Ammonia gas sensor based on the frequency-dependent impedancecharacteristics of ultrathin polyaniline films.

This paper describes a variety of experiments that reveal the potential application of impedance spec-troscopy (IS) measurements to enhance performance of ultrathin polyaniline (PANI)-based films onflexible substrate to control ammonia gas exposure in the 0?20 ppm range. Further, the device is mechan-ically robust for making electrical contact without lithography. We have employed the IS technique toproper adjust the optimal operation frequency of an easy-to-process, inexpensive and user-friendly PANI-based resistometric detectors in which drift current and delay problems related to electrode effects anddielectric absorption of PANI are insignificant. These requirements place emphasis upon the material anddevice configuration, and the range of frequencies from 10 to 100 Hz corresponds to the ideal workingregion to operate the device to unify sensibility inside 5%, reproducibility, linearity, stability and lowresponse time (