Effects Of Nitrogen-Dioxide On Surface-Plasmon Resonance Of Substituted Phthalocyanine Films

Surface plasmon resonance (SPR) of spun films of crown-ether-substituted phthalocyanines and octa-3,7,11-trimethyldodecyloxy phthalocyanine [H(2)pc(12.3)] shows changes on exposure of the films to nitrogen dioxide. The response and reversal rates of these effects parallel those of semiconductivity changes shown by the same materials. SPR is shown to provide additional information on the interaction between the gas and films as changes in both position and depth of the resonance are measurable. For the 15-crown-5-metal-free phthalocyanine, these effects are larger and more readily reversible in 50% relative humidity than in dry conditions, and are readily measurable even in NO2 concentrations as low as 1 ppm. A simple convergent-beam configuration is suggested for a practical NO2 sensor using SPR principles.