Nitrogen oxide gas sensor based on tetra-tertbutyl copper phthalocyanine Langmuir-Blodgett films†

Abstract
A novel allempt lo improve the parameters of a NOx sensor, based on conductivity modulation, is presented. By using tetra-tertbutyl copper phthalocyanine (tlb CuPc) Langmuir-Blodgett (LB) films characterized by high conductivity (10−6Sm cm−1) and thermostability (up to 160°C) the detection of low NOx levels (0.l-103ppm) in air is demonstrated. The response time and the sensitivity are -∼ 1 min and 6nA per decade of NOx concentration respectively. The selectivity of such a sensor could be explained by the difference of the conductivity activation energies for NOx (0.63 eV) and oxygen (0.79 eV).