Hybrid Organotin and Tin Oxide-based Thin Films Processed from Alkynylorganotins: Synthesis, Characterization, and Gas Sensing Properties

Hydrolysis-condensation of bis(triprop-1-ynylstannyl)butylene led to nanostructured bridged polystannoxane films yielding tin dioxide thin layers upon UV-treatment or annealing in air. According to Fourier transform infrared (FTIR) spectroscopy, contact angle measurements, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscopy (SEM) data, the films were composed of a network of aggregated pseudo-particles, as calcination at 600 degrees C is required to form cassiterite nanocrystalline SnO2 particles. In the presence of reductive gases such as H-2 and CO, these films gave rise to highly sensitive, reversible, and reproducible responses. The best selectivity toward H-2 was reached at 150 degrees C with the hybrid thin films that do not show any response to CO at 20-200 degrees C. On the other hand, the SnO2 films prepared at 600 degrees C are more sensitive to H-2 than to CO with best operating temperature in the 300-350 degrees C range. This organometallic approach provides an entirely new class of gas-sensing materials based on a class II organic-inorganic hybrid layer, along with a new way to include organic functionality in gas sensing metal oxides.