Bending stress induced improved chemiresistive gas sensing characteristics of flexible cobalt-phthalocyanine thin films

We report chemiresistive gas sensing characteristics of cobalt phthalocyanine films deposited on flexible bi-axially oriented polyethylene terephthalate substrates. Charge carrier mobility in these films systematically decreases upon bending, which implies that bending reduces pi-pi interactions among molecules. At room temperature, these films exhibited a reversible change in resistance on exposure to ammonia (5-50 ppm) along with high sensitivity and selectivity as well as fast response and recovery. The chemiresistive sensing properties were found to improve significantly under bend conditions owing to creation of more numbers of interaction sites. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4800446]