Abstract: Aimed at the problem of quickly detecting phosphorus-containing toxic gas,we used home-made hybrid PdPc-PANI as the material for sensitive film and designed a binary channel SAW sensor.We expound the basic principle of the sensor and deduce that when using organic film as the intermediate medium of channel,different frequency output Δf was superimposed by a mathematical model using the two mechanisms of physical chemistry adsorption.According to the conditions of sound wave oscillation,we designed a signal gathering circuit whose oscillation frequency is 146±5MHz.Using lithium tantalate as piezoelectric substrate,through MEMS micro-fabrication we made finger-cross electrodes couple and hot film.We adopted vacuum deposition technology to make material of sensitive film into film,which modified the center of the SAW channel to compose the SAW sensor.The testing result indicates that when material has the best sensitivity,the mixture ratio is PdPc0.35PANIO.65.When the chip is heated to 60~80℃,it can increase the performance,the responsive time is less than or equal to 30s;The gas concentration of output and testing is consistent with that in the mathematic model,and is the N-style linear relation of linear change rate -110kHz (mg/m3).The SAW sensor counteracts the interference of gasoline oil and carbon dioxide and so on;Through the checking of stability for 80 days,Δf is less than or equal to ±0.1kHz,which meets the requirement for practical use.

Key words: PdPc-PANI hybrid, SAW sensor, phosphorus-containing toxic gas