Investigation of the room temperature gas sensing properties of metal–organic charge transfer complex CuTCNQF4

Abstract

The ability to detect and monitor toxic and greenhouse gases is highly important, however to achieve this at room temperature and allow for remote sensing applications is a significant challenge. Here, we tackle this issue and investigate conductometric gas sensors that operate at room temperature using a microstructured CuTCNQF₄ (TCNQF₄ = 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane) sensing layer formed via simply immersing an e-beam evaporated Cu film in an acetonitrile solution of TCNQF₄. These films were characterised by scanning electron microscopy, Fourier transform infra-red, Raman and X-ray photoelectron spectroscopy. The sensors show a significant response to NO₂ and NH₃ gases and a negligible response to ethanol at 25 °C. Significantly a low detection limit of 100 ppb is achieved for NO₂ gas.