Shear Horizontal Surface Acoustic Wave Sensors Based on Polyaniline for Ammonia Gas Sensing

A shear horizontal surface acoustic wave (SH-SAW) sensor coated with polyaniline (PANI) was investigated in this study. The frequency shift of SH-SAW was measured for the response to ammonia in this study. The temperature effect was also discussed in order to find the suitable temperature of operation. The response of the SH-SAW sensor immediately responded the concentration of ammonia gas. Moreover, this sensor presented a sensitivity of 0.03 ppm/ppm at 23°C. The reaponses to ammonia decreased with decreasing temperature below 23°C.