Room temperature ppb level Cl2 sensing using sulphonated copper phthalocyanine films

We present room temperature chemiresistive gas sensing characteristics of drop casted sulphonated copper phthalocyanine (CuTsPc) films. It has been demonstrated that these films are highly selective to Cl2 and the sensitivity in the 5–2000 ppb range varies linearly between 65 and 625%. However, for concentrations ≥2000 ppb, the response becomes irreversible, which is found to be due to the chemical bond formation between Cl2 and SO3Na group of CuTsPc films. The X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) data confirms the oxidation of SO3Na group by Cl2 gas.