A novel amphiphilic zinc phthalocyanine LB flms as gas sensor material andits interaction with NH3

Two kinds of amphiphilic phthalocyanines(AmPc,AmPcZn) have been deposited a s smooth and well ordered LB films. Absorption spectra show that AmPc mms a re consistent with a stacked cofacial columnar structure while the AmPcZn f ilms consist of aggregates with weakly interacting molecules. These two fil ms exhibit different behavior toward NH3 gas-sensing. AmPcZn films gave str ong and fast response on exposure to NH3 whereas AmPc films showed very wea k response. It is proposed that coordination of NH3 by AmPcZn results in lo wering the energy gap and hence the activation energy of AmpcZn that accoun t for the larger increase in conductance of AmpcZn films compared with AmPc films.