Interaction between copper tetra-4(2,4-ditert-amylphenoxy) phthalocyanine Langmuir-Blodgett films as a gas-sensitive sensor and NH3

Abstract Copper tetra-4-(2,4-di tert -amylphenoxy)phthalocyanine (tapCuPc) Langmuir-Blodgett (LB) films were deposited onto planar interdigital microelectrode arrays and the process of the interaction between the tapCuPc LB films and NH 3 was studied. The process of the interaction resulted in a large increase in the conductance of the LB film. The results of response and recovery processes were given when the tapCuPc LB films were exposed to 100 ppm NH 3 gas in air. It was suggested that the response process of the interaction between the tapCuPc LB films and NH 3 can be described by the relation I = I . 1−exp(− t / τ ), and the recovery process of the tapCuPc LB film may be described by the relation I = I exp(− t / τ 1 ). The two relations are in approximate agreement with the response and recovery curves measured in the experiment. From the two relations we can obtain that the response and recovery times are 32s and 13 min respectively; the adsorption and the desorption probabilities are 3.12 × 10 -2 s -1 and 1.28 × 10 -3 s -1 respectively. The gas-sensitive sensor consisting of the tapCuPc LB film can detect NH 3 gas down to 2 ppm in air.