SUBSTITUTED PHTHALOCYANINE GAS SENSORS

Gas sensors are playing an increasingly important role in the monitori ng of workplace environments. Sublimed films of metal phthalocyanines have been successfully used as NO2 sensors, but do suffer certain limi tations. Langmuir-Blodgett films of many substituted phthalocyanines h ave proved difficult to prepare reproducibly. An asymmetrically substi tuted phthalocyanine, 1,4-bis(4-hydroxybutyl) 8,11,15,18,22,25-hexaoct ylphthalocyanine, designed specifically to form good-quality Langmuir- Blodgett films, has been successfully deposited. Prepared devices show a useful room-temperature response to NO2. The reproducibility, lifet ime, shelflife, specificity and effects of water vapour on these devic es have been investigated.