is simultaneously measured with the change of oscillation frequency of the quartz oscillator which depends on the amount of adsorbed gas in the LB-film. Squarylium dye LB-film and perylene dye LB-film were applied for this hybrid gas sensor. The quartz oscillators with LB-film commonly showed decrement of their oscillation frequency corresponding to the adsorption of gases. On the other hands, changes of fluorescence intensity depend on the type of gases, the dye molecules and its aggregation forms. These results suggest advantage of a multi-hybrid gas sensor using multiple quartz oscillators with different dye molecules. In this report, we discuss the responses of hybrid gas sensor in connection with the semiconductivity of the dye and its aggregate in LB-films.