Enhancing p-type Co3O4 Gas Sensing Performances by Fluorine Doping

In the present work, Co3O4-based materials were grown by Plasma Enhanced-Chemical Vapor Deposition (PE-CVD) and tested in the detection of reducing analytes (ethanol, acetone). In particular, Co3O4 and F doped Co3O4 deposits were synthesized in the range 200-400°C on polycrystalline Al2O3 substrates from Ar-O2 plasmas using Co(dpm)2 (dpm = 2,2,6,6-tetramethyl-3,5-heptanedionate) and Co(hfa)2·TMEDA (hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; TMEDA = N,N,N',N'- tetramethylethylenediamine), respectively. In the latter case, a homogeneous fluorine doping throughout the whole deposit thickness was achieved, and its content could be controlled as a function of the deposition temperature. Notably, the sensing performances appreciably improved upon fluorine incorporation into cobalt oxide. To the best of our knowledge, this work is the first example of F doping in p-type metal oxide nanosystems aimed at enhancing their sensing properties.