Chemi-resistive gas sensing properties of cobalt-phthalocyanine / iron-phthalocyanine composite films

Thin film of cobalt phthalocyanine (CoPc), iron phthalocyanine (FePc) and CoPc-FePc composite were grown on sapphire substrate by molecular beam epitaxy under identical experimental conditions. Composite films showed very high mobility ∼ 110 cm
²
V
⁻¹
s
⁻¹
at room temperature, which is nearly two orders of magnitude higher as compared to the pure CoPc and FePc films. We demonstrate that due to high mobility of composite phthalocyanine films, it showed enhanced sensitivity for chlorine (Cl
2
) gas as compared to pure CoPc and FePc films